Medical applications of Nanomaterials 1774694018, 9781774694015

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Medical Applications of Nanomaterials

MEDICAL APPLICATIONS OF NANOMATERIALS

Edited by: Esha Rami

ARCLER

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www.arclerpress.com

Medical Applications of Nanomaterials Esha Rami

Arcler Press 224 Shoreacres Road Burlington, ON L7L 2H2 Canada www.arclerpress.com Email: [email protected]

e-book Edition 2023 ISBN: 978-1-77469-642-2 (e-book)

This book contains information obtained from highly regarded resources. Reprinted material sources are indicated and copyright remains with the original owners. Copyright for images and other graphics remains with the original owners as indicated. A Wide variety of references are listed. Reasonable efforts have been made to publish reliable data. Authors or Editors or Publishers are not responsible for the accuracy of the information in the published chapters or consequences of their use. The publisher assumes no responsibility for any damage or grievance to the persons or property arising out of the use of any materials, instructions, methods or thoughts in the book. The authors or editors and the publisher have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission has not been obtained. If any copyright holder has not been acknowledged, please write to us so we may rectify.

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© 2023 Arcler Press ISBN: 978-1-77469-401-5 (Hardcover)

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ABOUT THE EDITOR

Dr. Esha Rami is presently working as an Assistant Professor, in the Department of Life science, Parul Institute of Applied Science, Parul University, India. She Did her Post graduated from Ganpat University, Ph.D. in biotechnology from Hemchandracharya North Gujarat University, in the year 2015. She has authored a number of national and international publications in reputed journals.

TABLE OF CONTENTS



List of Figures.................................................................................................xi



List of Tables..................................................................................................xv



List of Abbreviations.................................................................................... xvii

Preface................................................................................................... ....xxiii Chapter 1

Introduction to Nanotechnology and its Medical Applications.................. 1 1.1. Introduction......................................................................................... 2 1.2. History of Nanotechnology.................................................................. 2 1.3. Classification of the Nanomaterials...................................................... 7 1.4. Manufacturing Methods....................................................................... 8 1.5. Applications of Nanotechnology.......................................................... 9 1.6. Medical Utilization of Nanomaterials................................................ 12 1.7. Applications...................................................................................... 16 1.8. Applications in Ophthalmology......................................................... 22 1.9. Applications of Nanotechnology in Altered Medicated Textiles.......... 26 References................................................................................................ 27

Chapter 2

Functionalization and Biocompatibility of Nanomaterials....................... 35 2.1. Introduction....................................................................................... 36 2.2. Conversion of Nanomaterial Into Water-Soluble Form....................... 37 2.3. NM Bioconjugation........................................................................... 51 2.4. Applications of Biocompatible Nanomaterials................................... 60 References................................................................................................ 69

Chapter 3

Targeted Drug Delivery............................................................................ 79 3.1. Introduction....................................................................................... 80 3.2. Nanomaterials as Vehicles for Drug Delivery..................................... 80 3.3. Factors to Consider for NPS That Will Be Used for Drug Delivery...... 84 3.4. Drug Loading..................................................................................... 87

3.5. NM Targeting for Drug Delivery......................................................... 95 3.6. Binding and Uptake......................................................................... 102 3.7. Drug Release and Biodegradation.................................................... 105 3.8. Factors Affecting Drug Release......................................................... 106 3.9. Various NMS for Drug Delivery........................................................ 107 References.............................................................................................. 109 Chapter 4

Fundamentals of Nanobiosensors........................................................... 121 4.1. Introduction..................................................................................... 122 4.2. Nanobiosensors Unique Characteristics........................................... 124 4.3. Immobilization Strategies................................................................. 126 4.4. Self-Assembled Monolayers (SAMS)................................................. 132 4.5. Applications of Nanobiosensors....................................................... 136 References.............................................................................................. 144

Chapter 5

Application of Nanomaterials in Nanopharmacology............................ 151 5.1. Introduction..................................................................................... 152 5.2. Current Issues and Status of Nanopharmacology.............................. 152 5.3. NMS for Gene Delivery................................................................... 155 5.4. Nanoimmunotherapy....................................................................... 158 5.5. NMS as Contrast Agents................................................................... 163 5.6. Magnetic Ion P-Mediated Circulating Tumor Cell Isolation............... 164 5.7. Design Trends for Personalized Medicine......................................... 166 References.............................................................................................. 172

Chapter 6

Applications of Nanomaterials in Nanomedical Devices........................ 179 6.1. Introduction..................................................................................... 180 6.2. Nanorobots...................................................................................... 180 6.3. Prosthesis......................................................................................... 182 6.4. Tissue Engineering (TE)..................................................................... 185 6.5. Cell Repair....................................................................................... 190 References.............................................................................................. 192

Chapter 7

Nanotechnology in Tissue Engineering................................................... 197 7.1. Introduction..................................................................................... 198 7.2. 3D In-Vitro Systems......................................................................... 199

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7.3. Cellular Microenvironment.............................................................. 205 7.4. 3D Technology and Tissue Engineering (TE)...................................... 207 References.............................................................................................. 209 Chapter 8

Nanoparticles in Gene Therapy.............................................................. 215 8.1. Introduction..................................................................................... 216 8.2. Gene Therapy and the Methods of Gene Delivery............................ 217 8.3. Types of Nanoparticles..................................................................... 220 8.4. Gene Therapy Applications.............................................................. 224 References.............................................................................................. 228

Index...................................................................................................... 233

ix

LIST OF FIGURES

Figure 1.1. Nanoscale and nanostructures Figure 1.2. Graphic representation of several kinds of pharmaceutical nanosystems Figure 1.3. Surface functionalized gold (Au) nanoparticles Figure 1.4. Structure of the liposomes Figure 1.5. Schematic diagram of the dendrimers displaying core, surface, and branches Figure 1.6. Nanotechnology applications in medicine and stem cell biology Figure 1.7. Delivery of the nanomedicine to the central nervous system via BBB Figure 1.8. Nanomaterials (NMs) as contrast agents for the diagnosis of AD (Alzheimer’s disease) Figure 1.9. Schematics of different nanotechnology-based drug delivery systems Figure 1.10. Application of nanotechnology in tissue engineering Figure 1.11. Examples of different nanopharmaceuticals Figure 2.1. Diagram of transforming hydrophobic nanomaterials to hydrophilic nanomaterials loaded with the drug Figure 2.2. Ligand exchange of the CuInS2 NPs (nanoparticles) Figure 2.3. Diagram of hydrophilic carboxyl-functionalized nanomaterials carrying the drug (left) or the drug and Ab (right) Figure 2.4. Transmission electron microscopy of PEG-encapsulated 30-nanometers diameter IOMNPs Figure 2.5. DLS and TEM of carboxyl-utilized PEGylated IOMNPs Figure 2.6. Digital image of SK-BR3 breast cancer cells exposed to the QD-antiEpCAM. The quantum dots had a diameter of ~8 nanometers emitting at 620 nanometers Figure 2.7. Image of SK-BR3 breast cancer cells stained with green color emitting quantum dots emitting at 530 nanometers fixed to Ab against the cell membrane proteins. The quantum dots-Ab are observed as dots along the membrane of the cell to bring visible color to the cells Figure 2.8. Applications of biocompatible NMs Figure 2.9. Applications of carbon nanomaterials in manufacturing of biosensors Figure 2.10. Applications of nanomaterials in detection and treatment of cancer Figure 2.11. Mesoporous silica nanoparticle composite material for drug delivery

Figure 2.12. Gas sensors synthesized from carbon nanotubes Figure 2.13. Schematic illustrations for the silicon nanowire field-effect transistor (SiNW-FET) chip (A); microfluidic channels during antibody modifications (dualchannel); (B) and biosensing measurements (single channel) (C) Figure 3.1. Schematic illustration of an NM with (A) encapsulated; or (B) surfacebound drugs. The NM drug carrier is altered with a targeting molecule Figure 3.2. DLS data for water-soluble 30-nm IOMNPs that are encapsulated using amphiphilic polymers that possess carboxyl groups causes them water-soluble Figure 3.3. TEM demonstration of organic soluble 20-nm IOMNP using narrow size distribution Figure 3.4. SHP 10 loaded with dox which was released at pH 2–5 Figure 3.5. Schematic illustration of an NM for (A) drug delivery; and (B) targeted drug delivery Figure 3.6. Agarose gel electrophoresis of (A) QD without (left) and with antibody (right); and (B) IOMNP without (right) and with antibody (left) covalent conjugated antibody Figure 3.7. Macrophage uptake of QD-vaccine candidates. Macrophages were marked with CD11 and had a green dye. The vaccine candidate was covalently conjugated by a red-emitting QD that was around 12 nm in diameter Figure 4.1. QD-based nanobiosensors that is an (A) antigen; and (B) antibody for analyte’s schematic figures Figure 4.2. QD-based nanobiosensor for an entire cell such as breast cancer cell SKBR3’s schematic drawing Figure 4.3. Schematic illustration of AuNP with ssDNA bound through charge-charge interaction utilizing DNA’s negative phosphate backbone Figure 4.4. Agarose gel electrophoresis of QD in the presence and absence of conjugated BSA Figure 4.5. Agarose gel electrophoresis of IOMNP in either the presence or absence of conjugated BSA Figure 4.6. Introduction of SK-BR3 cells to QD-anti-HER2 following their capture on an antibody-modified silanized glass slide Figure 4.7. Employment of HRP enzyme label for determination in IOMNP-based capture of proteins from SK-BR3 breast cancer cells in an ELISA. Signal following the elimination of IOMNP ELISA (A) in the absence of stop solution; and (B) in the presence of stop solution Figure 5.1. Schematic of targeted drug delivery by applying engineered nanomaterials Figure 5.2. Amine functionalized IOMNP were applied to capture dsDNA that was since lysed SK-BR3 cells after capture and acridine orange (AO) addition, 3-SUP2 after

xii

capture+AO, 4-SUP3 after capture+AO, 5-SUP4 after capture+AO, 6-AO +buffer, 7-buffer) Figure 5.3. Antibody retort in Swiss Webster mice. Antibody titers from: (A) mice vaccinated (IP) through rMSP1-QD; (B) mice vaccinated with diverse adjuvant platforms; (C) in mice vaccinated with rMSP1-QD Tertiary bleed antibody response through different routes (i.p., i.m., and s.c.). Horizontal bars specify mean antibody titers. Substantial variances in ELISA titers among vaccination groups are designated with p-values Figure 5.4. IFN-γ. and IL-4 responses persuaded by rMSP1-QD and further adjuvants. (A) MSP1 specific IL-4; and (B) IFN-γ as determined through ELISPOT. Horizontal bars indicate mean SFU. 21 days after the last immunization, mouse splenocytes were collected Figure 5.5. Characterization of IO nanoparticles. (A) Transmission electron microscopy image of the hydrophobic inorganic core of the IO nanoparticles, presentation a diameter around 27 ± 5 nm; (B) transmission electron microscopy image of antibody conjugated biocompatible water-soluble IO, IO-Ab, applying phosphotungstic acid for background staining; (C) light scattering characteristics of biocompatible water-soluble IO showing a hydrodynamic size about 33 nm through a zeta potential of –51 mV, and IO-Ab show a hydrodynamic size around 41 nm and zeta potential of –36 mV; (D) agarose gel electrophoresis of biocompatible water-soluble IO-Ab (on right), and IO (on left) the electric pole is +ve for the bottom and-ve for the top Figure 5.6. Stages of administering personalized medicine Figure 5.7. Schematic illustration of synthesis procedure for contrast agents Figure 5.8. Multifunctional materials for therapeutic studies Figure 6.1. Femtolaser nanosurgery of key and peripheral SFs. Ignorable modifications in cell area take place after femtolaser disruption of a single central fiber (top); dramatic changes in cell area after ablation of a single peripheral fiber (bottom). Right: highmagnification zooms of the boxed zones that more clearly exhibit the severed SF. Left: low-magnification snapshots displaying the outline of the whole cell. All illustrations are overlays of mCherry-LifeAct fluorescence before ablation (red) plus 30-min postablation (green). Scale bar for right and left panels = 20 and 10 µm, respectively Figure 6.2. Comparative sizes of nanomaterials with cells, proteins, tissues, etc Figure 6.3. Applications of nanomedical devices in different diseases Figure 6.4. In tissue engineering, applications of carbon-based nanomaterials Figure 6.5. Nanomaterials in bone repair Figure 7.1. A multidisciplinary approach of 3-D in vitro technology Figure 7.2. Complete fabrication of 3D scaffolding materials using freeze-drying techniques Figure 7.3. The key and basic components of an extracellular matrix shown in this cellular microenvironment (ECM) xiii

Figure 7.4. Tissue engineering technology is depicted in this diagram Figure 8.1. Diagram of gene therapy mechanism Figure 8.2. Physical approaches of gene delivery Figure 8.3. Nanoparticles for cancer gene therapy Figure 8.4. Gene therapy applications

xiv

LIST OF TABLES Table 1.1. Periodical advancement in nanotechnology Table 8.1. Structure, properties, and successful attempts of diverse nanoparticles

LIST OF ABBREVIATIONS

µCP

Microcontact Printing

3D

Three-Dimensional

Abs

Antibodies

AD

Alzheimer’s Disease

ADME

Distribution, Absorption, Excretion, and Metabolism

AgNP

Silver Nanoparticles

APTS

Aminopropyltriethoxysilane

ASGP-R

Asialoglycoprotein Receptor

ATR-FTIR

Attenuated Total Reflectance FTIR

Au

Gold

AuNMs

Gold Nanomaterials

AuNPs

Gold Nanoparticles

BBB

Blood-Brain Barrier

cDNA

Complementary Deoxyribonucleic Acid

CNS

Central Nervous System

CNT

Carbon Nanotube

CS

Chitosan

CTCs

Circulating Tumor Cells

CV

Cyclic Voltammetry

CVD

Chemical Vapor Deposition

DDSs

Drug Delivery Systems

DHLA-PEG

PEG-Terminated Dihydrolipoic Acid

DLS

Dynamic Light Scattering

DMF

Dimethylformamide

DNA

Deoxyribonucleic Acid

DOTAP

Dioleoyl-Sn-Glycerol-3-Trimethylammonium-Propane

dox

Doxorubicin

DPA

Dendrigraft Poly-L-Lysine Polyethyleneglycol-Angiopep

DPBS

Dulbecco Phosphate-Buffered Saline

dsDNA

Double-Stranded DNA

EBL

Electron Beam Lithography

ECM

Extracellular Matrix

EDC

Ethyl-Aminopropyl-Carbodiimide Hydrochloride

EGFP

Enhanced Green Fluorescent Protein

EGFR

Anti-Epidermal Growth Factor Receptor

ELISA

Enzyme-Linked Immunosorbent Assay

EpCAM

Epithelial Cell Adhesion Molecules

EPR

Permeation and Retention

Fe

Iron

FET

Field Effect Transistor

FLUAV

Influenza A virus

FRET

Fluorescence Energy Transfer

FTIR

Fourier-Transform Infrared

GALT

Gut-Associated Lymphoid Tissue

GNOME

Gold Nanoparticle-Mediated

HA

Hemagglutinin A

HA

Hyaluronic Acid

HERs

Human Epithelial Receptors

HI

Hydrophobic Interaction

HUVEC

Human Macrophages, the Umbilical Vein Endothelial Cells

ICP-AES

Inductively Coupled Plasma Atomic Emission Spectroscopy

IFN-γ

Interferon-γ

IgE

Immunoglobulin E

IL Interleukin IOMNP

Iron Oxide Magnetic Nanoparticle

IONPs

Iron Oxide Nanoparticles

IS

Immune System

ISCOMs

Immune-Stimulating Complexes

LSPR

Localized Surface Plasmon Resonance

MCT

Medium-Chain Triglycerides

MDR

Multidrug Resistance

MHC

Major Histocompatibility Complex

mPEG-OH

Polyethylene Glycol Monomethyl Ether

MPL

Monophosphoryl Lipid xviii

MPS

Mercaptopropyltris(Methyloxy)Silane

MPS

Mononuclear Phagocyte System

MRI

Magnetic Resonance Imaging

MW

Molecular Weight

MWCNT

Multiwalled Carbon Nanotube

MWCO

Molecular-Weight Cutoff

NDEO

Nano-Scale Dispersed Eye Ointment

NESD

Nano-Enabled Scaffold Device

NHS

N-Hydroxy Succinamide

NIL

Nanoimprint Lithography

NIR

Near-Infrared

NM

Nanomaterial

NMR

Nuclear Magnetic Resonance

NPs

Nanoparticles

NS

Nanostructures

NSL

Nanosphere Lithography

OA

Oleic Acid

OAD

Oblique Angle Deposition

OAP

Oblique Angle Polymerization

OD

Optical Density

ODA

Octadecylamine

ONTs

Oligonucleotides

PAP

Papaverine-Free Base

PBS

Phosphate-Buffered Saline

PD

Parkinson’s Disease

PDAC

Pancreatic Ductal Adenocarcinoma Cells

pDNA

Plasmid DNA

PEG

Polyethylene Glycol

PEI

Polyethyleneimine

PET

Positron Emission Tomography

pI

Isoelectric Point

PL

Photoluminescence

PLE

Photoluminescence Excitation

POC

Point-of-Care xix

PVA

Polyvinyl Alcohol

QDs

Quantum Dots

QY

Quantum Yield

RES

Reticuloendothelial System

RGD

Tripeptide Arginine-Glycine-Aspartate

RSV

Respiratory Syncytial Virus

SAMs

Self-Assembled Monolayers

SBB

Sodium Borate Buffer

SEM

Scanning Electron Microscopy

SERS

Surface-Enhanced Raman Scattering

SFF

Solid Free Form

siRNA

Small Interfering RNA

SLNs

Solid Lipid Nanoparticles

SPECT

Single-Photon Emission Computed Tomography

SPIO

Superparamagnetic Iron Oxide

SPION

Superparamagnetic Iron Oxide Nanoparticles

SPR

Surface Plasmon Resonance

ssDNA

Single-Stranded DNA

SSLs

Sterically Stabilized Liposomes

STM

Scanning Tunneling Microscopy

TB

Tuberculosis

TCR

T-Cell Receptor

TE

Tissue Engineering

TEG

Tetraethylene Glycol

TEM

Transmission Electron Microscopy

TEOS

Tetraethylorthosilicate

THF

Tetrahydrofuran

TJ

Tight Junction

TMAH

Tetramethylammonium Hydroxide

TNTs

Titanate Nanotubes

TOP

Trioctylphosphine

TOPO

Trioctylphosphine Oxide

UV

Ultraviolet

VACNF

Vertically Aligned Carbon Nanofiber xx

VEGF

Vascular Endothelial Growth Factor

VIP

Vasoactive Intestinal Peptide

XPS

X-Ray Photoelectron Spectroscopy

XRD

X-ray Diffraction

ZnO

Zinc Oxide

xxi

PREFACE

Nanotechnology is the cutting-edge and innovative technology of the current era. Nanotechnology helps scientists and researchers to discover, illustrate, and exploit the unique characteristic of matter at extran emely small scale, i.e., nanoscale. Presently, nanomaterials are being developed to address the problems of almost every sector of life, including energy, environment, medicine, information technology, and space sciences. Several potential uses of nanotechnology and nanomaterials have been publicized in the scientific press for the capability of nanoscience to revolutionize the earth into a fictional place that only existed as a dream in the books. Outside of massive hype and assumptions, contemporary applications of nanodevices and nanomaterials (that are already influencing global commerce) are living evidence of nano-revolution. This textbook is intended to encompass topics regarding the development, growth, and characterization of nanomaterials. The detailed analysis of electrical, chemical, optical, and physical characteristics of nanomaterials and derived nanodevices (with emphasis on medical applications) is also offered in the book. It is aimed at providing an overview of various properties and applications of nanomaterials to graduate students in the field of materials science, electrical engineering, applied physics, and chemical engineering. The book also contains the fundamental properties of micro and nanosystems to utilize the advantageous side of nanomaterials in the medical sector. Based on the published data available in the field of nanotechnology, this book demonstrates the procedures for the synthesis of nanomaterials and their use in various medical applications. The book also discusses the characterization techniques for unveiling the thermal, optical, electronic, and magnetic properties of nanomaterials. This book consists of eight chapters. Each chapter of the book offers a detailed explanation of a particular topic. Chapter 1 introduces the readers to the fundamentals of nanotechnology with a brief overview of its medical applications. Classification of nanomaterials and their synthesis routes are also discussed in the chapter. Chapter 2 focuses on the illustration of the functionalization and biocompatibility of nanomaterials. Drug delivery is a hot topic during this era of technological developments. Chapter 3 discusses different aspects of drug delivery using nanomaterials and their derivatives. Chapter 4 illustrates the fundamental concepts of biosensors and nanobiosensors synthesized from novel nanomaterials. Different applications of nanobiosensors are also discussed in the chapter. Chapter 5 presents a detailed overview of the pharmaceutical aspects of nanomaterials and nanotechnology.

Chapter 6 contains information about different nanomedical devices which are employed in prosthesis, tissue engineering (TE) and cell repair. Chapter 7 offers a detailed discussion about the applications of nanomaterials in TE. Finally, Chapter 8 focuses on the applications of nanomaterials and nanotechnology in gene therapy. This book can serve as a guide for getting knowledge about numerous aspects of nanotechnology and nanoscience in order to materialize modern medicines and devices from nanomaterials. This book is equally beneficial for students, professors, researchers, and professionals working in the field of medicine and biotechnology. Moreover, people from multidisciplinary fields can also benefit from the book.

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CHAPTER

1

INTRODUCTION TO NANOTECHNOLOGY AND ITS MEDICAL APPLICATIONS

CONTENTS 1.1. Introduction......................................................................................... 2 1.2. History of Nanotechnology.................................................................. 2 1.3. Classification of the Nanomaterials...................................................... 7 1.4. Manufacturing Methods....................................................................... 8 1.5. Applications of Nanotechnology.......................................................... 9 1.6. Medical Utilization of Nanomaterials................................................ 12 1.7. Applications...................................................................................... 16 1.8. Applications in Ophthalmology......................................................... 22 1.9. Applications of Nanotechnology in Altered Medicated Textiles.......... 26 References................................................................................................ 27

2

Medical Applications of Nanomaterials

1.1. INTRODUCTION Development in the area of nanotechnology and its uses in the area of pharmaceuticals and medicines has transformed the 20th century. Nanotechnology deals with the study of very small structures (Yousaf and Salamat, 2011). The prefix nano is a Greek word meaning dwarf. The word nano means miniature or very small size. Nanotechnology is the handling of individual molecules, compounds, or atoms in structures to yield devices and materials with exceptional properties. Nanotechnology includes work from the top-down, i.e., decreasing the size of very large structures into the smallest structure for instance. photonics uses in nanoengineering and nanoelectronics, bottom-up or top-down, which includes varying individual molecules and atoms into nanostructures and more carefully bear a resemblance to chemistry biology (Silva, 2004; Deb et al., 2012). Nanotechnology usually deals with materials having the size of 0.1– 100 nanometers; though it is also essential that these materials must exhibit different properties like electrical conductance chemical reactivity, optical effects, physical strength, and magnetism, from heavy materials as an outcome of the small size (Wang et al., 2009). Nanotechnology functions on the matter having dimensions in the range of nanometer-scale length, and therefore can be utilized for a wide range of uses and the formation of several kinds of nanodevices and nanomaterials (Soni, 2016; Nasrollahzadeh et al., 2019).

1.2. HISTORY OF NANOTECHNOLOGY The advancement in the area of nanotechnology began in 1958, and the several phases of development have been given in Table 1.1. Nanoscale is a place where the properties of the common things are concluded above the scale of the atom. The objects of the nanoscale have as a minimum one dimension (length, depth, height) that measures between 1 and 999 nanometers (Figure 1.1). A brief clarification of the pharmaceutical nanosystem is given as follows: As displayed in the schematic diagram (Figure 1.2), pharmaceutical nanotechnology is generally divided into two basic kinds of nanotools viz. nanodevices and nanomaterials. The materials can further be categorized into nano-structured and nanocrystalline materials (Romig et al., 2007; Subedi, 2014). Nanostructure comprises nanoparticles, micelles, dendrimers, metallic nanoparticles, drug conjugates, etc.

Introduction to Nanotechnology and Its Medical Applications

3

Figure 1.1: Nanoscale and nanostructures. Source: https://www.researchgate.net/figure/Nanoscale-integration-ofnanoparticles-and-biomolecules_fig2_320132877.

• •

Carbon Nanotubes (CNTs): These are tiny macromolecules that are of unique significance for biomedical utilization (Figure 1.3). Liposomes: These have been broadly explored, and most of the progressed nanocarriers for new and targeted drug delivery because of the small size, liposomes are 50 to 200 nanometers in size. When dry phospholipids are normally hydrated, sealed vesicles are created (Figure 1.4).

Figure 1.2: Graphic representation of several kinds of pharmaceutical nanosystems.

Source: https://www.researchgate.net/publication/274837597_Nanotechnology_and_its_Applications_in_Medicine.

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Medical Applications of Nanomaterials

Table 1.1: Periodical Advancement in Nanotechnology Year

Advancement in Nanotechnology

1959

R. Feynman started the thought process

1974

The word nanotechnology for the 1st time was applied by Taniguchi.

1981

IBM Scanning Tunneling Microscope

1985

Bucky Ball

1986

First-ever book on nanotechnology “Engines of Creation” published by K. Eric Drexler

1989

The logo of IBM was made with the individual atoms

1991

S. Iijima discovered CNT (carbon nanotube) for the 1st time.

1999 2000

The first nanomedicine book “Nanomedicine” was published by R. Freitas For the 1st time, National Nanotechnology Initiative was initiated

2001

For an emerging theory of nm-scale electronic device and characterization and synthesis of nanowires and carbon nanotubes, the Feynman Prize in the field of Nanotechnology was given

2002

Feynman Prize in the field of Nanotechnology was given for utilizing DNA to empower the self-assembly of novel structures and for progressing the ability to model the molecular machine systems.

2003

Feynman Prize in the field of Nanotechnology was given for modeling the electronic and molecular structures of novel materials and for incorporating particular molecule biological motors with the nanoscale silicon devices.

Introduction to Nanotechnology and Its Medical Applications

2004

5

1st policy conference on advanced nanotech was conducted. The first center for the nanomechanical systems was developed, Feynman Prize in the field of Nanotechnology was given for scheming stable protein structures and for making the new enzyme with a modified function.

2005–2010

Three-dimensional Nano systems such as robotics, threedimensional networking, and the active nano products that alter their state during utilization were prepared.

2011

Period of the molecular nanotechnology began.

Liposomes are versatile, biocompatible, and have better entrapment efficiency. Liposomes find utilization as long circulatory and inactive and passive delivery of protein, peptide, and gene (Solaiman et al., 2017). •

•

Dendrimers: These are hyperbranched, having structures just like trees. It comprises three different regions: branching units, a closely packed surface, and the core moiety (Figure 1.5). It possesses a globular structure and surrounds internal cavities. The size of the dendrimer is less than 10 nm. These are utilized for a long due to their shape, size, and exclusive physical properties. Nanotubes possess some special benefits over the other drug diagnostic and delivery systems (Figure 1.3) because of their exclusive physical properties (Wang et al., 2010; AbiodunSolanke et al., 2014). Metallic Nanoparticles: They have been utilized in drug delivery, particularly in cancer treatment, and also used in biosensors. Amongst several metals, gold, and silver nanoparticles (AgNP) are the main scale building blocks having control over composition, size, etc. The manufacturing of materials will be developed by further accumulating into the larger structures with intended properties. Without machining, polymers, metals, and ceramics can be made in precise shapes. Nanotechnology can help chemical catalysis because of the very large ratio of surface to volume. Several applications of the nanoparticles in the range of catalysis from the fuel cell to the photocatalytic devices and catalytic converters. It is also vital for chemical production. A recent revolution in catalysis is because of the availability of limitless commercial quantities of zeolites (Lavan et al., 2003; Kubik et al., 2005).

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Medical Applications of Nanomaterials

Figure 1.3: Surface functionalized gold (Au) nanoparticles. Source: https://www.researchgate.net/figure/Surface-functionalized-gold-nano-particles_fig1_274837597.

Figure 1.4: Structure of the liposomes. Source: https://www.slideshare.net/bharathpharmacist/liposomes-39686019.

Introduction to Nanotechnology and Its Medical Applications

7

Figure 1.5: Schematic diagram of the dendrimers displaying core, surface, and branches. Source: https://www.omicsonline.org/articles-images/2161-0444-5-081-g005. html.

1.3. CLASSIFICATION OF THE NANOMATERIALS Nanomaterials can generally be categorized dimension wise into the following categories (Boisseau and Loubaton, 2011; Accomasso et al., 2012). •

Classification Instances: – Tubes, platelets, fibers have dimensions < 100 nanometers. – Nanowires, nanorods have dimensions < 100 nanometers. – Particles, hollow spheres, quantum dots (QDs) have 3 or 0 Dimensions < 100 nanometers. On the phase composition basis, nanomaterials in dissimilar phases can be categorized as: • • •

The nanomaterial is known as the single-phase solids. Crystalline, amorphous layers, and particles are incorporated in this class. Coated particles, matrix composites are incorporated in the multiphase solids. Multi-phase systems of the nanomaterial comprise aerogels, colloids, Ferrofluids, etc.

8

Medical Applications of Nanomaterials

1.4. MANUFACTURING METHODS The two main methods to obtain nanomaterials are as follows: the bottomup method and the top-down method (Glezer, 2011; Deb et al., 2012). The bottom-up approach yields components which are composed of single molecules, and the covalent forces hold these components together that are quite stronger as compared to forces that hold together the macro-scale components. A vast amount of information might be stored in the devices made from the approach of bottom-up. For instance, utilization of the AFM, liquid phase methods based on the inverse micelles, CVD (chemical vapor deposition), sol-gel processing, laser pyrolysis, and the molecular selfassembly utilize bottom-up method for the nanoscale manufacturing of the material (Hulla et al., 2015; Cavalcanti et al., 2007). Top manufacturing includes the making of parts through techniques like carving, molding, and cutting, and because of the limitations in the procedures highly innovative nanodevices are to be manufactured. Milling, laser ablation, nano-lithography, physical vapor deposition, hydrothermal technique, and electrochemical method utilizes a top-down method for nanoscale material manufacturing (Toumey, 2008; Ochekpe et al., 2009). Each element of the periodic table can be used in nanotechnology dependent upon the material which is going to be fabricated vary from nanomedicine to nano concrete through nanoelectronics. Nanotechnology allows synthesizing the nanoscale building blocks having control on composition, size, etc. The manufacturing of materials will be developed by further accumulating into the larger structures with intended properties. Without machining, polymers, metals, and ceramics can be made in precise shapes (Allen and Cullis, 2004; Leon et al., 2020). Nanotechnology can help chemical catalysis because of the very large ratio of surface to volume. Several applications of the nanoparticles in the range of catalysis from the fuel cell to photocatalytic devices and catalytic converters. It is also vital for chemical production. A recent revolution in catalysis is because of the availability of limitless commercial quantities of zeolites (Choi and Mody, 2009; Bertrand and Leroux, 2012).

Introduction to Nanotechnology and Its Medical Applications

9

1.5. APPLICATIONS OF NANOTECHNOLOGY The dissimilar fields that find possible applications of nanotechnology are given as follows (Nagy et al., 2012; Buzea and Pacheco, 2017): • • • • •

Health and medicine; Transportation; Electronics; Space exploration; Energy and environment.

1.5.1. Nanotechnology in Medicine and Health Even today several diseases such as diabetes, Parkinson’s disease (PD), cancer, Alzheimer’s disease (AD), multiple sclerosis, and cardiovascular diseases along with different types of serious infectious or inflammatory diseases constitute a high number of complex and serious illnesses which are posturing a major issue for all of the mankind. The application of nanotechnology working in the area of medicine and health is nanomedicine. Nano-medicine utilizes nanomaterials and nano-electronic biosensors. Nanomedicine will help molecular nanotechnology in the future. The medical field of nanoscience usage has many anticipated benefits and is possibly valuable for the human race (Minchin, 2008; Stone et al., 2010). With the assistance of nanomedicine timely detection and avoidance, enhanced diagnosis, appropriate treatment, and the follow-up of diseases are feasible. Specific nanoscale particles are utilized as labels and tags, biological can be carried out rapidly, and testing has become flexible and sensitive. Gene sequencing has generally become more effective with the discovery of nanodevices such as gold nanoparticles (AuNPs), the gold (Au) particles when tagged with the short sections of DNA can be utilized for recognition of genetic sequence in the sample (Hollmer, 2012; Sudha et al., 2018). With the assistance of nanotechnology, impaired tissue can be repaired or reproduced. These artificially stimulated cells are utilized in tissue engineering (TE), which may modernize the transplantation of artificial implants or organs (Figure 1.6) (Wohlleben, 2012; Ieracitano et al., 2021).

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Figure 1.6: Nanotechnology applications in medicine and stem cell biology. Source: https://www.semanticscholar.org/paper/Nanotechnology-and-itsApplications-in-Medicine-Nikalje/75ba8355d231495087a7f2fd3c83ce2e6 6f83480.

Advanced biosensors with new features can be advanced with the assistance of CNTs (Carbon nanotubes). The biosensors can be utilized for astrobiology and can brief study the origins of life. This technology is being utilized to progress sensors for the diagnostics of cancer. Though CNT is inert, it generally can be put into use at the tip with the probe molecule. The study utilizes AFM as the experimental platform to get information about (Handy et al., 2011; Gebel et al., 2014): •

Probing molecule to assist as a signature of the leukemia cells recognized; • Current flow because of hybridization will be through CNT electrode the IC chip; • Prototype biosensors catheter advancement. Nanotechnology has made an exceptional contribution in the area of stem cell study. For instance, MNPs (magnetic nanoparticles) have been successfully utilized to a group and isolate stem cells. The QDs have been utilized for tracing and molecular imaging of the stem cells, for delivery of drugs or genes into the stem cells, and nanomaterials like CNTs, fluorescent MNPs, and fluorescent CNTs have been utilized. Exclusive nanostructures were made for manageable regulation of proliferation, and separation of the stem cells is accomplished by designing exclusive nanostructures.

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All of these advances accelerate the growth of stem cells for the usage in regenerative medicine (Wang et al., 2009; Boverhof et al., 2015). The current uses of nanotechnology in stem cell research assure to open novel opportunities in regenerative medicine. Therefore, nanotechnology can be a beneficial tool to image and track the stem cells to drive their separation into particular cell lineage and eventually to comprehend their biology. This will lead to stem cell-centered therapeutics for the avoidance, diagnosis, and handling of human diseases (West and Halas, 2000; Soni, 2016). Nanodevices can be utilized in stem cell studies in imaging and tracking them. It has its uses for basic science along with translational medicine. The stem cells can normally be modified by mixing nanocarriers with the biological molecules (Figure 1.6). Nanodevices can usually be utilized for intracellular access and smart delivery and sense of the biomolecules. The technologies have an impact on TE studies and stem cell microenvironment and have the potential for biomedical uses (Accomasso et al., 2012; Smith et al., 2013).

1.5.2. Nanotechnology, Environment, and Energy Nanotechnology will generally play a serious role in the coming 50 years by guarding the environment and giving adequate energy to the growing world. The developed methods of nanotechnology can aid energy storage, energy conversion into other forms, ecofriendly materials manufacturing, and better improved renewable sources of energy (Seil and Webster, 2012; Qu et al., 2013). Nanotechnology can be utilized for the cheap production of energy and restoration energies, in nano-catalysis, fuel cells, solar technology, and hydrogen technology. CNT fuel cells are utilized for hydrogen storage, therefore find application in power cars. Nanotechnology is utilized on photovoltaics in order to make them lightweight, cheap, and more effective, which can decrease the combustion of engine contaminants by the nanoporous filters and can mechanically clean the exhaust, with the aid of catalytic converters composed of the nanoscale noble metal particles and with the help of catalytic coatings on the cylinder walls and also catalytic nanoparticles as a preservative for fuels (Alexander, 2009; McIntyre, 2012). Nanotechnology can aid in developing new green and eco-friendly technologies that can diminish unwanted contamination. Solid-state lighting can decrease the total consumption of electricity. Nanotechnological methods

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can lead to strong energy reduction consumption for lighting (Lanone and Boczkowski, 2006).

1.6. MEDICAL UTILIZATION OF NANOMATERIALS Nanomedicine is a comparatively novel area of science and technology. Through intermingling with biological molecules at the nanoscale, nanotechnology widens the area of research and utilization. Collaborations of nanodevices with the biomolecules can be comprehended in an extracellular medium and within the human cells. Function at nanoscale permits the exploitation of the physical properties dissimilar from those perceived at microscale like the volume to surface ratio (Tonelli et al., 2015). Two forms of nanomedicine that have been tested in rats and are waiting for human trials; utilization of gold (Au) nanoshells to aid diagnose and treat cancer, and the utilization of liposome as vehicles for the transport of drug and as vaccine adjuvants (Wang et al., 2010; Boisseau and Loubaton, 2011). Likewise, detoxification of drugs is another use of nanomedicine which generally has been utilized effectively in rats. The medical technologies making use of smaller devices are normally less invasive and can probably be inserted within the body, and they have much shorter biochemical reaction times. As compared to classic drug delivery nanodevices are more sensitive and faster (Lavan et al., 2003).

1.6.1. Drug Delivery In nanotechnology, nanoparticles are utilized for particular site drug delivery. In this method, the needed drug dose is utilized, and the side effects are significantly lowered as an active agent is accumulated in the morbid portion only. The highly selective method can reduce pain and costs to the patients. Therefore, a variety of the nanoparticles like dendrimers, and nanoporous materials discover the application. Micelles attained from the block copolymers are utilized for drug encapsulation. Micelles carry the molecules of small drugs to their anticipated location. Likewise, nanoelectromechanical systems are used for the active discharge of drugs. Iron (Fe) nanoparticles or Au (gold) shells are finding vital applications in the treatment of cancer. The targeted medicine decreases the consumption of drugs and expenses of treatment, making the treatment cost-effective (Sahoo et al., 2008). Nanomedicines utilized for the delivery of the drug, are composed of nanoscale molecules or particles which can enhance drug bioavailability.

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For increasing bioavailability at particular places in the entire body and over a while, targeting a molecule is done by nanoengineered devices like nanorobots (Cavalcanti et al., 2007). The targeting of molecules and delivery of the drugs are carried out with cell accuracy. Another area is In vivo imaging where Nanodevices and tools are being made for in vivo imaging. Utilizing nanoparticle images like in MRI and ultrasound, nanoparticles are utilized as a contrast. The nanoengineered materials are being made for efficiently treating diseases and illnesses like cancer. With the development of nanotechnology, biocompatible nanodevices can generally be made which will identify the cancerous cells and spontaneously assess the disease, will threat, and prepare reports (Zarbin et al., 2010). The therapeutic and pharmacological drug properties can be enhanced by appropriate designing of the drug delivery systems (DDSs), by utilization of polymer and lipid-centered nanoparticles (Allen and Cullis, 2004). The backbone of this system is the ability to change the biodistribution and pharmacokinetics of the drug. The nanoparticles are made to avert the defense mechanisms of the body can be utilized to enhance drug delivery (Bertrand and Leroux, 2012). A novel, complex mechanism of drug delivery is being made, which can obtain drugs via cell membranes and into the cell cytoplasm, thus increasing effectiveness. One way for the molecules of the drug to be utilized more efficiently is a triggered response. Drugs that are kept in the body can normally activate on receiving a specific signal. The drug having poor solubility will be substituted by the drug delivery system, having enhanced solubility because of the existence of hydrophobic and hydrophilic environments (Nagy et al., 2012). The damage to tissue by drugs can be averted with the delivery of the drug, by controlled drug release. With the systems of drug delivery, larger clearance of the drug from the entire body can be decreased by modifying the pharmacokinetics of the drug. The possible nano drugs will function by very precise and well-understood mechanisms; the major impact of nanoscience and nanotechnology will be in the foremost development of entirely novel drugs with more valuable behavior and fewer side effects (Sharaf et al., 2014). Therefore, nanoparticles are auspicious tools for the development of drug delivery, as bioimaging and diagnostic sensors. The bio-distribution of nanoparticles is still unsatisfactory because of the complex reactions of hosts to micro-and nano-sized materials and trouble in targeting particular organs in a body. Struggles are made to enhance and better comprehend the limitations and potential of nanoparticulate systems. In excretory system

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research of rats, dendrimers are captured for drug delivery of the positivelycharged Au nanoparticles, which were discovered to enter kidneys whereas negatively-charged Au nanoparticles stayed in the vital organs like the liver and spleen (Nikalje, A. P. (2015). The +ve surface charge of nanoparticles reduces the opsonization rate of nanoparticles in a liver, therefore distressing the excretory pathway. Because of the small size of five nanometers, nanoparticles can normally get stored in peripheral tissues, and thus can get gathered in the entire body over time. Therefore, nanoparticles can be utilized efficiently and successfully for distribution and targeting, further study can be conducted on nano-toxicity so that the medical applications can be improved and increased (Minchin, 2008; Sahle et al., 2019). Abraxane, is the albumin-bound paclitaxel, a nanoparticle utilized for the treatment of NSCLC (non-small-cell lung cancer) and breast cancer. Nanoparticles are utilized for drug delivery with improved efficiency for the treatment of neck and head cancer, in a rat model study, which was conducted at the University of Texas MD Anderson Cancer Center. The stated treatment utilizes Cremophor EL which permits the hydrophobic paclitaxel to be carried intravenously. When the poisonous Cremophor is substituted with the carbon nanoparticles, side effects are diminished, and the drug targeting was enhanced and requires a lower dose of toxic paclitaxel (Hollmer, 2012). The chain of nanoparticles was utilized to transport the drug doxorubicin to the breast cancerous cells in the mice study carried out at the Case Western Reserve University. A 100 nanometers long chain of nanoparticles was prepared by scientists by chemically associating three magnetic, iron oxide nanospheres, to 1 doxorubicin-loaded liposome. After dissemination of nano chains within the tumor, the magnetic nanoparticles were vibrated by producing a radiofrequency field which occasioned the breakage of liposomes, thus dispersing the drugs in the free from all over the tumor. The growth of tumors was ceased more efficiently by nanotechnology as compared to usual treatment with the doxorubicin and is less damaging for the healthy cells (Garde, 2012; Peiris et al., 2012). PEG (Polyethylene glycol) nanoparticles transporting the payload of the antibiotics at its center were utilized to aim bacterial infection more accurately inside the entire body, as stated by scientists of the Massachusetts Institute of Technology. The particle nano delivery, containing the sub-layer of pH delicate chains of amino acid histidine, is utilized to abolish bacteria that have established resistance to antibiotics due to the directed high dose

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and prolonged drug release. Nanotechnology can be proficiently used to treat several infectious diseases (Reddy, 2009). Researchers at Harvard University Wyss Institute have utilized the biomimetic approach in the mouse model. The nanoparticles coated with the drug were utilized to dissolve the blood clots by particularly binding to the tightened sections in the blood vessels just like the platelets do (RadovicMoreno et al., 2012). The biodegradable nanoparticle groups were coated with tPA (tissue plasminogen activator), were vaccinated intravenously, which hold together and degrade the clots of blood. Because of shear stresses in a vessel narrowing section, dissociation of the masses takes place and discharges the tPA-covered nanoparticles. The nanotherapeutics can generally be applied to decrease the bleeding, usually found in the treatment of standard thrombosis (Korin et al., 2015). The researchers at the University of Kentucky have developed X-shaped ribonucleic acid nanoparticles, which generally can carry four functional modules. These thermodynamically and chemically stable molecules of RNA are capable of remaining unbroken in the body of a mouse for more than 8 hours and to battle degradation by ribonucleic acids in the bloodstream. The X-shaped ribonucleic acid can be efficiently perform diagnostic and therapeutic functions. These molecules control cellular function and gene expression and can bind the cancer cells with accuracy, because of their design (Haque et al., 2012; Nourmohammadi, 2012). Minicell nanoparticles are utilized in the initial phase of a clinical experiment for the delivery of drugs for the treatment of patients with untreatable and advanced cancer. Minicells are made from membranes of the mutant bacteria and were weighted down with paclitaxel and then coated with antibodies, cetuximab, and utilized for the treatment of the multiplicity of cancers. The cells of the tumor overcome the minicells. The anti-cancer drug damages the tumor cells once it reaches the tumor. The larger size of the minicells plays an improved profile in the side effects. The system of minicell drug delivery utilizes lower drug doses and has fewer side effects and can be utilized to treat various cancers with dissimilar anti-cancer drugs (Mane, 2016; Khan et al., 2020). Nano sponges are vital tools in the delivery of the drug, because of the porous nature and small size they can hold together weakly-soluble drugs within the matrix and enhance the bioavailability. They can carry drugs to particular sites, therefore helping to avert protein and drug degradation, and can extend drug release in a controlled manner (Ahmed et al., 2013).

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1.6.2. Peptides and Proteins Delivery Peptides and proteins are macromolecules generally known as biopharmaceuticals. These macromolecules have been recognized for the treatment of several disorders and diseases as they exert various biological actions in the human body. Nanomaterials such as dendrimers and nanoparticles are known as nano biopharmaceuticals, are utilized for targeted or controlled delivery (Yezdani et al., 2018).

1.7. APPLICATIONS Nanoparticles were found to be valuable in transporting the myelin antigens, which persuade immune tolerance in the mouse model with deteriorating several scleroses. In this method, biodegradable polystyrene microparticles covered with myelin sheath peptides will retune the immune system (IS) of mice and therefore avoid the reappearance of disease and decrease the signs of the protecting myelin sheath forms covering on the nerve fibers of the central nervous system (CNS). This technique of treatment can be utilized in the treatment of several other autoimmune diseases (Getts et al., 2012; Laurance, 2012).

1.7.1. Cancer Because of their smaller size, nanoparticles can normally be of great utilization in oncology, mainly in imaging. Nanoparticles, like QDs, with the quantum confinement properties, like size-tunable emission of light, can be utilized in conjunction with magnetic resonance imaging (MRI), to yield exceptional images of the sites of tumor. As compared to the organic dyes, nanoparticles are brighter and require one source of light for excitation. Therefore, the utilization of glowing QDs might produce a higher contrast picture and at a lower cost as compared to the organic dyes utilized as contrast media. But the QDs are normally made of quite poisonous elements (Xu et al., 2013). Nanoparticles have the unique property of a high ratio of surface area to volume, which permits several functional groups to get fixed to the nanoparticle and therefore bind to particular tumor cells. Moreover, the 10– 100 nanometers small size of the nanoparticles, permits them to preferentially gather at the sites of the tumor as the tumors lack an efficient system of lymphatic drainage. Multifunctional nanoparticles can generally be made that would perceive, image, and treat the tumor in the future treatment

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of cancer (Nie et al., 2007). Kanzius RF therapy bestows microscopic nanoparticles to the cancer cells and then cooks tumors with the body with RF waves that just heat the nanoparticles and neighboring (cancerous) cells (Diebold and Calonge, 2010). Nanowires are utilized to make sensor experimental chips, which can generally identify proteins and the other biomarkers left by the cancer cells, and perceive and make a diagnosis of cancer feasible in the initial stages from a single drop of the patient’s blood (Zheng et al., 2005). Nano technology-centered drug delivery is grounded upon three facts: (a) effective encapsulation of drugs, (b) effective delivery of the drugs to the targeted portion of the body, and (c) successful discharge of the drug at that portion. Nanoshells of 120 nanometers diameter, covered with gold (Au) were utilized to destroy cancer tumors in mice at Rice University by Prof. Jennifer in 2012. The nanoshells are directed to bond with the cancerous cells by conjugating peptides or antibodies to the nanoshell surface. The area of the tumor is irradiated with the infrared laser, which usually heats the gold adequately and destroys the cancer cells (Loo et al., 2004). The nanoparticles of cadmium selenide in the shape of QDs are utilized in revealing cancer tumors since when exposed to UV (ultraviolet) light, they glow. These QDs are injected into cancer tumors by surgeons and can observe the glowing tumor, therefore the tumor can be removed easily (Yan et al., 2020). Nanoparticles are utilized in cancer photodynamic therapy, in which the particle is injected inside the tumor in a body and is brightened with the photo light from outside. The particle then absorbs the light, and if the particle is of metal, it will get warmed because of the energy from light. High energy molecules of oxygen are produced because of light which reacts chemically with and damages cells of the tumor, without reacting with the other body cells. This therapy has gained significance as a noninvasive method for handling tumors (Pontillo and Detsi, 2019). The applications of several nanosystems in cancer therapy are given as follows (Nahar et al., 2006): •

Carbon Nanotubes (CNTs): 0.5 to 3 nanometers in diameter and 20 to 1000 nanometers in length are utilized for detection of deoxyribonucleic acid (DNA) mutation and recognition of the disease protein biomarker.

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•

• •

• •

•

Dendrimers: Less than 10 nanometers in size are beneficial for controlled drug delivery discharge and as the image contrast agents. Nanocrystals: Of 2 to 9.5 nanometers size cause enhanced formulation for the poorly-soluble drugs. Nanoparticles: are of 10 to 1000 nanometers size and are utilized in ultrasound and MRI image contrast agents and also for targeted delivery of the drug, as permeation savories, and as reporters of angiogenesis, apoptosis. Nanoshells: find usage in deep tissue thermal ablation and tumorspecific imaging. Nanowires: These are beneficial for the disease protein biomarker recognition, DNA mutation recognition, and gene expression detection. Quantum Dots (QDs): 2 to 9.5 nanometers in size, can assist in optical recognition of proteins and genes in cell assays and animal models, lymph, and tumor node visualization.

1.7.2. Nanotechnology in the Cure of Neurodegenerative Disorders One of the vital uses of nanotechnology is in the treatment of neurodegenerative syndromes (Wong et al., 2012). For the CNS therapeutics, several nanocarriers like dendrimers, nanoemulsions, nano gels, liposomes, lipid nanoparticles, nanosuspensions, and polymeric nanoparticles have been studied. Carrying of the nanomedicines has normally been affected across several in vivo BBB (Blood- Brain barrier) and in vitro models by transcytosis or endocytosis, and initial preclinical achievement for the controlling of CNS conditions like, AD, HIV encephalopathy, acute ischemic stroke, and brain tumors has become feasible. Nanomedicine can normally be developed further by enhancing the BBB permeability and decreasing the neurotoxicity (Figure 1.7).

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Figure 1.7: Delivery of the nanomedicine to the central nervous system via BBB. Source: https://www.researchgate.net/figure/Delivery-of-nano-medicine-toCNS-through-BBB_fig5_274837597.

1.7.2.1. Parkinson’s Disease (PD) This can enhance current therapy of PD. PD is the 2nd most usual neurodegenerative disease after AD and disturbs 1 in every 100 persons over the age of 65, PD is the disease of the CNS (Nikalje, A. P. 2015); the neuroinflammatory responses are included and leads to serious difficulties with the motions of the body. The current-day therapies intend to enhance the functional capacity of the patient but cannot alter the progression of the neurodegenerative process (Sportelli et al., 2016). The objective of applied nanotechnology is neuroprotection and regeneration of the CNS and will considerably help from fundamental nanotechnology research carried out in parallel with progress in neuropathology, cell biology, and neurophysiology. The struggles are taken to establish new technologies that indirectly or directly aid in giving neuroprotection or a permissive environment and the active signaling signs for guided growth of axon. To lessen the peripheral side-effects of the traditional forms of PD therapy, research is engrossed in the design, optimization, and biometric simulation of an intracranial NESD (nanoenabled scaffold device) for a site-specific dopamine delivery to the brain, as an approach. Peptidic nanoparticles and peptides are fresher tools for several CNS diseases (Hou et al., 2021). Nanotechnology will generally play the main role in evolving new therapeutic and diagnostic tools. Nanotechnology might give devices

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to restrict and reverse the neuropathological disease states, in order to support and encourage functional regeneration of the damaged neurons, to give neuroprotection, and also to facilitate drug delivery. For the CNS therapeutics delivery, several nanocarriers like dendrimers, nanoemulsions, nano gels, liposomes, solid lipid nanoparticles (SLNs), nanosuspensions, and polymeric nanoparticles have been studied.

1.7.2.2. Alzheimer’s Disease (AD) Globally, around 35 million people are disturbed by AD, which is the utmost usual form of dementia. Nanotechnology discovers substantial applications in neurology. The approaches are centered on the initial AD diagnosis and cure is made feasible by scheming and engineering of the plethora of nanoparticulate objects having high specificity for the brain capillary endothelial cells. NPs (Nanoparticles) possess a high affinity for circulating amyloid-β forms and thus might induce a sink effect and enhance the condition of AD. In-vitro diagnostics for AD have advanced because of ultrasensitive NP-centered bio-barcodes and the immune sensors, along with scanning tunneling microscopy (STM) processes capable of detecting Aβ1–42. And Aβ1–40. The current research on the utilization of nanoparticles in the diagnosis of AD is as displayed in Figure 1.8 (Brambilla et al., 2011).

Figure 1.8: Nanomaterials (NMs) as contrast agents for the diagnosis of AD (Alzheimer’s disease). Source: https://www.futuremedicine.com/doi/10.2217/nnm-2019-0316.

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1.7.2.3. Tuberculosis (TB) Treatment TB is a lethal infectious disease. The lengthy treatment and the burden of pills can hinder the lifestyle of the patient and the outcome in the growth of MDR (multi-drug-resistant) strains. TB in children establishes a major issue. There is commercial non-accessibility of first-line drugs in the pediatric form. New antibiotics can be made to overcome the resistance of drugs, cut short the span of the treatment course, and decrease drug interactions with antiretroviral therapies. Nanotechnology is amongst the most promising methods for the growth of more compliant and effective medicines. The developments in nano-based systems of drug delivery for encapsulation and discharge of the anti-Tuberculosis (TB) drugs can lead to the development of more efficient and affordable TB pharmacotherapy (Islam, 2012).

1.7.3. The Clinical Uses of Nanotechnology in the Operative Dentistry Nanotechnology intends at the making and usage of devices and materials at the molecular and atomic level, the supramolecular structures, and also in the exploitation of exclusive properties of particles having a size in the range of 0.1–100 nanometers. Nano-filled resin materials are thought to provide excellent strength, wear resistance, and eventual esthetics because of their excellent luster retention and polishability. Inoperative dentistry, nanofillers institute spherical SiO2 (silicon dioxide) particles having an average size of 5 to 40 nanometers. The real novelty regarding nanofillers is the probability of enhancing the inorganic phase load. The effect of high filler load is broadly documented in terms of their mechanical properties. The microhybrid composites having an extra load of Nanofillers are the finest choice in operative dentistry. It is anticipated that in the future, it will be feasible to utilize filler material in operative dentistry, whose composition and shape would strictly mimic the mechanical and optical characteristics of natural hard tissues. It also clarifies the basic notions of fillers in the composite resins, energy dispersive spectroscopy evaluation and scanning electron microscopy (SEM), and the filler weight content. The nanocomposite resins are generally non-agglomerated distinct nanoparticles that are distributed homogeneously in coatings or resins to yield nanocomposites that have been manufactured successfully by the nano products Corporation. These nanocomposites possess superior hardness, modulus of elasticity, flexural strength, reduced polymerization shrinkage, and have outstanding handling properties (Freitas, 2005; Sivaramakrishnan and Neelakantan, 2014).

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1.8. APPLICATIONS IN OPHTHALMOLOGY The objective of nanomedicine is to monitor, govern, create, repair, defense, and enhance the human biological systems at the molecular level, with the assistance of nanostructures and nanodevices that operate tremendously in parallel at the unit cell level, to accomplish medical benefit. Principles of nanotechnology are made practical to nanomedicine like pseudo intelligence and biomimicry. Some applications of nanotechnology to ophthalmology are the treatment of oxidative stress; theragnostic; measurement of the intraocular pressure; utilization of nanoparticles for the treatment of choroidal new vessels, to avoid scars after the glaucoma surgery, and for the treatment of retinal degenerative disease utilizing gene therapy; regenerative nanomedicine; and prosthetics. The present therapeutic trials in the delivery of drugs, and postoperative disfiguring will be transformed with the assistance of nanotechnology and will aid in several unsolved problems like sight-restoring therapy for patients with a retinal degenerative disease (Figure 1.9) (Zarbin et al., 2013).

Figure 1.9: Schematics of different nanotechnology-based drug delivery systems. Source: https://clinicalgate.com/nanomedicine-in-ophthalmology/.

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Treatments for ophthalmic diseases are anticipated in this developing field. A new NDEO (nanoscale dispersed eye ointment) for the treatment of acute evaporative dry eye has been developed successfully (Zhang et al., 2014). The excipients utilized as semisolid lipids were lanolin and petrolatum, as utilized in the conventional eye ointment, which was joined with MCT (medium-chain triglycerides) as the liquid lipid; both of the phases were then disseminated in the polyvinyl pyrrolidone solution to form nanodispersion. A transmission electron micrograph exhibited that the liniment matrix was captured in the nanoemulsion of MCT, with a mean particle size of around 100 nm. The improved preparation of the NDEO was stable when kept for 6 months at 4°C, and revealed no cytotoxicity to the human corneal epithelial cells when matched with the commercial polymer-based artificial tears. The therapeutic effects of NDEO were evaluated and validated therapeutic enhancement, tending to positive association with higher concentrations of the ointment matrix in NDEO preparations compared to the marketed product. Histological evaluation validated that the NDEO returned the normal conjunctival morphology and normal corneal and is harmless for ophthalmic application. Recent research displays applications of several nanoparticulate systems such as microemulsions, nanosuspensions, liposomes, niosomes, nanoparticles, cyclodextrins, and dendrimers in the area of ocular delivery of drug and also represents how the several upcoming of nanotechnologies such as nanodiagnostics, nanomedicine, and nanoimaging can be used to discover the frontiers of ocular delivery of drug and therapy (Sahoo et al., 2008).

1.8.1. Surgery In the technique made by Rice University in 2015, two pieces of meat of the chicken are fused by the flesh welder, by placing two pieces of chicken meat touching each other. In this method, a green liquid comprising goldcoated nanoshells is permitted to dribble along with the layer, and two sides are weld together. This method can be utilized for arteries that usually have been cut during organ transplants. The flesh welder can be utilized to weld the artery flawlessly (Gobin et al., 2005).

1.8.2. Visualization The distribution of drugs and their metabolism can be concluded by tracking movement. Cells were colored by scientists to track their movement all over the body. These dyes are activated by light of a particular wavelength to

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glow. Luminescent tags were utilized to dye several numbers of cells. These tags are QDs fixed to proteins that infiltrate cell membranes. The dots were of numerous sizes and bio-inert material. As an outcome, sizes are chosen so that the light frequency utilized to make the group of QDs fluoresce and utilized to make one other group incandesce. Therefore, both groups can normally be lit with a single light source.

1.8.3. Tissue Engineering (TE) In this field, nanotechnology can be made practical to repair or reproduce damaged tissues. By utilizing appropriate nanomaterial-based scaffolds and the growth factors, unnatural stimulated cell proliferation, in the transplant of organs or artificial transplants therapy, this technology can be helpful, which can cause extension of life (Figure 1.10).

Figure 1.10: Application of nanotechnology in tissue engineering. Source: https://www.sciencedirect.com/science/article/pii/ S097469431300100X.

1.8.4. Antibiotic Resistance Antibiotic resistance can be reduced by the utilization of nanoparticles in combination therapy. Zinc oxide (ZnO) nanoparticles can reduce antibiotic resistance and improve the antibacterial activity of the ciprofloxacin against microorganisms by inhibiting several proteins that are interrelating in the pharmacologic mechanisms of drugs or antibiotic resistance (Banoee et al., 2010).

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1.8.5. Immune Response The nanodevice bucky-balls have been utilized to change the immune/ allergy response. They stop mast cells from discharging histamine into the tissues and blood, as these bind to the free radicals better than any other antioxidant available, like vitamin E (Abraham, 2010).

1.8.6. Nanopharmaceuticals Nanopharmaceuticals can be utilized to detect diseases at the initial stages, and the diagnostic uses could build upon conventional processes using nanoparticles. Nano pharmaceutical is a developing field where the drug particle sizes or the therapeutic delivery system function at the nanoscale. Delivering a suitable dose of a specific active agent to a particular disease site remains problematic in the pharmaceutical industry. Nanopharmaceuticals have massive potential in addressing the failure of traditional therapeutics, which provides site-specific targeting of the active agents. Nanopharmaceuticals can decrease toxic systemic side effects, thus occasioning better patient compliance (Figure 1.11) (Salunkhe and Nayak, 2012).

Figure 1.11: Examples of different nanopharmaceuticals. Source: https://www.researchgate.net/figure/Examples-of-nanopharmaceuticals-and-their-potential-use-in-HIV-infection-Gold_fig2_224967778.

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1.9. APPLICATIONS OF NANOTECHNOLOGY IN ALTERED MEDICATED TEXTILES Utilizing nanotechnology fresher antibacterial cotton has generally been developed and utilized for antibacterial textiles. Developing works utilizing nanotechnology, novel improved antibacterial textiles have normally been developed. Applications of traditional antimicrobial agents to the textiles have been reported. This method has been progressed by an emphasis on the inorganic nano-structured materials that attain good antibacterial activities and applications of the materials to textiles (Fouda et al., 2013).

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REFERENCES 1.

Abiodun-Solanke, I. M. F., Ajayi, D. M., & Arigbede, A. O., (2014). Nanotechnology and its application in dentistry. Annals of Medical and Health Sciences Research, 4(3), 171–177. 2. Abraham, S. A., (2010). Researchers Develop Bucky Balls to Fight Allergy (Vol. 1, pp. 1–27). Virginia Commonwealth University Communications and Public Relations. 3. Accomasso, L., Rocchietti, E. C., Raimondo, S., Catalano, F., Alberto, G., Giannitti, A., & Giachino, C., (2012). Fluorescent silica nanoparticles improve optical imaging of stem cells allowing direct discrimination between live and early‐stage apoptotic cells. Small, 8(20), 3192–3200. 4. Ahmed, R. Z., Patil, G., & Zaheer, Z., (2013). Nanosponges – a completely new nano-horizon: Pharmaceutical applications and recent advances. Drug Development and Industrial Pharmacy, 39(9), 1263– 1272. 5. Alexander, J. W., (2009). History of the medical use of silver. Surgical Infections, 10(3), 289–292. 6. Allen, T. M., & Cullis, P. R., (2004). Drug delivery systems: Entering the mainstream. Science, 303(5665), 1818–1822. 7. Banoee, M., Seif, S., Nazari, Z. E., Jafari-Fesharaki, P., Shahverdi, H. R., Moballegh, A., & Shahverdi, A. R., (2010). ZnO nanoparticles enhanced the antibacterial activity of ciprofloxacin against Staphylococcus aureus and Escherichia coli. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 93(2), 557–561. 8. Bertrand, N., & Leroux, J. C., (2012). The journey of a drug-carrier in the body: An anatomo-physiological perspective. Journal of Controlled Release, 161(2), 152–163. 9. Boisseau, P., & Loubaton, B., (2011). Nanomedicine, nanotechnology in medicine. Comptes Rendus Physique, 12(7), 620–636. 10. Boverhof, D. R., Bramante, C. M., Butala, J. H., Clancy, S. F., Lafranconi, M., West, J., & Gordon, S. C., (2015). Comparative assessment of nanomaterial definitions and safety evaluation considerations. Regulatory Toxicology and Pharmacology, 73(1), 137–150. 11. Brambilla, D., Le Droumaguet, B., Nicolas, J., Hashemi, S. H., Wu, L. P., Moghimi, S. M., & Andrieux, K., (2011). Nanotechnologies for Alzheimer’s disease: Diagnosis, therapy, and safety issues.

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12.

13.

14.

15.

16. 17.

18.

19. 20.

21.

22. 23.

Medical Applications of Nanomaterials

Nanomedicine: Nanotechnology, Biology and Medicine, 7(5), 521– 540. Buzea, C., & Pacheco, I., (2017). Nanomaterials and their classification. In: EMR/ESR/EPR Spectroscopy for Characterization of Nanomaterials (Vol. 1, pp. 3–45). Springer, New Delhi. Cavalcanti, A., Shirinzadeh, B., Freitas, R. A., & Hogg, T., (2007). Nanorobot architecture for medical target identification. Nanotechnology, 19(1), 015103. Choi, H., & Mody, C. C., (2009). The long history of molecular electronics: Microelectronics origins of nanotechnology. Social Studies of Science, 39(1), 11–50. Deb, K. D., Griffith, M., Muinck, E. D., & Rafat, M., (2012). Nanotechnology in stem cells research: Advances and applications. Front Biosci. (Landmark Ed), 17(1), 1747–1760. Diebold, Y., & Calonge, M., (2010). Applications of nanoparticles in ophthalmology. Progress in Retinal and Eye Research, 29(6), 596–609. Fouda, M. M., Abdel-Halim, E. S., & Al-Deyab, S. S., (2013). Antibacterial modification of cotton using nanotechnology. Carbohydrate Polymers, 92(2), 943–954. Freitas, Jr. R. A., (2005). Nanotechnology, nanomedicine and nanosurgery. International Journal of Surgery (London, England), 3(4), 243–246. Garde, D., (2012). Chemo bomb’ nanotechnology effective in halting tumors. Fierce Drug Delivery, 1, 1–42. Gebel, T., Foth, H., Damm, G., Freyberger, A., Kramer, P. J., Lilienblum, W., & Hengstler, J. G., (2014). Manufactured nanomaterials: Categorization and approaches to hazard assessment. Archives of Toxicology, 88(12), 2191–2211. Getts, D. R., Martin, A. J., McCarthy, D. P., Terry, R. L., Hunter, Z. N., Yap, W. T., & Miller, S. D., (2012). Microparticles bearing encephalitogenic peptides induce T-cell tolerance and ameliorate experimental autoimmune encephalomyelitis. Nature Biotechnology, 30(12), 1217–1224. Glezer, A. M., (2011). Structural classification of nanomaterials. Russian Metallurgy (Metally), 2011(4), 263–269. Gobin, A. M., O’Neal, D. P., Watkins, D. M., Halas, N. J., Drezek, R. A., & West, J. L., (2005). Near-infrared laser‐tissue welding using

Introduction to Nanotechnology and Its Medical Applications

24.

25.

26. 27.

28.

29.

30.

31.

32.

29

nanoshells as an exogenous absorber. Lasers in Surgery and Medicine: The Official Journal of the American Society for Laser Medicine and Surgery, 37(2), 123–129. Handy, R. D., Al-Bairuty, G., Al-Jubory, A., Ramsden, C. S., Boyle, D., Shaw, B. J., & Henry, T. B., (2011). Effects of manufactured nanomaterials on fishes: A target organ and body systems physiology approach. Journal of Fish Biology, 79(4), 821–853. Haque, F., Shu, D., Shu, Y., Shlyakhtenko, L. S., Rychahou, P. G., Evers, B. M., & Guo, P., (2012). Ultra-stable synergistic tetravalent RNA nanoparticles for targeting to cancers. Nano Today, 7(4), 245– 257. Hollmer, M., (2012). Carbon nanoparticles charge up old cancer treatment to powerful effect. Fierce Drug Delivery, 1, 1–22. Hou, J., Yang, Y., Yu, D. G., Chen, Z., Wang, K., Liu, Y., & Williams, G. R., (2021). Multifunctional fabrics finished using electro sprayed hybrid Janus particles containing nanocatalysts. Chemical Engineering Journal, 411, 128474. Hulla, J. E., Sahu, S. C., & Hayes, A. W., (2015). Nanotechnology: History and future. Human and Experimental Toxicology, 34(12), 1318–1321. Ieracitano, C., Paviglianiti, A., Mammone, N., Versaci, M., Pasero, E., & Morabito, F. C., (2021). SoCNNet: An optimized Sobel filter based convolutional neural network for SEM images classification of nanomaterials. In: Progresses in Artificial Intelligence and Neural Systems (Vol. 1, pp. 103–113). Springer, Singapore. Islam, S., (2012). Application of Nanotechnology for Wool and Wool Blends in Medical Textiles Utilizing Biopolymers (Doctoral dissertation, Vol. 1, pp. 1–22). Khan, A. U., Khan, M., Cho, M. H., & Khan, M. M., (2020). Selected nanotechnologies and nanostructures for drug delivery, nanomedicine, and cure. Bioprocess and Biosystems Engineering, 43(8), 1339–1357. Korin, N., Gounis, M. J., Wakhloo, A. K., & Ingber, D. E., (2015). Targeted drug delivery to flow-obstructed blood vessels using mechanically activated nanotherapeutics. JAMA Neurology, 72(1), 119–122.

30

Medical Applications of Nanomaterials

33. Kubik, T., Bogunia-Kubik, K., & Sugisaka, M., (2005). Nanotechnology on duty in medical applications. Current Pharmaceutical Biotechnology, 6(1), 17–33. 34. Lanone, S., & Boczkowski, J., (2006). Biomedical applications and potential health risks of nanomaterials: Molecular mechanisms. Current Molecular Medicine, 6(6), 651–663. 35. Laurance, J., (2012). Scientists develop nanoparticle method to help tackle major diseases. The Independent, 11, 12. 36. Lavan, D. A., McGuire, T., & Langer, R., (2003). Small-scale systems for in vivo drug delivery. Nature Biotechnology, 21(10), 1184–1191. 37. Leon, L., Chung, E. J., & Rinaldi, C., (2020). A brief history of nanotechnology and introduction to nanoparticles for biomedical applications. In: Nanoparticles for Biomedical Applications (Vol. 1, pp. 1–4). Elsevier. 38. Loo, C., Lin, A., Hirsch, L., Lee, M. H., Barton, J., Halas, N., & Drezek, R., (2004). Nanoshell-enabled photonics-based imaging and therapy of cancer. Technology in Cancer Research and Treatment, 3(1), 33–40. 39. Mane, A. S., (2016). Role of nanotechnology in medicine and health. Magna Carta, 169, 1–44. 40. McIntyre, R. A., (2012). Common nanomaterials and their use in real world applications. Science Progress, 95(1), 1–22. 41. Minchin, R., (2008). Sizing up targets with nanoparticles. Nature Nanotechnology, 3(1), 12, 13. 42. Nagy, Z. K., Balogh, A., Vajna, B., Farkas, A., Patyi, G., Kramarics, Á., & Marosi, G., (2012). Comparison of electrospun and extruded soluplus®-based solid dosage forms of improved dissolution. Journal of Pharmaceutical Sciences, 101(1), 322–332. 43. Nahar, M., Dutta, T., Murugesan, S., Asthana, A., Mishra, D., Rajkumar, V., & Jain, N. K., (2006). Functional polymeric nanoparticles: An efficient and promising tool for active delivery of bio-actives. Critical Reviews™ in Therapeutic Drug Carrier Systems, 23(4), 1–55. 44. Nasrollahzadeh, M., Sajadi, S. M., Sajjadi, M., & Issaabadi, Z., (2019). An introduction to nanotechnology. In: Interface Science and Technology (Vol. 28, pp. 1–27). Elsevier. 45. Nie, S., Xing, Y., Kim, G. J., & Simons, J. W., (2007). Nanotechnology applications in cancer. Annu. Rev. Biomed. Eng., 9, 257–288.

Introduction to Nanotechnology and Its Medical Applications

31

46. Nourmohammadi, N., (2012). A new study shows promise in using RNA nanotechnology to treat cancers and viral infections. Nanomedicine: Notes, Fierce Drug Delivery, 1, 1–20. 47. Ochekpe, N. A., Olorunfemi, P. O., & Ngwuluka, N. C., (2009). Nanotechnology and drug delivery part 1: Background and applications. Tropical Journal of Pharmaceutical Research, 8(3), 1–33. 48. Peiris, P. M., Bauer, L., Toy, R., Tran, E., Pansky, J., Doolittle, E., & Karathanasis, E., (2012). Enhanced delivery of chemotherapy to tumors using a multicomponent nanochain with radio-frequency-tunable drug release. ACS Nano, 6(5), 4157–4168. 49. Pontillo, A. R. N., & Detsi, A., (2019). Nanoparticles for ocular drug delivery: Modified and non-modified chitosan as a promising biocompatible carrier. Nanomedicine, 14(14), 1889–1909. 50. Qu, X., Alvarez, P. J., & Li, Q., (2013). Applications of nanotechnology in water and wastewater treatment. Water Research, 47(12), 3931– 3946. 51. Radovic-Moreno, A. F., Lu, T. K., Puscasu, V. A., Yoon, C. J., Langer, R., & Farokhzad, O. C., (2012). Surface charge-switching polymeric nanoparticles for bacterial cell wall-targeted delivery of antibiotics. ACS Nano, 6(5), 4279–4287. 52. Reddy, S. J., (2009). The recent advances in the nanotechnology and its applications: A review. Nanotechnology, 50, 5. 53. Romig, Jr. A. D., Baker, A. B., Johannes, J., Zipperian, T., Eijkel, K., Kirchhoff, B., & Walsh, S., (2007). An introduction to nanotechnology policy: Opportunities and constraints for emerging and established economies. Technological Forecasting and Social Change, 74(9), 1634–1642. 54. Sahle, F. F., Kim, S., Niloy, K. K., Tahia, F., Fili, C. V., Cooper, E., & Lowe, T. L., (2019). Nanotechnology in regenerative ophthalmology. Advanced Drug Delivery Reviews, 148, 290–307. 55. Sahoo, S. K., Dilnawaz, F., & Krishnakumar, S., (2008). Nanotechnology in ocular drug delivery. Drug Discovery Today, 13(3, 4), 144–151. 56. Salunkhe, P. R., & Nayak, S. S., (2012). Microbial synthesis of silver nanoparticles and their applications in medical textiles. Manmade Textiles in India, 40(5), 1–33.

32

Medical Applications of Nanomaterials

57. Seil, J. T., & Webster, T. J., (2012). Antimicrobial applications of nanotechnology: Methods and literature. International Journal of Nanomedicine, 7, 2767. 58. Sharaf, M. G., Cetinel, S., Heckler, L., Damji, K., Unsworth, L., & Montemagno, C., (2014). Nanotechnology-based approaches for ophthalmology applications: Therapeutic and diagnostic strategies. The Asia-Pacific Journal of Ophthalmology, 3(3), 172–180. 59. Silva, G. A., (2004). Introduction to nanotechnology and its applications to medicine. Surgical Neurology, 61(3), 216–220. 60. Sivaramakrishnan, S. M., & Neelakantan, P., (2014). Nanotechnology in dentistry-what does the future hold in store. Dentistry, 4(2), 1. 61. Smith, D. M., Simon, J. K., & Baker, Jr. J. R., (2013). Applications of nanotechnology for immunology. Nature Reviews Immunology, 13(8), 592–605. 62. Solaiman, S. M., Yamauchi, Y., Kim, J. H., Horvat, J., Dou, S. X., Alici, G., & Hossain, M. S. A., (2017). Nanotechnology and its medical applications: Revisiting public policies from a regulatory perspective in Australia. Nanotechnology Reviews, 6(3), 255–269. 63. Soni, N. R., (2016). Recent progress on transfection by using nanotechnology nanomedicines. TFP: Pharmaceutical Sciences, 1(3), 1–22. 64. Sportelli, M. C., Picca, R. A., Ronco, R., Bonerba, E., Tantillo, G., Pollini, M., & Cioffi, N., (2016). Investigation of industrial polyurethane foams modified with antimicrobial copper nanoparticles. Materials, 9(7), 544. 65. Stone, V., Nowack, B., Baun, A., Van, D. B. N., Von, D. K. F., Dusinska, M., & Fernandes, T. F., (2010). Nanomaterials for environmental studies: Classification, reference material issues, and strategies for Physico-chemical characterization. Science of the Total Environment, 408(7), 1745–1754. 66. Subedi, S. K., (2014). An introduction to nanotechnology and its implications. Himalayan Physics, 5, 78–81. 67. Sudha, P. N., Sangeetha, K., Vijayalakshmi, K., & Barhoum, A., (2018). Nanomaterials history, classification, unique properties, production and market. In: Emerging Applications of Nanoparticles and Architecture Nanostructures (Vol. 1, pp. 341–384). Elsevier.

Introduction to Nanotechnology and Its Medical Applications

33

68. Tonelli, F. M., Goulart, V. A., Gomes, K. N., Ladeira, M. S., Santos, A. K., Lorençon, E., & Resende, R. R., (2015). Graphene-based nanomaterials: Biological and medical applications and toxicity. Nanomedicine, 10(15), 2423–2450. 69. Toumey, C. P., (2008). Reading Feynman into nanotechnology: A text for a new science. Techné: Research in Philosophy and Technology, 12(3), 133–168. 70. Wang, A. Z., Yuet, K., Zhang, L., Gu, F. X., Huynh-Le, M., RadovicMoreno, A. F., & Farokhzad, O. C., (2010). ChemoRad nanoparticles: A novel multifunctional nanoparticle platform for targeted delivery of concurrent chemoradiation. Nanomedicine, 5(3), 361–368. 71. Wang, Z., Ruan, J., & Cui, D., (2009). Advances and prospect of nanotechnology in stem cells. Nanoscale Research Letters, 4(7), 593– 605. 72. West, J. L., & Halas, N. J., (2000). Applications of nanotechnology to biotechnology: Commentary. Current Opinion in Biotechnology, 11(2), 215–217. 73. Wohlleben, W., (2012). Validity range of centrifuges for the regulation of nanomaterials: From classification to as-tested coronas. Journal of Nanoparticle Research, 14(12), 1–18. 74. Wong, H. L., Wu, X. Y., & Bendayan, R., (2012). Nanotechnological advances for the delivery of CNS therapeutics. Advanced Drug Delivery Reviews, 64(7), 686–700. 75. Xu, Q., Kambhampati, S. P., & Kannan, R. M., (2013). Nanotechnology approaches for ocular drug delivery. Middle East African Journal of Ophthalmology, 20(1), 26. 76. Yan, D., Yao, Q., Yu, F., Chen, L., Zhang, S., Sun, H., & Fu, Y., (2020). Surface modified electrospun poly (lactic acid) fibrous scaffold with cellulose nanofibrils and Ag nanoparticles for ocular cell proliferation and antimicrobial application. Materials Science and Engineering: C, 111, 110767. 77. Yezdani, U., Khan, M. G., Kushwah, N., Verma, A., & Khan, F., (2018). Application of nanotechnology in diagnosis and treatment of various diseases and its future advances in medicine. World Journal of Pharmacy and Pharmaceutical Sciences, 7(11), 1611–1633. 78. Yousaf, S. A., & Salamat, A., (2011). Effect of heating environment on fluorine-doped tin oxide (f: SnO/sub-2/) thin films for solar cell

34

79.

80.

81.

82.

Medical Applications of Nanomaterials

applications. In: Proceedings of the International Conference on Power Generation Systems Technologies (Vol. 1, pp. 1–33). Zarbin, M. A., Montemagno, C., Leary, J. F., & Ritch, R., (2010). Nanotechnology in ophthalmology. Canadian Journal of Ophthalmology, 45(5), 457–476. Zarbin, M. A., Montemagno, C., Leary, J. F., & Ritch, R., (2013). Nanomedicine for the treatment of retinal and optic nerve diseases. Current Opinion in Pharmacology, 13(1), 134–148. Zhang, W., Wang, Y., Lee, B. T. K., Liu, C., Wei, G., & Lu, W., (2014). A novel nanoscale-dispersed eye ointment for the treatment of dry eye disease. Nanotechnology, 25(12), 125101. Zheng, G., Patolsky, F., Cui, Y., Wang, W. U., & Lieber, C. M., (2005). Multiplexed electrical detection of cancer markers with nanowire sensor arrays. Nature Biotechnology, 23(10), 1294–1301.

CHAPTER

2

FUNCTIONALIZATION AND BIOCOMPATIBILITY OF NANOMATERIALS

CONTENTS 2.1. Introduction....................................................................................... 36 2.2. Conversion of Nanomaterial Into Water-Soluble Form....................... 37 2.3. NM Bioconjugation........................................................................... 51 2.4. Applications of Biocompatible Nanomaterials................................... 60 References................................................................................................ 69

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2.1. INTRODUCTION Amongst the most significant experiments in the medical uses of NMs (nanomaterials) is the surface modification that permits functionalization and biocompatibility. Efficient surface modifications along with highly organized surface conjugation approaches are required to incorporate particular biomolecules inside or on the surface of nanomaterials. However, achievement in functionalization is dependent on several factors that comprise NMs’ size, charge, shape, surface modification, and chemistry. These factors are frequently difficult to change individually, so the factor’s contribution is hard to generalize (Zhang et al., 1996; Jenekhe et al., 1997). The NMs with small sizes that touch the atomic level, more frequently than not, nullify the governing principles at the macroscopic level comprising these chemicals. At the nanometer scale, the quantum mechanical effects start to appear, leading to unexpected and varied physicochemical properties (Clark et al., 2000; Manandhar et al., 2003). Therefore, modeling and indirect approaches are often employed to precisely examine the complex interactions and properties of the materials at the nanoscale. It is vital to observe that these new and exclusive properties empower nanotechnology, precisely for nanomedicine, to offer powerful solutions to several problems. With the institution of STM (scanning tunneling microscopy) in the 1980s, the management of distinct atoms became feasible, considerably contributing to the quick discovery and expansion of fullerenes, carbon nanotubes (CNTs), and the semiconductor QDs (quantum dots) (Binnig et al., 1985; Soler et al., 1986). The core QDs are normally made in the high-temperature solvents that frequently involve the mixture of trioctylphosphine oxide and trioctylphosphine (TOPO/ TOP) followed by the layer of broad-bandgap semiconductor materials that normally can be covered on the surface of quantum dot shell/core. These QDs are utilized as the hydrophobic nanocrystals and are made soluble tinwater by ligand interchange or by adsorption of the heterobifunctional organic covering on the quantum dot surface. A comprehensive analysis by Uyeda et al. (2005) reviews the group of substances that offer the functionality to the quantum dot surface.. These comprise silanes/silanols, thiols, bidentate thiols, oligomeric phosphines, amine box dendrimers, phosphatidyl compounds, proteins, and peptides, and amphiphilic saccharides. In an analogous manner, IOMNPs (iron oxide magnetic nanoparticles) and the other magnetic nanoparticles can usually be altered like the QDs in order to make these nanoparticles biocompatible. This

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chapter provides a discussion of several ways of altering the nanomaterial surface in order to make NM water-soluble and eventually biocompatible (Curl and Smalley, 1988; Rao et al., 2001).

2.2. CONVERSION OF NANOMATERIAL INTO WATER-SOLUBLE FORM Most NMs (nanomaterials) including QDs, IOMNPs, and silver or gold NPs (nanoparticles) are normally synthesized in the nonpolar organic solvents. Generally, nanomaterial synthesis utilizes long-chain ligands like OA (oleic acid) (C18) to control particle growth and nucleation. However, an OA capping introduces the 2-nanometers thick tunneling obstacle on nanomaterials that is harmful to applications that are dependent on the transfer of charge (Alivisatos, 1992; Murray et al., 1993). To make these beneficial for medical and biological applications, they must be converted into the water-soluble form by substituting hydrophobic surface ligands with the amphiphilic ligands. Different nanomaterial water solubilization procedures have been established over the last few years. These are: (a) exchange of ligand with simple thiol-comprising molecules or more advanced ones like oligomeric phosphines, dendrons, and peptides, and (b) encapsulation by the layer of triblock copolymers or amphiphilic diblock or in polymer shells, silica shells, amphiphilic polysaccharides, or phospholipid micelles, and (c) amalgamation of layers of dissimilar molecules (Voura et al., 2004; Stroh et al., 2005). Nanoparticle surface modification is frequently necessary for particular applications. Whereas QDs synthesized in the organic solvents incline to have much higher quality because of the lower density of the surface trap states causing higher PL (photoluminescence) produce, their hydrophobic surfaces are not compatible with the applications that need hydrophilic surfaces like several medical applications. To convert hydrophobic into hydrophilic surfaces, numerous approaches have been established (Manna et al., 2000; Peng and Peng, 2001). Three kinds of modifications are discussed here in the chapter, which includes silanization, ligand exchange, and surface coating utilizing amphiphilic polymers or surfactants like phospholipids. All of these approaches for surface modification outcome in the surfacefunctionalized water-soluble NS (nanostructures) (Figure 2.1) (Hines and Guyot-Sionnest, 1996; Qu and Peng, 2002).

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Figure 2.1: Diagram of transforming hydrophobic nanomaterials to hydrophilic nanomaterials loaded with the drug. Source: https://www.sciencedirect.com/science/article/pii/ B9780123850898000030.

For fluorescent labeling or tagging of appropriate molecules for biological and medical applications, it is necessary to have water-soluble QDs and other nanoparticles with stable physical, magnetic, optical, and/or electrical properties that are not affected by environmental factors. High-quality QDs, IOMNPs, and the other nanomaterials are frequently synthesized under the high-temperature organometallic circumstances, and are not compatible with the biological systems (Xing and Rao, 2004; Resch-Genger et al., 2008). The chapter highlights a discussion of several approaches of surface alterations that convert nanomaterials from hydrophobic to the hydrophilic form that permits these NMs to be biocompatible and burdened with medically appropriate molecules like antibodies (Abs) or drugs or both (Figure 2.1).

2.2.1. Ligand Exchange This technique is among the approaches by which the nanomaterials surfaces are modified in order to make these NMs water-soluble for biological and medical applications. A ligand might be in the shape of an

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ion, molecule, functional group, or atom that forms the complex with a nanoparticle, creating the interface amongst the nanomaterials or shell/core and its surroundings (Figure 2.1). Ligands normally play a very vital role in numerous applications of nanomaterials that comprise interactions between the nanomaterial and the surroundings (Chan and Nie, 1998; Pellegrino et al., 2004). There exists a broad variety of ligands for nanomaterial ligand exchange, comprising hexanethiol, octadecanethiol, dodecanethiol, TOP, TOPO, triphenylphosphine, perfluorinated lauric acid, didodecylamine, OA, tri octyl aluminum, and the mixture of TOP and dodecanethiol. Amongst these, only OA and thiols outcome in upsurged air stability. The rest of the ligands precipitate nanoparticles or display indistinguishable behavior to the lauric acid. The latter might specify that no exchange took place, occasioning weaker adsorption as compared to that of the lauric acid (Mitchell et al., 1999; Willard et al., 2001). Most health-related and medical applications of nanomaterials are dependent on particular ligands, and substituting the current ligands with the other ligands is frequently a critical processing step known as ligand exchange. The exchange of ligands is normally accomplished by revealing the particles comprising the original ligands to novel ligands, which are normally present in surplus. Ligand exchange can generally be accomplished in the following techniques (Bruchez et al., 1998; Rogach et al., 2001): •

Dissolving the nanoparticles in solid form in a solution comprising the novel ligand, which is an approach utilized to functionalize InP and CdSe with pyridine (Guo et al., 2003; Kim and Bawendi, 2003). • The phase-transfer method where, for instance, the water-soluble particles are shifted to the organic phase or conversely by adding an appropriate ligand that behaves as the phase-transfer agentfor instance, dodecanethiol encourages the transferal of chargestabilized Au nanoparticles to the toluene phase or the mercapto acids have been utilized to transferal CdTe nanomaterials from the organic phase to the aqueous phase (Mitchell et al., 1999; Dubertret et al., 2006). The result of ligand-exchange procedures is difficult to evaluate except by indirect techniques like the variation in solubility or electrophoretic mobility. Confirmation is generally not a problem till the ligand-exchanged nanoparticles behave contrarily and that NPs do their job. The method of ligand exchange is amongst successful methods to assimilate functionality

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that gives versatility for several applications of nanomaterials. This method has severe effects on nanomaterials properties, especially their fluorescence or luminescence properties. For example, semiconductor nanomaterials that have engrossed light can then relax back to their ground state via luminescence and the effectiveness of this process critically depends on the surface of nanoparticles. Surface defects or the surface trap states in nanocrystal structures behave as the temporary hole for electron, averting their radiative recombination (Figure 2.2) (Sapsford et al., 2007; Mahmoudi et al., 2011).

Figure 2.2: Ligand exchange of the CuInS2 NPs (nanoparticles). Source: https://www.researchgate.net/figure/Scheme-of-the-nanoparticle-synthesis-and-ligand-exchange-with-1-hexanethiol_fig2_329149642.

The other occurrence of ion untrapping and trapping events outcomes in intermittent fluorescence that is observable at the level of single-molecule, which decreases the overall QY (quantum yield), which is the emitted/ absorbed photons ratio. To overcome these issues and to guard surface atoms against the chemical reactions and specifically oxidation, a shell comprising of a small number of atomic layers of the material having a larger bandgap is normally grown on the top of the nanocrystal core (Hans and Lowman, 2002; Jaffrezic-Renault et al., 2007). The shell can be made to improve photostability by numerous orders of magnitude as compared to the conventional dyes and simultaneously attain the QY of close to 90%. Ligands binding to the surface atoms that generally can passivate the trap states affects the luminescence effectiveness of the semiconductor nanomaterials strongly, but due to stability problems, surface state passivation with the ligands is not the way to prepare highly luminescent nanomaterials with the robust emission. Conversely, this variation in luminescence can be utilized

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to observe the ligand-nanomaterial interaction (Kim et al., 2009; Mahmoudi et al., 2010). Utilization of the bifunctional ligands that comprise one functional group that fastens at the surface of nanomaterial and the 2nd group that is revealed to surroundings is a valuable development. This is confirmed by the utilization of thiols that trigger CdSe nanomaterials adsorb at Au surfaces or by the polymeric materials like PEG that carry amine, hydroxyl, carboxyl, or the combination of both functional groups (Figure 2.1). An outstanding application is for nanomaterial sensors that are altered with the functional groups that give affinity to a particular analyte that outcomes in a variation in the optical properties of nanomaterials. One such nanomaterial prepared by Chilkoti and Nath (2002) gave gold nanomaterials (AuNMs) similarity for streptavidin via functionalization with biotin. Variations in the AuNMs plasmon resonance were utilized to specify the streptavidin’s binding to biotin. Colloidal CdSe nanomaterials were engineered via encapsulation with the amphiphilic polymer upon which the pH-subtle squaraine dye was joined (Philipse et al., 1994; Moore et al., 1997). In this nanomaterials structure, the ZnS/ CdSe nanocrystal might fluoresce or undergo FRET (fluorescence energy transfer) to squaraine dye. The efficiency of FRET in nanostructures is the function of surroundings that outcome from the absorption profile of dye which is governed by pH whereas the ratio of nanomaterial to the emission of dye is the measure of percentage hydrogen of the environment. A substitute to the long-chain ligands in preparation of the nanocrystal solids is very short bifunctional ligands, like hydrazine, forming the tightly packed nanocrystal solids that have adequate conductivity to be utilized in diverse charge-transfer applications (Xie et al., 2006; Sajja et al., 2009).

2.2.2. Thiols for the Ligand Exchange Monothiols, silanes/silanols, bidentate thiols, oligomeric phosphines, dithiothreitol, amine box dendrimers, proteins, and peptides, and amphiphilic saccharides, are utilized to prepare nanomaterials for the medical applications. For instance, CdSe nanocrystals covered with the hydrophilic deprotonated thiol ligands were studied thoroughly in the pseudo-steady-state titration and introduced for concluding the precipitation percentage hydrogen of nanocrystals covered with the electron-donating ligands (Yang et al., 2008, 2009; Xu et al., 2011). For contrast, CdS, and CdTe nanocrystals covered with the same kinds of ligands were examined. The results displayed that the precipitation of nanocrystals was triggered by the dissociation of nanocrystal-ligand organizing bonds from the surface

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of the nanocrystal. The ligands were detached from the surface because of protonation in a comparatively low percentage hydrogen range, between 2 and 7 dependents on size, roughly within the quantum captivity size regime and chemical composition of the nanocrystals. On the contrary, the redispersion of nanocrystals was discovered to be exclusively established by the deprotonation of ligands. The ligands dissociation pH dependent on size was tentatively utilized as a mean for concluding the free energy dependent on the size associated with the creation of the nanocrystal-ligand organizing bond (Zhao and Harris, 1998; Michalet et al., 2005). To resolve the instability of nanomaterials that are transformed into the water-soluble form via thiol ligand exchange, two approaches have been established. One is centered on direct adsorption of the bifunctional ligands on nanocrystal’s surface and the second approach is centered on surface coating with the layer of silica (Wu et al., 2003; Pinaud et al., 2004). Direct adsorption of the bifunctional ligands on nanocrystal’s surface is carried out utilizing ligands that possess water-soluble and organic soluble functional groups. In the procedure, the organic-soluble groups orient towards the hydrophobic nanomaterials, whereas the hydrophilic group projects away from an organic soluble section and towards an aqueous solution making the altered nanomaterial water-soluble. However, surface coating with the layer of silica encapsulates several nanomaterials inside the silica nanoparticle of 100 nanometers or greater diameter (Chan and Nie, 1998; Pathak et al., 2001). The mercaptoacetic acid is amongst the thiols utilized to make QDs water-soluble, as the mercapto percentage has a large attraction to zinc atoms, whereas the carboxylic acid (C nH 2n + 1COOH) group is hydrophilic and also reactive to biomolecules (Gao et al., 2002; Goldman et al., 2002). Conversely, this procedure causes the fluorescence QYs to drop below 10% after the water solubilization. One more problem is moderate desorption of the mercaptoacetic acid on the quantum dot’s surface frequently leads to precipitation and aggregation of the QDs. An altered version of this procedure comprises attachment of the engineered proteins to QDs via electrostatic interactions, and the utilization of dithiothreitol has generally been adopted for the stabilization and bioconjugation of the nanocrystal (Gerion et al., 2001; Gao et al., 2004). The following approach was utilized for the creation of water-soluble CdS/ CdSe/ ZnS QDs for imaging and some other biomedical applications (Matsuzaki et al., 2000; Sukhanova et al., 2004):

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•

Precipitate the organic-soluble CdS/CdSe/ZnS QDs with acetone two times to eliminate free ODA (octadecylamine) in a solution; • Re-disperse in the chloroform; • Add 40 milligrams of polyethyleneimine (PEI) to the 0.5 nmol of CdS/ CdSe /ZnS QDs in chloroform; • Shake the mixture well for two hours at room temperature; • Evaporate this solvent under argon; • Dissolve the dehydrated film in ultrapure water; • Centrifuge at 6000 g for 10 min to produce a clear supernatant having white deposits; • Dialyze with the Mw 50 kDa in order to eliminate the unrestricted PEI molecules against borate buffer solution or water; • Store at 2°C to 8°C to avert bacterially and mold pollution. Depict the water-soluble QDs with TEM (transmission electron microscopy) to establish the shape and diameter. Use the Zeta tracker to institute the hydrodynamic size and the zeta potential. Run the scan to develop the emission and absorption wavelength (Wuister et al., 2003; Michalet et al., 2005).

2.2.3. Encapsulation of Nanomaterials Encapsulation with amphiphilic triblock or diblock copolymers or in phospholipid micelles, silica shells, or the polymer shells is one more way to convert nanomaterials into the water-soluble form. The process of encapsulation introduces novel functional groups on nanomaterials surface like hydroxides, carboxylic acids, or amines (Parak et al., 2002; Ballou et al., 2004). The functional groups can normally be utilized to attach diverse biomolecules, including vaccines and drugs on the surface of the nanomaterials (Figure 2.3). Silanes have generally been utilized to functionalize semiconductor QDs, leading to several benefits. The siloxane shell provides additional stability to the nanostructures, and silanized nanosystems stay stable over the broad range of percentage hydrogen and impede the discharge of unwanted heavy elements. The process of silanization can be executed by Stöber-procedurebased methods, in which the alkoxysilanes are condensed in basic or acidic medium that inclines to the synthesis of the highly fluorescent silica-covered QDs with several surface charges by implementing the process analogous to the process of Stöber. One of the benefits of silanization is self-condensation

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amongst the molecules of silane. To overpower this, Yang and Gao (2005) engaged the reverse microemulsion approach to cover CdTe nanocrystals with silica. Several organosilanes in toluene are utilized to treat nanocrystals in order to execute multifunctionalization of the semiconductor QDs (Dabbousi et al., 1997; Lin et al., 2007). Silane, like 3-mercaptopropyltrimethoxysilane, is adsorbed directly on the nanocrystals in order to displace the molecules of TOPO and form the siloxane/silica shell on a surface by an institution of the base and hydrolysis of silanol groups. Polymerization of these silanol groups alleviates the nanocrystals against accumulation making the QDs soluble in the intermediate polar solvents, like dimethylsulfoxide and methanol. Reaction with the bifunctional methoxy compounds transforms the particles into a water-soluble form. Associated with the process of mercaptoacetic acid, polymerized siloxane-coated QDs are highly stable against accumulation. However, only mg (milligram) quantities can be made per batch utilizing this process. Moreover, this procedure leaves remaining silanol groups on the surface of the nanocrystal, which can trigger gel formation and precipitation at neutral percentage hydrogen when not removed properly (Kanninen et al., 2008).

Figure 2.3: Diagram of hydrophilic carboxyl-functionalized nanomaterials carrying the drug (left) or the drug and Ab (right). Source: https://www.sciencedirect.com/book/9780123850898/nanomaterialsfor-medical-applications.

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One procedure for the synthesis of the silica-coated nanoparticles is defined below. The procedure can be scaled up for making ZnS/ CdSe nanocrystals with sizes between 2 and 8 nanometers: • • • • • • • • •

• •

• • • • • • •

Utilize anhydrous methanol to precipitate 1 mL of nanocrystals in TOPO/butanol (OD (optical density) of nanocrystals ~2). Add 50 µL of MPS (mercaptopropyltris(methyloxy)silane) and vortex in order to mix thoroughly. Add 5 µL of TMAH (tetramethylammonium hydroxide) and mix carefully into the optically clear solution. Add 120 mL of the anhydrous methanol. Add 750 µL of TMAH to make it more basic with a pH of 10. Place in the 500 mL 3-neck-flask with the stream of N2 with slight stirring for one h. Moderately heat the solution to nearly 60°C for 30 min. Cooldown to room temperature. Add 90 mL of methanol, 10 mL of 18 MΩ water, 600 µL of the (trihydroxysilyl)propyl methyl phosphonate, and then 20 µL of MPS. Mix for nearly two h, heat to nearly 60°C for less than five min, and then cool down to almost 30°C. Quench the residual silanol groups with the mixture of 20 mL of methanol and 2 mL of the chlorotrimethylsilane to which nearly three g of solid (TMAH) pentahydrate is then added in order to make it basic. Stir for almost two h and heat back to nearly 60°C for 30 min. Store at room temperature for 2 to 4 days with continuous stirring in the N2 atmosphere. Evaporate with the rotary evaporator down to 2 to 5× less as compared to the original volume. Leave at room temperature for 24 h. Dialyze in the 10,000 MWCO (molecular-weight cutoff) dialysis tubing against the methanol for one day. Filter through the 0.45 µmeter size of pore nylon syringe filter. Remove the surplus of independent silane with the centrifugal filter devices that leave about two mL solution.

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• •

Store the two mL solution at room temperature for 12 h. Pass this solution of the silanized nanocrystals in CH3OH (methanol) through the solvent exchange column. • Only the luminous eluted fractions are gathered and filtered with the 22-µm size of the pore acetate filter. • Centrifuge at 20000 g for 30 minutes and remove the precipitate. • Store the solution in the air. • Establish the OD utilizing the coefficient of extinction as 105 M–1 cm–1. Characterize the water-soluble QDs with TEM to conclude the shape and diameter. Utilize the Zeta tracker to establish the hydrodynamic size and the zeta potential. Run the scan to conclude the emission and absorption wavelength (Lambert et al., 2006). Another procedure of making silane-coated QDs leads to organic-soluble ones that are handled with ligand exchange before QDs become watersoluble. Comparable to the process above, the procedure begins with CdSe/ ZnS nanomaterials that are made according to the previously published process. The resulting quantum dot shell/core nanocrystals are condensed with the SiO2 shell utilizing the following procedure (Zhang et al., 2002): •

•

• • • •

Place 10 mL of cyclohexane, 1.3 mL of NM-5, 400 µL of CdSe/ ZnS stock solution in the chloroform, and 80 µL of TEOS (tetraethylorthosilicate) in the flask with energetic stirring. 30 mins after the system of the microemulsion is formed add 150 µL of ammonia aqueous solution to start the process of polymerization. Allow the procedure to develop silica over 24 hours with energetic stirring. Isolate the nanomaterials from the microemulsion by simply adding acetone trailed by centrifugation. Gather the precipitate comprising of CdSe/ZnS/SiO2 composite particle. Consecutively wash with 1-butanol (C₄H₁₀O), 1-propanol (C₃H₈O), ethanol (C2H5OH), and water to eliminate any surfactant and the unreacted molecules. Disperse the precipitate completely in every solvent to eliminate any physically adsorbed molecule on the surface of the particle.

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The consequential silica-encapsulated nanomaterials are resuspended in an anticipated solvent and considered for size, concentration, QY, and maximum wavelengths of absorption and emission. These CdSe/ZnS/ SiO2 are transformed into the water-soluble form utilizing ligand exchange (Gaponik et al., 2002).

2.2.4. Polymer Coating Polymer coating on several organic synthesized nanomaterials has been utilized to convert NMs into a water-soluble form. The polymer-covered nanocrystals have been utilized in biological studies. The hydrophobic nanocrystals are altered with the amphiphilic polymer shells making nanocrystals hydrophilic, therefore water-soluble. This is accomplished by the reaction of bis(6-aminohexyl) amine, amphiphilic polymer with the surfactant-protected molecules that outcomes in the cross-linking of chains of polymers around the nanomaterials that make them water-soluble. In one more process, phospholipid micelles and biomolecules have been covalently associated with semiconductor QDs for application in ultrasensitive biological detection (Sondi et al., 2000). PEG (Polyethylene glycol) is a polymer extensively utilized for several uses including encapsulation of nanomaterials (Figure 2.4) because of its low antigenicity and hydrophilicity. In addition to the steric stabilization of SPIONs (superparamagnetic iron oxide nanoparticles), PEG averts plasma opsonization along with uptake by macrophages, thus increasing the circulation time of SPION in vivo. PEG-covered SPIONs are proficiently internalized by cells through fluid-phase endocytosis and via amphiphilic attraction to lipid bilayers on the plasma membranes. These features, however, upsurge their capability to overload the cells with Fe (iron) and become poisonous (Wuister et al., 2003). PVA (Polyvinyl alcohol) is an organic polymer utilized as the coating for SPIONs. PVA has outstanding film-forming, adhesive, and emulsifying properties. The utilization of PVA for intravenous delivery is restricted because of poor persistence along with agglomeration in the ferrofluid. Conversely, when cross-linked to form the magnetic gel, PVA can be utilized as the vitreous eye substitute since it is a highly biocompatible material. Possibly, when utilized with SPIONs, biocompatibility can be used in tissue engineering (TE), targeted drug delivery, and biosensor technology (Nirmal et al., 1996).

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Figure 2.4: Transmission electron microscopy of PEG-encapsulated 30-nanometers diameter IOMNPs. Source: https://www.sciencedirect.com/topics/chemistry/poly-isobutylene.

Uyeda et al. (2005) studied the synthesis and design of ligands utilized with the biotin end group. The intended ligands had the central TEG (tetramethylene glycol) segment, lateral biotin, and the dithiol terminal group to attach to the surface of QD. Fastening biotin at the edge of quantum dot surface-attached ligands offered an avidin bond for the avidin-biotinbinding to attach proteins and the other biomolecules on the surface of the quantum dot. Exchange reactions were executed with varied ligands and the binding assays of the biotin-covered water-soluble quantum dot to NeutrAvidin-utilized substrates displayed specific capture via avidin-biotin interactions. Chitosan (CS), the polysaccharide comprising casually distributed β-(1-4)-associated D-glucosamine and N-acetyl-D-glucosamine provides a biocompatible, natural, cationic, and hydrophilic polymer covering that is appropriate for affinity refinement of proteins and the magnetic bioseparation (Banin et al., 1998). CS-covered SPIONs that were utilized to label fibroblasts enhanced their invasive capability under the magnetic force, displaying potential for TE (Sukhanova et al., 2004). Dextran, the polysaccharide, has been applied in covering nanomaterials. For biological uses, SPIONs are normally coated with organic biodegradable compounds like carbohydrate derivatives or dextran that are usually utilized

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as plasma expanders having a high affinity to oxides of iron. Various such formulations are commercially available now for human consumption like Ferridex, Combidex, Resovist, and AMI-288/ferumoxytol that are effectively used as MRI (magnetic resonance imaging) contrast agents (Nath and Chilkoti, 2002; Reiss et al., 2002). The biocompatible polymers having amphiphilic nature have been stated for coating nanoparticles to make them hydrophilic. The group of Hu stated the epoxidation of surface OA ligand and the further coupling with mPEGOH (polyethylene glycol monomethyl ether) to coat the nanophosphors surface. The efficient covering of the surface of nanophosphors with mPEGOH was validated by 1H NMR spectrometry, FTIR (Fourier-transform infrared) spectroscopy, and DLS (dynamic light scattering) studies, but PL and TEM spectroscopy displayed no clear variations in the luminescence and morphologies before and after the coating. The protocol given below was implemented by Hessel et al. (2010): •

Part 1: Synthesis of Amphiphilic Polymer – In the capped, round-bottom flask, pour 100 mL anhydrous THF (tetrahydrofuran), 15 mmol dodecyl amine, and poly(isobutylene-alt-maleic anhydride) sequentially to form the turbid white solution. – Sonicate the flask for one min to suspend the polymer which is not soluble. – Heat the given suspension to 60°C for 3 hours under energetic stirring. The suspension starts becoming clear after 15 minutes of stirring, signifying that the polymer has become soluble in THF after coupling covalently with the hydrophobic dodecyl amine molecules. – Cooldown this solution to room temperature. – Using the rotary evaporator, decrease the volume to 20 mL. – Stir this clear solution at 60°C for 12 hours to confirm the entire coupling between the dodecylamine and polymer. – Cooldown to room temperature and evaporate the residual solvent with the rotary evaporator that leaves behind the pale-yellow color, solid amphiphilic polymer. – Transfer this polymer to the glove box filled with nitrogen and dissolve in an anhydrous CHCl3 to give the monomer unit concentration of nearly 0.8 M.

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–

Store this amphiphilic polymer solution in the glass vial in a glove box until utilization. • Part 2: Coating the Silicon Nanocrystals with Polymer – In the 50 mL round bottom flask, properly mix the stock solution of amphiphilic polymer and alkyl-Silicon nanomaterials at 3 mg/ mL in an anhydrous CHCl3, 0.40 mL, and anhydrous CHCl3. – Swirl the mixture and then stir with the magnetic stirrer for almost 15 min at room temperature. – Eradicate the solvent with the rotary evaporation to produce the yellow film of silicon-polymer on the inner wall of the flask. – Add aqueous SBB (sodium borate buffer) and stir for almost 15 min at room temperature to disperse the siliconepolymer. – Add 13 mL DI water to dilute the nanomaterials. – Pass this suspension through the 0.2-µmeter pore syringe filter followed by the 0.1-µmeter pore syringe filter. – Filtered nanocrystal solution is then placed in the ultracentrifugation filter and centrifuged at 4000 g for nearly 4 min at room temperature. – Remove the colorless filtrate and preserve the concentrated nanomaterials solution above the membrane. – Dilute the nanomaterials solution with 15 mL sterile-filtered phosphate-buffered saline (PBS). – Repeat the process of ultracentrifugation 2 more times utilizing PBS to dilute the reserved nanomaterials solution. – Store the ultimate aqueous nanomaterials solution in the glass vial under surrounding conditions until utilization. – Illustrate the amphiphilic polymer-covered nanomaterials. Hessel and coworkers utilized XRD (X-ray diffraction), ATR-FTIR (attenuated total reflectance FTIR) spectra (400 to 4000 cm–1), and XPS (X-ray photoelectron spectroscopy) to illustrate the surface composition and also to validate that amphiphilic polymer effectively coated the nanomaterial’s surface. A PL, ultraviolet-Vis spectrophotometer and PLE (photoluminescence excitation) were utilized to conclude the optical

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properties. The zeta potential was measured with the help of laser Doppler anemometry utilizing the Zetasizer Nano ZS instrument. DLS and TEM are good non-destructive instruments to establish the physical characteristics of nanomaterials (Figure 2.5).

Figure 2.5: DLS and TEM of carboxyl-utilized PEGylated IOMNPs. Source: https://www.sciencedirect.com/topics/pharmacology-toxicology-andpharmaceutical-science/dodecylamine.

2.3. NM BIOCONJUGATION To be helpful in various specific medical uses, the hydrophilic water-soluble nanomaterials must be functionalized to load the interesting biomolecules. Water-soluble functionalized nanomaterials have the essential bioreceptors to execute the action that it is meant for. The bioreceptors comprise proteins, lipids, DNA, carbohydrates, or whole or parts of microorganisms. Several nanomaterials like QDs, CNTs, metal oxides, metal nanoparticles (silver,

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silica, and gold), and polymer and semiconductor nanowires fixed to the bioreceptors make them helpful for several medical uses (Snee et al., 2006). The nanomaterials are functionalized with the biocompatible materials to permit specific and selective interactions with the biomolecules that are exclusive to each nanomaterial application. Functionalization of the nanomaterials is also critical to simplify self-assembly and nanopatterning on solid surfaces. Biocompatible-utilized nanomaterials may be utilized for medical diagnostics, multiple or single drug delivery, imaging, and theranostics (Talapin and Murray, 2005). Novel developments comprised water-based synthesis techniques for nanomaterials that produce particles emitting from visible to the NIR (nearinfrared) spectrum. The particles are fundamentally water-soluble and are helpful in biological environments. The surface-altered nanomaterials need biological interfacing to be helpful for particular applications.

2.3.1. NM Bioconjugation Methods The surface-functionalized nanomaterials are conjugated to the biomolecules, making them helpful for various medical and biological applications. Conjugation can normally be done using traditional conjugation methods dependent on the NM’s surface functional group and also on the biomolecule. The conjugation to nanomaterials may be done via ligand-like addition by chemisorption to the core of nanomaterials as in the situation of sulfurcomprising groups, hydrophobic interactions (HI), electrostatic adsorption, conjugations via covalent binding of the groups on the surface modifier and particle, or through the receptor-ligand interface as in the situation of the avidin-biotin system (Aldana et al., 2005; Talapin and Murray, 2005). PEGs and Thioctic acid have been utilized in simple esterification approaches, trailed by the reduction of 1,2-dithiolane to make the series of DHLA-PEG (PEG-terminated dihydrolipoic acid) as the substrates for capping. Cap exchange reaction of TOPO/TOP-capped QDs with these substrates developed water-soluble nanocrystals that are steady over prolonged periods. The nanocrystals were stable over the wide range of pH, from slightly acidic to the basic conditions but these ligands did not have particular functional end groups for simple implementation of conjugation methods, like avidin-biotin binding. Additional studies were stated on the synthesis and design of ligands utilized with the biotin end group. The intended ligands had the central TEG (tetraethylene glycol) segment, lateral biotin, and the dithiol terminal group in order to attach to the surface of QD.

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Fastening biotin at the edge of quantum dot surface-attached ligands offered an avidin bond for the avidin-biotin-binding in order to attach proteins and the other biomolecules on the surface of a quantum dot. Exchange reactions were executed with varied ligands and the binding assays of the biotincovered water-soluble quantum dot to NeutrAvidin-utilized substrates displayed specific capture via avidin-biotin interactions (Delehanty et al., 2006). Nanoscale dimensions of the nanomaterials bring electronic, optical, catalytic, magnetic, and some other properties that are different from those of molecules/atoms or bulk materials. To exploit the exceptional properties that arise because of the nanoscale dimensions of nanomaterials, researchers must govern and control the shape, size, and surface functional groups and also structure them into intermittently ordered assemblies to create novel devices, products, and technologies or enhance the prevailing ones. The art of manipulating/controlling the properties and using these nanomaterials for the objective of making microscopic machinery can normally be done utilizing the “bottom-up” or “top-down” approach. In the top-down strategy, large chunks of the materials are shattered down into nanostructures with the help of lithography or any external force that executes the order on nanomaterials. The bottom-up strategy follows nature’s lead in forming amazing materials and molecular machines by making nanostructures from molecules or atoms or any steady building blocks via the understanding and utilization of ordertempting factors that are intrinsic in a system (Zhang et al., 1996). The mechanism of fabrication/formation of new nanostructures from the selfassembly of proteins, lipids, and peptides has been clarified as described in the review article by Zhang et al. (1996) giving a brief understanding of factors that control the growth and order of the nanomaterials that has led to the number of new structures and functionalities. The nanostructures comprise nanofibers, amphiphilic protein scaffolds, bionanotubes, and nanowires that have possible uses in the biomedical field, electronic industry, and computer information technology (Duan and Nie, 2007). The application of nanomaterials in medicine is quickly acquiring ground in the area of medical diagnostics. Driskell and Tripp (2009) discoursed the different approaches for diverse illness diagnostics and how nanotechnology can modernize these approaches. Lee et al. (2008) reviewed current advances in microfluidic/nanotechnologies for clinical POC (pointof-care) applications in resource-restricted settings in developing countries. Researchers have defined the utilization of nanomaterials as barcodes or labels in conjunction with the microfluidic systems for automatic sample

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preparation and the sample assays for infective disease diagnostics (Gao et al., 2004). One of the uses of nanomaterials that rely almost entirely on the utilization of the nanomaterial is a biosensor. The biosensor is made up of the biorecognition element that interrelates with the molecules and the transducer and observes the interaction and transforms the binding event to the measurable analytical signal. The biosensors are categorized according to the bioreceptor utilized or biological procedure involved like immunologic (Ab-antigen-based) DNA (nucleic acid-based) or biocatalytic (enzyme-based) sensors. Biosensors that utilize nanomaterials are known as nanosensors. Nanosensors are made in several new ways utilizing the improvement of performance through several properties of the nanomaterials employed. Current advances in synthetic chemistry and materials science have made it feasible to yield high-quality nanomaterials in the shape of nanoparticles (nanorods, nanotubes, nanospheres, nanoarrays, and nanowires) that have been utilized for the growth of biosensors due to their substantial benefits over bulk and microscale materials that comprise (1) size-tunable properties, (2) large surface to volume ratio, (3) shape-dependent properties, (4) lower energy ingestion, (5) miniaturized biosensors, and (6) cheap (Bruchez et al., 1998).

2.3.2. Covalent Conjugation of the Biomolecules to Nanoparticles Covalent attachment of the biorecognition moiety to the utilized nanomaterial is amongst the more broadly utilized approaches for converting the nanomaterial for a particular application. For instance, tumor cells that are flowing in the blood can normally be labeled and diagnosed utilizing this method. Xu et al. (2011) displayed particular targeting of the breast cancer cell lines SK-BR3 utilizing QDs that were utilized with Abs against the human endothelial receptors forming QD-Ab. HER2 is the surface covering protein that is generally overexpressed in breast cancer cells. The breast cancer cells (SK-BR3) that were uncovered to QD-Ab, seemed fluorescent under the UV illuminated microscope (Figure 2.6) making the cells imaging under the microscope quite easier. Moreover, cells that are explicitly stained with the biomolecule-functionalized QDs offer benefits compared to those that are stained with the organic dyes because QDs are resilient to photobleaching, have very high brightness and are steady in cells for nearly 6 months at ambient room temperature.

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Figure 2.6: Digital image of SK-BR3 breast cancer cells exposed to the QDanti-EpCAM. The quantum dots had a diameter of ~8 nanometers emitting at 620 nanometers. Source: https://www.semanticscholar.org/paper/Development-of-semiconductor-nanomaterial-whole-on-Xu-Aguilar/f13978ab25b6b19e831c02da019cb56 04dec18ff?p2df.

Nanomaterial bioconjugation via covalent binding is favored to avert the desorption of biomolecules from the NMs surface (Dubertret et al., 2002). Bioconjugation of nanomaterials with carboxyl functional group on the surface frequently utilizes the derivative of carbodiimide 1-ethyl3-(3-dimethyl aminopropyl) carbodiimide for associating to the amine group on the biomolecules (Kukur et al., 2003; Yang and Gao, 2005). Nanomaterials functionalized with sulfhydryl groups are triggered with a linker 4-(N-maleimidomethyl)-cyclohexane carboxylic acid N-hydroxysuccinimide ester for associating with the amine group of the biomolecule (Dubertret et al., 2002). One instance of carbodiimide chemistry in infectious illness diagnostics is the conjugation of pathogen biomarkers HBsAg (hepatitis B surface antigen), HCV NSP4 (nonstructural protein 4), and HIV gp41 (glycoprotein 41) to the surface of QDs barcodes. The utilization of QDs barcodes as well as advances in photon detection and microfluidic technologies, proteomic biomarkers of the infection, and signal processing, have shown the capability to be established as the handheld device for point-of-center diagnostics. Researchers have displayed how carbodiimide chemistry was utilized to conjugate the oligonucleotides (ONTs) to red and green nanoparticles

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probes for intact RSV (respiratory syncytial virus) and that the utilization of bioconjugation of 2-color nanoparticles to recognize simultaneously two binding sites in the single target permit for recognition of intact viruses lacking the necessity for target intensification or the necessity to isolate probe from the target molecules (Kukur et al., 2003; Yang and Gao, 2005). Similar carbodiimide chemistry was utilized to conjugate Abs against EpCAM (epithelial cell adhesion molecules) to identify breast cancer cells via QD-based particular imaging (Figure 2.7). The cancer cells of the breast under the white light were difficult to notice under the microscope as compared to when the cancer cells were stained explicitly with the Abconjugated QDs. Moreover, the QD-Ab-stained cancer cells of the breast stayed fluorescent even after 6 months of storing at room temperature (Zhu et al., 2007).

Figure 2.7: Image of SK-BR3 breast cancer cells stained with green color emitting quantum dots emitting at 530 nanometers fixed to Ab against the cell membrane proteins. The quantum dots-Ab are observed as dots along the membrane of the cell to bring visible color to the cells. Source: https://link.springer.com/book/10.1007%2F978-981-15-5062-1.

Carbodiimide chemistry utilizing 1-ethyl-3-3(3-dimethyl aminopropyl) carbodiimide hydrochloride as the cross-linker has generally been utilized to functionalize the tris(2,2′-bipyridyl) dichlororuthenium(II) hexahydrate (RuBpy)-doped silica nanoparticles for the consequent restriction of Ab for the Escherichia coli. The Ab-bioconjugated nanoparticles permitted for quick and precise detection of a single bacterium lacking the necessity for enrichment or amplification.

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Another bioconjugation approach utilizes the homobifunctional coupler, PDITC (1,4-phenylenediisothiocyanate), to fix the 38-kDa tuberculosis (TB) antigen to the amino group of APTS (aminopropyltriethoxysilane)-the altered surface of the sensor and the amino groups of antigens. The coupling chemistry permitted for particular binding but inhibited nonspecific binding of the blood serum and entire blood compounds in the serodiagnostic measurement of TB infection using three optical sensing platforms (Darbandi et al., 2005). Common conjugation methods like SMCC or carbodiimide chemistries are normally used in nanomaterials. However, Mattousi’s group discussed against the EDC conjugation of QDs for a few reasons: the creation of aggregates because of instability of QDs and the several feasible crosslinking reactions that triggered the creation of an uncontrolled and large number of conjugates on the single nanocrystal (Alivisatos, 1992; Willard et al., 2001). However, EDC chemistry is broadly utilized for the creation of commercial quantum dot-avidin/ streptavidin conjugates having high QY, which is utilized to fix different functionalities on QDs to permit for a more particular interaction with diverse target analytes. To solve the concerns of Mattousi, Ocean NanoTech developed a quantum dot-coupling kit that comprises all the buffers and reagents necessary to avert aggregation and preserve colloidal stability whereas governing the number of biomolecules on NM’s surface (Sun and Rollins, 1998). The procedure includes the activation of carboxylated nanoparticles with EDC/NHS trailed by the addition of a biomolecule. The efficiency of conjugation is tested via gel electrophoresis or via a suitable biomolecule assay. Applications of nanomaterials like QD tagging of the particular target biomolecule or the cell or a microorganism comprise grafting the recognition receptor to utilize quantum dot surface. Researchers have utilized semiconductor QDs made from CdSe/ZnS shell/core QDs, as the solid surfaces on which the nucleic acid comprising the ribonucleic acid primer was mobilized (Wisher et al., 2006). The QDs display photochemical centers to light up the diminuendos of telomerization, which takes place on the nanoparticles by FRET (fluorescence resonance energy transfer). The attachment of the nucleic acid unit, comprising the G-rich sequence acknowledged by telomerase for generation of the telomerase activity, confined the thiolated end group, due to which it became feasible for the attachment to CdSe/ZnS QDs. In the existence of telomerase from the HeLa cancer cells and the mixture comprising dNTP and the Texas-Red 14-dUTP, a peak of emission at the wavelength equal to 560 nanometers was perceived

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(Fahmi et al., 2003). Emission of light reduces with time, as the emitted light is passed on and then absorbed by a dye-altered dUTP, in the existence of telomerase activity, displaying absorbance at the wavelength equal to 610 nanometers. Functionalized quantum dots and other nanomaterials contain either a carboxyl group or the amine group that gives the probability of covalent bonding or cross-linking molecules comprising the thiol group, hydroxyl group, carboxyl group, or the N-hydroxysuccinimydyl ester moiety with help of the standard bioconjugation reactions. Another strategy for nanomaterial functionalization utilizes electrostatic interactions amongst nanomaterials and the adapter biomolecules, or amongst NMs and DNA, proteins, etc. These steps of functionalization can be reiterated to add two or more operational moieties or to vary functionality. One instance is QDstrep (streptavidin-coated QDs) utilized in combination with the biotinylated Abs or proteins creating QDstrep-biotinAb. The structure, QDstrep-biotinAb, dependent on the specificity of Ab, can be utilized for (1) a particular entire cell or the tissue staining, or (2) particular medical sensing.

2.3.2.1. Procedure for Covalent Conjugation of Nanoparticles to Quantum Dots (QDs) The biomolecule conjugation procedure can be utilized for water-soluble nanomaterials that comprise carboxyl groups on the surface (Xu et al., 2007). The procedure is given below: • • • •

• • • • •

Place 50 µL of 4 µM quantum dot aqueous solution in the low protein tie 1.5 mL centrifuge tube. Add 300 µL of quantum dot reaction buffer to the QDs and mix well. Add 50 µL of EDC solution. Add at least five nmol of protein to make the 1 nmol quantum dot to 5 nmol protein. The ratio can be decreased or increased as necessary. Mix well and then react for 2 hours in the vortex mixer. Add 10 µL of the quenching buffer and permit it to react for nearly 10 to 15 min at room temperature. Spin filter, dialyze, or utilize ultracentrifugation to purify. Resuspend in the storage buffer. Refrigerate until utilization.

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To keep the action of proteins and to avert pollution, only utilize autoclaved buffers during the process of conjugation. It is great to carry out conjugation in aseptic conditions.

2.3.2.2. Particular Staining of the Cancer Cells with Quantum Dots (QDs) Fixed to Ab Against the Cell Membrane Surface Proteins The following procedure can generally be applied to particular attachments of nanomaterials that are conjugated covalently with Ab on the membrane of a cell (Skaff et al., 2004): • • •

Insert the coverslip in every well of the six-well culture plate; Place 5000 cells in every well and add one mL culture media; Nurture the cells under the recommended conditions of the manufacturer; • When the growth is about 70–80% confluence, eradicate the growth medium; • Add 500 µL of 1× DPBS (Dulbecco phosphate-buffered saline); • Add 10 µL of 1 to 50 nM quantum dots-Ab and aspirate moderately to mix; • Incubate at 37°C with 5% CO2 in the incubator oven for about 3 to 10 min; • Wash three times with 1× DPBS having 0.02% Tween 20 and 1% BSA to eradicate additional QDs-Ab; • Observe under the fluorescence microscope. The SK-BR3 breast cancer cells in Figure 2.7 under the fluorescent microscope display the QDs-Ab as dots. This is a result of QDs-Ab targeting and fixing particular proteins on the cell membrane’s surface. Particular targeting with nanomaterials fixed to Abs is a beneficial application of nanomaterials for sensor development along with targeted delivery of the drug (Gupta and Curtis, 2004).

2.3.3. Electrostatic Charge-Charge Interaction Other approaches that have been utilized in the biosensors for infectious illness diagnostic devices comprise electrostatic interactions. For instance, silver nanoparticles (AgNP) in polyacrylic acid/ polystyrene sulfonate capsules were covered with avidin through electrostatic interactions

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and utilized as a tag for the electrochemical recognition of E. coli DNA hybridization via the biotin-avidin interaction (Maruoka et al., 2006). Their utilization of capsules of AgNPs (silver NPs) was stated to (a) lower the limit of detection than the other AgNPs-centered assays; (b) lower the limit of detection in comparison to several hybridization assays utilizing other nanomaterials; and (c) reach the chemiluminescence sensitivity, which is stated to be amongst the most sensitive deoxyribonucleic acid (DNA) detection methods utilizing AgNPs. Meyer’s group has utilized the particular biotin-avidin interface when they utilized commercially made magnetic beads covered with streptavidin for the detection of Francisella tularensis and Yersinia pestis (Niemeyer, 2001). The principle of detection utilized anti-YPFI or anti-Ft Abs for catching the YPFI or Ft antigen. The biotinylated antigens were coupled with streptavidin in the magnetic beads. Binding occasioned the variation in an induced magnetic field. The streptavidin-modified magnetic beads exhibited potential in the growth of fast, easy, and very sensitive biosensors for the recognition and quantification of diseases mentioned.

2.4. APPLICATIONS OF BIOCOMPATIBLE NANOMATERIALS Biomedical uses of nanomaterials in the area of medicine and life sciences research generally are growing quickly. Nanomedicine not only aims to develop a beneficial set of research devices and tools, but also gathers a lot of consideration for its probable commercial uses in the field of the pharmaceutical industry that might comprise targeted drug delivery systems, novel therapies, and the in vivo imaging. (Coombs,1996)Nanomaterialcentered neuro-electronic interfaces, NMs-based strip immunoassays, nanobiosensors, and nanoelectronic-centered sensors are amongst the active and ongoing areas of research in the field of nanotechnology. Going down to the level of molecules, nanotechnology holds the potential that cell healing can be executed by the molecular nanomachines that might revolutionize the medical field and medicine. Nanomedicine sales reached around 6.8 billion $ in 2004 with around 38 products and 200 companies all over the world putting the minimum of nearly 3.8 billion $ in nanotechnology research and development investment each year. This extraordinary rate of growth in nanomedicine is anticipated to have a substantial impact that can enhance the worldwide economy.

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Although techniques for bioconjugation of nanomaterials have existed for a while, it is evident that their use in infectious disease diagnostics is limited.. Currently, bioconjugation of nanomaterials is done to make them the probes for imaging, as the vehicles for delivery of cancer drugs, and as the therapeutics for the elimination of the tumor cells. Nanomaterials are presently being comprehended for drug delivery systems (DDSs) to enhance the bioavailability of the drug, where they are needed most in the body over the frame of time, which will be accomplished by molecular targeting utilizing nano-engineered devices. Nanomaterials have rare properties that can be utilized to enhance drug delivery. Attachment of particular probes that assist the nanomaterials to the particular cell as a particular tissue can save around 65 billion dollars that are wasted every year because of poor bioavailability. The systems of drug delivery utilizing lipid- or polymercentered nanomaterials or magnetic nanoparticles can be made to enhance the therapeutic and pharmacological properties of usually non-potent and probably harmful drugs to adjacent healthy cells. Drugs composed of peptides and proteins exhibit huge potential for the treatment of several disorders and diseases. Targeted and controlled delivery of biopharmaceuticals utilizing nanomaterials is a quickly growing field of research (Figure 2.8) (Susumu et al., 2007).

Figure 2.8: Applications of biocompatible NMs.

Source: https://www.sciencedirect.com/science/article/abs/pii/ S0168365912008553.

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Nanomaterials are actively being made for in vivo and in vitro imaging. Magnetic nanoparticles are being utilized as contrast agents providing enhanced images from MRI and ultrasound. Diagnosis of diseases like infectious diseases and cancer at their initial stages for efficient treatment might be accomplished with more stable, brighter, and more sensitive nanomaterials (Sasaki et al., 2008). QDs having quantum confinement properties such as size-tunable emission of light when utilized in conjunction with MRI can yield exceptional images of the tumor sites. These nanoparticles are brighter as compared to the organic dyes and just require one source of light for excitation. This gives the meaning that the utilization of fluorescent QDs could yield a higher contrast picture and at a lower cost as compared to organic dyes available today that are utilized as contrast agents. The small size of nanoparticles (10–100 nm) permits them to preferentially gather at the sites of a tumor, which does not have an efficient lymphatic drainage system (Wilhelm et al., 2003). Biosensor development is amongst the quickest growing fields of nanomaterial applications in medicine. The sensors might be in the shape of glass slide-kind, lateral flow immunoassay sensors, or disposable lab on the chip-kind of sensors. An approach utilizing the solid phase comprising the sandwich-kind assay with the Ab against a particular target and the QD-labeled Ab permits QD-centered recognition of the interested analyte. A large number of promise surface attachment groups on QDs permits the possible integration of several molecules for sensing (Figure 2.9) (McCarthy et al., 2007).

Figure 2.9: Applications of carbon nanomaterials in manufacturing of biosensors. Source: https://www.researchgate.net/figure/The-role-of-carbon-nanomaterials-in-the-development-of-biosensors_fig1_335211672.

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In a study, Xu and coworkers (2007) demonstrated the utilization of IOMNPs for immunomagnetic separation of the tumor cells from whole blood. The procedure involved 30 nanometers IOMNPs that are normally amphiphilic polymer-coated. The IOMNPs were conjugated covalently with Abs against the human epithelial factor of growth receptor 2 (anti-HER2/ neu or anti-HER2) creating IO-Ab. HER2 is the cell membrane protein overexpressed in various kinds of human cancerous cells. Using the HER2/ neu overexpressing SK-BR3 cell as an example cell, the IO-Ab effectively separated about 73.6% of SK-BR3 cancer cells that were jagged in one mL of human whole blood (Xu et al., 2011). The IO-Ab is specially bound to SKBR3 cancer cells over the 1 × 109 normal cells discovered in blood because of the higher level of HER2/neu receptor on the cancer cell membrane’s surface different from the surface of the normal cell membrane. Their studies displayed an enrichment factor of 1:10,000,000 in the magnetic field through the tie of IO-Ab on the surface of a cell that occasioned the special capture of cancer cells. Additionally, as displayed in the instances above, various studies on bioconjugated nanomaterials for infectious illnesses diagnostics have begun to emerge. The studies have displayed that the utilization of nanomaterials as conjugates to the biorecognition elements has potential in the growth of biosensing devices. These devices are fast, easy to use, highly sensitive, and skilled in identifying analytes even in complex media such as blood. Furthermore, because of the NMs’ small dimensions, they can be integrated into manageable handheld devices for point-of-center diagnostics (Figure 2.10) (Hessel et al., 2010).

Figure 2.10: Applications of nanomaterials in detection and treatment of cancer. Source: https://www.researchgate.net/figure/Nanomaterial-Based-Therapeutics-A-Application-of-nanomaterials-in-cancer-therapy-B_fig1_317096605.

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Bioconjugation of nanomaterials for diagnostic uses has triggered more selective and more particular sensing of the target analytes. Nevertheless, for the growth of cheap sensing devices that permit complex sensing and simultaneously, provide high-resolution and fast analysis, the surface of the transducer is frequently nanomanipulated. Nanomanipulation method includes EBL (electron beam lithography), OAD (oblique angle deposition), NIL (nanoimprint lithography), NSL (nanosphere lithography), µCP (microcontact printing), dip-pen lithography, and several self-assembly methods. This section presents only sensor fabrication of the most auspicious sensors in the area of a point of center medical diagnostics—FET (field effect transistor)-centered potentiometric sensors and LSPR (localized surface plasmon resonance), and SERS (surface-enhanced Raman spectroscopy). In applications where reproducibility and uniformity of the surface property are vital, the costly top-down methods such as EBL are the approach of choice. This is because of the point that bottom-up methods such as NSL and NIL suffer from reliability and reproducibility issues. However, bottomup approaches are gaining significance owing to the simplicity, low cost, and speed of the techniques (Hessel et al., 2010). One of the auspicious applications of biocompatible nanomaterials is drug delivery. Today, various nano-enabled drugs are accessible for several applications. Apart from the utilization of nanomaterials for drug encapsulation and MRI contrast agents, some are being studied for the delivery of the vaccine. In this study, the researchers concentrated on the utilization of semiconductor nanomaterials, particularly the QDs as a substitute platform for vaccine delivery. They utilized