Toxicology of Nanoparticles: Insights from Drosophila [1st ed.] 9789811555213, 9789811555220

Table of contents :
Front Matter ....Pages i-xii
Synthesis and Characterization of Nanoparticles Used in Consumer Products (Akanksha Singh, Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 1-27
Model Organisms for In Vivo Assessment of Nanoparticles (Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 29-57
Impact of Nanoparticles on Behavior and Physiology of Drosophila melanogaster (Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 59-67
Dose-Dependent Influence of Nanoparticles on Fertility and Survival (Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 69-78
Effect of Nanoparticles on Maintenance of Metabolic Homeostasis (Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 79-87
Nanoparticles: An Activator of Oxidative Stress (Akanksha Singh, Akanksha Raj, Prasanna Shah, Namita Agrawal)....Pages 89-106
Safe Dose of Nanoparticles: A Boon for Consumer Goods and Biomedical Application (Akanksha Raj, Akanksha Singh, Prasanna Shah, Namita Agrawal)....Pages 107-122

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Namita Agrawal Prasanna Shah   Editors

Toxicology of Nanoparticles: Insights from Drosophila

Toxicology of Nanoparticles: Insights from Drosophila

Namita Agrawal  •  Prasanna Shah Editors

Toxicology of Nanoparticles: Insights from Drosophila

Editors Namita Agrawal Department of Zoology University of Delhi Delhi, India

Prasanna Shah Department of Physics Acropolis Institute of Technology and Research Indore, India

ISBN 978-981-15-5521-3    ISBN 978-981-15-5522-0 (eBook) https://doi.org/10.1007/978-981-15-5522-0 © Springer Nature Singapore Pte Ltd. 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Contents

1 Synthesis and Characterization of Nanoparticles Used in Consumer Products������������������������������������������������������������������������������������������������������   1 Akanksha Singh, Akanksha Raj, Prasanna Shah, and Namita Agrawal 2 Model Organisms for In Vivo Assessment of Nanoparticles������������������  29 Akanksha Raj, Prasanna Shah, and Namita Agrawal 3 Impact of Nanoparticles on Behavior and Physiology of Drosophila melanogaster ����������������������������������������������������������������������������������������������  59 Akanksha Raj, Prasanna Shah, and Namita Agrawal 4 Dose-Dependent Influence of Nanoparticles on Fertility and Survival��������������������������������������������������������������������������������  69 Akanksha Raj, Prasanna Shah, and Namita Agrawal 5 Effect of Nanoparticles on Maintenance of Metabolic Homeostasis������������������������������������������������������������������������������������������������  79 Akanksha Raj, Prasanna Shah, and Namita Agrawal 6 Nanoparticles: An Activator of Oxidative Stress������������������������������������  89 Akanksha Singh, Akanksha Raj, Prasanna Shah, and Namita Agrawal 7 Safe Dose of Nanoparticles: A Boon for Consumer Goods and Biomedical Application���������������������������������������������������������������������� 107 Akanksha Raj, Akanksha Singh, Prasanna Shah, and Namita Agrawal

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About the Editors

Namita Agrawal  is a Professor at the Department of Zoology, University of Delhi, India. Prior to joining the University of Delhi, she worked as a post-doctoral fellow, followed by research scientist and research specialist positions at the Department of Developmental and Cell Biology, University of California, Irvine, USA. She also served at the University of California, Irvine as a visiting scientist (2009–2012). She has 12 years of experience in teaching Genetics, Cytogenetics and Developmental Biology to post-graduate students at the University of Delhi. Her research is focused on various diseases like cancer, neurodegenerative diseases in consort with nanotoxicity using Drosophila as a model organism. She has published numerous research articles in peer-reviewed journals like Science, PNAS, Journal of Cell Biology, Development, Developmental Biology, Nature Scientific Reports, and PLOS One, etc. She is also a member of various international societies. Prasanna Shah  worked as a post-doctoral fellow in USA with Indiana University Purdue University, University of Texas at Dallas and West Virginia University (2000–2012). Prior to which she was a STA fellow in Japan (1998–2000). She is a recipient of the Indian Science Congress Young Scientists Award (1995) and MPCST Young Scientists Award (1991). Her research interest comprises the study of nanoparticles for biomedical applications. She has extensive experience in the design, fabrication, and installation of inert-gas condensation chambers, which are used for nanoparticle synthesis. She has published many research papers in various peer-reviewed journals. She was Head of the Physics Department at Acropolis Institute of Technology and Research, Indore, India. vii

Abbreviations

ACC Acetyl-CoA carboxylase ADMET Absorption, distribution, metabolism, excretion and toxicity AFM Atomic force microscope AgGA AgNP with surface coatings-gum arabic AgNO3 Silver nitrate AgNPs Silver nanoparticles AgPEG AgNP with surface coatings-polyethylene glycol AgPVP AgNP with surface coatings-polyvinylpyrrolidone Akt/ASK1 Protein kinase B/apoptosis signal-regulating kinase 1 Aluminium nanoparticles Al2O3 NPs AMPK Adenosine monophosphate-activated protein kinase aSNPs Amorphous silica nanoparticles ATP Adenosine triphosphate AuNPs Gold nanoparticles BBB Blood–brain barrier BDNF Brain-derived neurotrophic factor BrdU 5-bromo-2″-deoxyuridine C60 Fullerene CAFÉ CApillary FEeder CB Carbon black CBMN Cytokinesis-block micronucleus CCD Charged-coupled device Cerium oxide CeO2 ChNP Chitosan nanoparticle CNFs Carbon nanofibers CNS Central nervous system CNTs Carbon nanotubes CoNPs Cobalt nanoparticles COPD Chronic obstructive pulmonary disease CR Caloric restriction CT Computed tomography CuNP Copper nanoparticle CuONP Copper oxide nanoparticle ix

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CuSO4 Copper sulphate CVD Chemical vapour deposition DC Direct current DCF Dichlorofluorescein DCFDA 2′, 7′-dichlorofluorescein diacetate DLS Dynamic light scattering DMSO Dimethyl sulfoxide EELS Electron energy loss spectroscopy ER Endoplasmic reticulum ETC Electron transfer chain EXAFS Extended X-ray absorption fine structure FAS Fatty acid synthase FCC Face-centered cubic fCNTs Functionalized carbon nanotubes FDA Food and drug administration Iron oxide Fe3O4 FoxO Fork head box O FWHM Full width at half maximum GI Gastro-intestinal GPa Giga pascal GSH Glutathione Hydrogen peroxide H2O2 HD Huntington’s disease HEBM High energy ball milling HEK293 Human embryonic kidney cell line HIF Hypoxia-inducible factor HRTEM High-resolution transmission electron microscopy HUVECs Human umbilical vein endothelial cells IL-6 Interleukin-6 IL-8 Interleukin-8 Inr Insulin receptor IR Infrared IR Insulin receptor IRS Insulin receptor substrate LaSiS Laser ablation synthesis in solution LDH Lactic acid dehydrogenase LDL Low-density lipoprotein MAPK Mitogen-activated protein kinase MCM-41  Mobil Composition of Matter No. 41 MDA Malondialdehyde MDR Multidrug resistance mES Mouse embryonic stem cells MEF Mouse embryonic fibroblasts MN  Micronuclei MNPs Magnetic nanoparticles

Abbreviations

Abbreviations

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MnSOD Mn-superoxide dismutase MPO Myeloperoxidases MRI Magnetic resonance imaging MTA Microculture tetrazolium assays MTS 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)2-(4-­sulfophenyl)-2H-tetrazolium MTT 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide mtTFA Mitochondrial transcription factor A MWCNTs Multi-walled carbon nanotubes NADPH Nicotinamide adenine dinucleotide phosphate NiONP Nickel oxide nanoparticle nfCNTs Non-functionalized CNTs NFκB Nuclear factor kappa-light-chain-enhancer of activated B cells NIR Near-infrared Nitric oxide NO. NOS Nitric oxide synthase NOX Nicotinamide adenine dinucleotide phosphate oxidase NPs Nanoparticles NSOM Near-field scanning optical microscopy Molecular oxygen O 2 1 O2 Singlet oxygen Superoxide O2. − OH− Hydroxyl ion ONOO− Peroxynitrite PAC Perturbed angular correlation PD Parkinson’s disease PBL Peripheral blood lymphocytes PDs Polymer dots PGC-1alpha Peroxisome proliferator-activated receptor-gamma coactivator-1alpha PI3K Phosphoinositide 3-kinase PMT  Photomultiplier tube PTPs Phosphotyrosine phosphatases PZT  Piezoelectric tube QDs Quantum dots ROS Reactive oxygen species RNS Reactive nitrogen species SDR Spinning disc reactor SEM Scanning electron microscope SiNPs Silica nanoparticles Silicon dioxide SiO2 SMART Somatic mutation and recombination test SOCE Store-operated calcium entry SOD Superoxide dismutase SPIO Superparamagnetic iron oxide SPR Surface plasmon resonance

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Abbreviations

SQUID Superconducting quantum interference device STEM Scanning transmission electron microscope SWCNTs Single-walled carbon nanotubes TAG Triacylglycerol TBARS Thiobarbituric acid reactive substances TEM Transmission electron microscope TGF-β Transforming growth factor-beta Titanium dioxide TiO2 TNF-α Tumor necrosis factor-alpha TNT Titania nanotube Regulatory T cell Treg TUNEL Terminal deoxynucleotidyl transferase deoxy uridine triphosphate nick end labeling UHV Ultra-high vacuum UV Ultraviolet UV-vis Ultraviolet-visible spectroscopy VSM Vibrating sample magnetometer WST-1 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2Htetrazolium, monosodium salt XANES X-ray absorption near-edge structure XPS X-ray photoelectron spectroscopy XRD X-ray diffraction XTT 2,3-Bis(2-methoxy-4-nitro-5-sulphophenyl)-5-carboxanilide-2Htetrazolium, monosodium salt ZnO Zinc oxide ZnONP Zinc oxide nanoparticle

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Synthesis and Characterization of Nanoparticles Used in Consumer Products Akanksha Singh, Akanksha Raj, Prasanna Shah, and Namita Agrawal

Abstract

Nanotechnology has revolutionized the consumer market globally due to its inimitable and far-fetched characteristic properties. Every synthesis technique has its pros and cons and therefore, according to the need, nanoparticles (NPs) are synthesized by various widely standardized techniques. After the synthesis of nanoparticles, evaluation of their physico-chemical properties is extremely important for determining their behaviour, bio-distribution, safety and efficacy. In particular, impact of nanoparticles on a biological system is one of the major concerns that has not been addressed adequately till date and it solely depends on their size, stability, surface property, etc. Metal nanoparticles are reported to have significant potential for numerous applications in the area of biomedical application, energy and information technology, optoelectronic and magnetic imaging that primarily depends on their size, shape and composition. This chapter deals with the major adopted techniques for the synthesis of nanoparticles and their physico-chemical characterization which is the foundation for achieving optimum benefits of nanoparticles in consumer goods and biomedical application. Keywords

Nanoparticles · Synthesis · Physico-chemical characterization

A. Singh · A. Raj · N. Agrawal (*) Department of Zoology, University of Delhi, Delhi, India P. Shah Department of Physics, Acropolis Institute of Technology and Research, Indore, India © Springer Nature Singapore Pte Ltd. 2020 N. Agrawal, P. Shah (eds.), Toxicology of Nanoparticles: Insights from Drosophila, https://doi.org/10.1007/978-981-15-5522-0_1

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Introduction

The field of nanotechnology has grown exponentially firstly due to the feasibility with which precise synthesis of nanomaterials is now possible and secondly due to miraculous properties they harbour for the betterment of mankind. Consumer products incorporating nanomaterials, e.g. healthcare and fitness products, clothing, food, cosmetics, and automotive and electronic appliances are increasing and have become an essential part of day-to-day life (Coelho et al. 2012; Kumar et al. 2015; Mu and Sprando 2010; Yetisen et al. 2016). Additionally, due to enormous potential of the nanoparticles, they are being utilized in biomedical applications for targeted drug delivery, bioimaging, regenerative medicine, immuno therapy etc. (Matteucci et al. 2018). Despite extraordinary advantages and advances in the improvement of consumer products and biomedical applications, a detailed understanding of their impact on human health is of major concern that needs further investigation. The genuine requirement is to harness their unique and exclusive physico-chemical properties by controlling various parameters. Once addressed in a systematic matter, optimum benefits of these relatively new materials can be cherished. Nanoparticles (NPs) are classified into various classes mainly depending on their unique physical and chemical properties. Their high surface area-to-volume ratio creates the uniqueness. Their optical properties are size dependent; they impart different colours due to absorption in the visible region. Many other properties of the nanoparticles are size, shape and structure dependent, for example reactivity and toughness, due to which they find such varied applications. Nanoparticles can be incidental or specifically synthesized. Incidental nanoparticles are produced unintentionally as a by-product made out of different elements with huge size and shape variation in the range of 1–100 nm whereas specifically synthesized nanoparticles are engineered, specifically designed and synthesized for a purpose. A common example differentiating incidental and engineered nanoparticles is carbon. Soot mainly comprises nanoparticles of carbon, found in the atmosphere as incidental nanoparticles. Engineered nanoparticles of carbon have a more regular shape and structure than in soot and are named fullerenes, carbon nanoparticles particularly tubes and graphene that are used in various applications. The primary categories of nanomaterials include inorganic non-metallic, organic carbon-­ based, metal NPs, polymer-based particulate materials, etc. (Contado 2015). In this chapter, we describe some of the widely used techniques for synthesis of nanoparticles. Thereafter, some of the commonly employed characterization methods have been discussed.

1.2

Synthesis of Nanoparticles

Nanoparticles are so far synthesized by two main approaches: bottom-up and top-­ down. Bottom-up is a constructive approach and is the build-up of material from atom to clusters to nanoparticles. Physical and chemical vapour depositions,

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pyrolysis, sol-gel, spin disc and biosynthesis are some of the commonly used bottom-up methods for nanoparticle production. Top-down is a kind of destructive approach in which a bulk material is reduced to nanoscale particles. Some examples of this approach are milling, nanolithography, thermal decomposition, etc. Further, these nanoparticles can be made by physical, chemical and biological methods. High-energy ball milling, inert gas condensation, pulsed vapour deposition, laser and flash spray pyrolysis are categorized under physical methods of preparation. Chemical methods are chemical vapour synthesis, microemulsion technique, sol-gel synthesis, polyol synthesis, hydrothermal synthesis, etc. The recent biological method comprises microorganisms and plant-assisted biogenesis.

1.2.1 Bottom-Up Synthesis Methods 1.2.1.1 Chemical Vapour Deposition (CVD) It is an inert gas condensation process which consists of depositing thin film of various material reactants in a gas phase on a heated substrate. The deposition is done in a chamber kept at ambient temperature by combining gas molecules. Chemical vapour deposition (CVD) occurs when a heated substrate reacts with the gas mixture (Carlsson and Martin 2010; Creighton and Ho 2001; Piszczek and Radtke 2018), as depicted in Fig. 1.1. This method produces highly pure, uniform films. However, requirement of ultra-high vacuum (UHV) deposition set-up and release of toxic gas by-products are some limitations. In the CVD process, photo-assisted and plasma-assisted methods as variants are also available. The parameters that affect film deposition are substrate material, temperature of the substrate, composition of the gas mixture used for reaction, total pressure, gas flow, etc. CVD process is a very efficient technique employed for coating silver nanoparticles on titania nanotube (TNT) layers for medical applications (Piszczek and Radtke 2018). This report suggests that by using CVD technique control of the size of silver grains and their position on the surface of the TNT matrix is possible. CVD of gold nanoparticles

Fig. 1.1  A schematic representing chemical vapour deposition (CVD) method of nanoparticle synthesis

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deposited on MCM-41 has also been carried out in order to study their catalytic activities for oxidation of CO and H2 at low temperature (Mitsutaka et al. 1998).

1.2.1.2 Sol-Gel Synthesis This is a simple bottom-up method which synthesizes nanoparticles in a cost-­ effective manner (Kumar et al. 2015). This process involves the chemical transformation of a sol (vent) into a gel state with further post-treatment and transformation into solid oxide material. The ‘sol’ is a colloid made of small solid particles suspended in a liquid phase. The ‘gel’ consists of solid macromolecule submerged in a viscous solvent. The method involves hydrolysis and condensation. Initially, the precursor is stirred continuously in a host liquid resulting in a mix of liquid-solid phase. Nanoparticles can further be phase separated by filtration, sedimentation and centrifugation. Then the moisture is removed by drying, as shown in Fig.  1.2. Advantages associated with the sol-gel process are lower processing temperature, high purity and uniform nanostructure, control of dopant concentration and ability to synthesize multicomponent compositions in different product forms. Many nanoparticles including Ag, Ti and Al prepared by sol-gel process demonstrate that annealing temperature is very crucial for the formation of nanoparticles (Ahlawat et al. 2014). In a separate work (Shahjahan et al. 2017) crystalline silver nanoparticles were synthesized by sol-gel technique. CH3COONa and hydrazine were used as reducing agents in water at room temperature. 1.2.1.3 Spinning Disc Reactor (SDR) This method to synthesize nanoparticles consists of a rotating disc mounted on a shaft inside a chamber in which various physical parameters can be controlled, as shown in Fig.  1.3. The reagent solutions are kept inside the reactor on this fast-­ rotating disc filled with inert gases or as required (Mohammadi et al. 2014). The spinning of disc leads to the fusion of atoms and the resultant mass obtained is first allowed to precipitate and then to collect and is further dried (Pask et  al. 2012). Synthesis of nanoparticles by this method has been reported to be monodisperse as compared to other methods. However, characteristics of the nanoparticles obtained depend on various parameters such as liquid flow rate, rotation speed, liquid-­ precursor ratio, location of feed and disc surface. 1.2.1.4 Pyrolysis Pyrolysis is the most commonly used process for large-scale synthesis of nanoparticles as it is a simple, cost-effective process with high yield. In this process, a precursor which is either liquid or vapour is burnt with flame into the furnace maintained at inert atmosphere, as depicted in Fig. 1.4. Products obtained after pyrolysis are either solids such as charcoal, biochar or liquids or non-condensable gases as H2, CH4, CO, CO2 and N. Nanoparticles can be recovered from the combustion gas by air classification. Some of the furnaces use laser and plasma in place of flame to produce quick evaporation. Silver nanoparticles (AgNPs) synthesized by flash pyrolysis using aqueous silver nitrate solution are fed from a burette to an atomizer, and the atomized spray is

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Fig. 1.2  The process of sol-gel synthesis resulting in formation of nanoparticles

discharged into the reaction chamber kept above 650 °C with a tube furnace. AgNPs are deposited on the substrate. A vacuum pump in the reactor that facilitates discharge of water vapour and exhaust gases to vent. Temperature inside the reaction chamber was monitored by various thermocouples installed at different places, e.g. near the surface of atomizer, near the reactor and at the sample holder (Pingali et al. 2005).

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Fig. 1.3  Working scheme of a spinning disc reactor (SDR)

1.2.1.5 Biosynthesis Biosynthesis is an eco-friendly approach for the synthesis of nanoparticles. The outcome is that the nanoparticles obtained are nontoxic and biodegradable (Mohanpuria et  al. 2008). Biosynthesis is an enzyme-based activity which uses microorganisms, e.g. bacteria and fungi, along with the precursors instead of conventional physical and chemical methods to produce nanoparticle, as represented in Fig.  1.5. Thus, this is a green route to synthesize nanoparticles having efficient properties which lead to various biomedical applications (Mandal et al. 2006). Apart from this, the method is very safe and can be used to control particle shape, size and structure (Li et al. 2011).

1.2.2 Top-Down Synthesis Methods 1.2.2.1 Laser Ablation This technique uses a laser to irradiate and remove material from a surface. Ablation indicates non-equilibrium vapour/plasma conditions created at the surface by intense laser pulse whereas evaporation means heating and evaporation of material in thermodynamic equilibrium state. In this technique, major parts of the equipment

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Fig. 1.4  An illustration of spray flame pyrolysis system and formation of nanoparticles

are ablation chamber, laser ablation device and a pulsed laser. Material on the surface of target vaporizes into laser plume due to the high-power laser light beam falling on the target. The vaporized material condenses to form clusters of nanoparticles which are deposited on a substrate or collected (Kim et al. 2017), as shown in Fig. 1.6. Laser ablation synthesis in solution (LaSiS), a more recent technique, is helpful in obtaining chemical-free nanoparticles for better applicability (Amendola et  al. 2007; Amendola and Meneghetti 2012). Various metal nanoparticles were reported to have successfully prepared by laser ablation (Duque et al. 2019; Zhang et al. 2017).

1.2.2.2 Sputtering Ions produced by numerous processes strike a target and eject the particles which are deposited on a surface (Ayyub et al. 2001; Nie et al. 2009), as demonstrated in Fig. 1.7. Nanoparticles thus produced can have various sizes and shapes depending

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Fig. 1.5  The process of biosynthesis of nanoparticles through reduction by extracts obtained from plants, fungi and bacteria

on the substrate type and temperature, material-substrate whether annealed, thickness of the layer, etc. Ag nanoparticles on substrates at room temperature have been grown by using direct current (DC) magnetron sputtering and the effect of varying sputtering conditions on grain size has been reported (Asanithi et al. 2012). Highly controlled metallic NPs in morphology using well-designed target systems, sputtering steps and liquid matrix materials have also been synthesized (Nguyen and Yonezawa 2018). Besides, sputter deposition of gold onto ionic liquids resulted in the formation of highly dispersed Au nanoparticles that can be deposited by sputtering gold onto ionic liquids without additional reducing and stabilizing agents (Torimoto et al. 2006).

1  Synthesis and Characterization of Nanoparticles Used in Consumer Products

Fig. 1.6  The experimental set-up of nanoparticle fabrication via laser ablation method

Fig. 1.7  Deposition of nanoparticle film on the substrate by sputtering technique

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1.2.2.3 Mechanical Milling Mechanical milling is a very straightforward, simple and widely used technique in the synthesis of various nanoparticles. For example, in high-energy ball milling (HEBM) process, the moving balls impart their kinetic energy to the material to be milled. This breaks their chemical bonds and ruptures the milled materials into smaller particles with new surfaces, as illustrated in Fig. 1.8. Milling media, speed, ball-to-powder weight ratio, type of milling, type of high-energy ball mill, atmosphere and duration of milling regulate the amount of energy transfer between balls and material during the process, thereby affecting physical and morphological properties of the resultant nanomaterials. The HEBM process sometimes involves very high local temperature (>1000 °C) and pressure (several GPa) conditions. Various processes that occur during milling can influence the nanoparticle formation. For example, plastic deformation controls the shape and fracture can decrease the size of the particles formed whereas cold welding can increase their size (Carvalho et al. 2013; Chakka et al. 2006; Kumar et al. 2016; Salah et al. 2011). Zinc oxide (ZnO)

Fig. 1.8  The processing of bulk material into nanomaterial by mechanical milling

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nanoparticles formed by using HEBM technique promise potential application as an efficient antibacterial material when modified structurally and optically. Cryomilling has been employed to fabricate AgNPs by green synthesis.

1.2.2.4 Nanolithography Lithography of the nanoscale deals with the art of producing nanodimensional materials at least in one dimension by etching, printing or writing. Some of the important techniques of nanolithography are electron-beam, optical, scanning probe and nanoimprint lithography (Pease 1992). In this process a light-sensitive material attains a desired shape or pattern by tailoring the portion using etching, printing, etc. by the help of light or electron beam, as demonstrated in Fig. 1.9. The major advantage of nanolithography is to produce a cluster from a single nanoparticle with desired shape and size. This is an expensive technique and requires complicated instruments. Gold nanoparticles (average diameters from 2 to 4.5  nm) in two-­ dimensional arrays having line widths