Handbook of Nanoparticles

Synthesis, structures, and properties of boron nitride (BN) nanoparticles and nanocapsules were reviewed. They were prepared by various synthetic methods, such as thermal annealing, chemical vapor deposition, and arc melting. The structural characterization was performed by X-ray diffraction, transmission electron microscopy, and theoretical calculations. The properties were also investigated and discussed. Multiply twinned nanoparticles were investigated for chemical vapor-deposited BN with hexagonal, rhombohedral, and cubic crystal systems. A process for mass production of magnetic nanoparticles encapsulated with BN nanolayers was developed. The nanocapsules exhibited soft magnetic properties and excellent oxidation resistances. These BN nanoparticle materials are expected as various applications for recording media, nanoelectronic devices, and sensors for biological devices with good protection against wear and oxidation.

The effective range, maximum deflection angle, interaction parameters, and energy deposition of secondary electrons emitted from a gold nanoparticle irradiated by photon beams were calculated by means of Monte Carlo simulations. Moreover, the low-energy electrons (LEEs) with energy range of 3–20 eV, produced when a gold nanoparticle is irradiated by photon beams, were studied. The author’s group used the Geant4-based computer code was used to simulate and track secondary electrons from a 100 nm diameter gold nanoparticle irradiated at monoenergetic photon beams of 35, 73.3, 660, and 1,200 keV and from 2, 50, and 100 nm diameter gold nanoparticles irradiated at polyenergetic photon beams of 50 kVp, 250 kVp, 1.25 MV, and 6 MV in water. To investigate the LEEs, secondary electrons emitted from a gold nanoparticle with diameter of 100 nm, interacting with photon beams with energies equal to 35, 73.3, and 600 keV, were simulated using the Geant4 code. The phase spaces of the secondary electrons produced by simulations were then used to simulate the LEEs in water using the NOREC Monte Carlo code. All secondary electrons emitted by the gold nanoparticle and all LEEs produced by each secondary electron were tracked in simulations. The author’s group compared the number of secondary electron emitted with and without the gold nanoparticle in water and found that the presence of gold produces more electrons, when irradiated by monoenergetic photon beams with particularly low energy (35 keV). As the photon beam energy was increased from 35 to 1,200 keV, the effective electron range increased from 24.7 to 5,060 μm, but the total number of emitted photoelectric electrons decreased by a factor of 270 per interacting photon. The maximum electron deflection angle relative to the incident beam decreased from 83.1° to 39.2°, and the stopping power of the emitted electron decreased from 1.42 to 0.24 keV/μm. For polyenergetic photon beams with 2, 50, and 100 nm diameter nanoparticles, the author’s group found that both irradiations of the 50 and 250 kVp photon beam caused significantly greater deposited energy surrounding the gold nanoparticle (three orders of magnitude) than the MV beams (approximately five times). The author’s group also found that a larger portion of deposited energy resided within a larger nanoparticle under the photon irradiation. From the LEE results, the author’s group found that the energy distributions of the LEEs from the gold nanoparticle do not vary significantly between different photon beam energies. In addition, the 660 keV photon beam produced more LEEs traveling to a longer range than photon beams of lower energies (35 and 73.3 keV). This higher energy deposition and longer range LEEs produced by the 660 keV photon beam can enhance the cell kill. These simulated results yield important insights concerning the enhancement of tumor cell killing in gold nanoparticle-enhanced radiotherapy. The aim of this chapter is to show that the irradiation of gold nanoparticles at lower monoenergetic and polyenergetic photon energies in the kV range will be more efficient for cell killing. This conclusion is consistent with published studies.

The debris which is generated following laser ablation of a bulk target material by an intense laser beam consists under certain conditions of nanoparticles. This technique has been established and developed especially in the last few years as an alternative method for the synthesis of nanoparticles with desired physicochemical and structural properties in the same way as other techniques such as colloidal chemistry, electrochemistry, spark current decomposition, and others are used for that purpose. In case the target material is immersed in liquid, a nanoparticle colloidal solution is formed. The main advantages of this method are that it does not require the use of chemical precursors for nanomaterial synthesis, it produces nanoparticle colloidal solutions which are stable without the need of adding into them any stabilizing surfactants and nanoparticles with bare (ligand-free) surfaces which are highly surface active, and it allows for an in situ functionalization of the synthesized nanoparticles with the desired ligands. In addition, the ablation plasma plume experiences an additional compression by the liquid which may result in the formation of nanoparticles which are characterized by metastable material phases, difficult or impossible to be produced by other methods. This chapter outlines the fundamental principles of the method and reviews the synthesis of nanoparticles out of different materials ranging from metals to semiconductors and ceramics, techniques for adjusting the sizes and size distribution of the nanoparticles such as particle fragmentation, the synthesis of alloy nanoparticles and magnetic nanoparticles, issues of productivity scaling up, and the synthesis of other nanomaterials.

Nano-emulsion systems consist of a suspension of liquid nanodroplets stabilized by surfactants. Nano-emulsions are very powerful and promising systems for numerous applications, since there are very stable systems and their formulation and characterization are not only very simple but also simply transposable for industrial scale-up. Owing to a liquid core (mainly oily core), nano-emulsions have appeared as an efficient solution to disperse and stabilize poorly water-soluble compounds in aqueous media, through their nano-encapsulation. The main emerging applications of nano-emulsions include the formulation of innovative drug delivery systems and/or contrast agents. In this chapter, we will present a state of the art of the different aspects of the nano-emulsion formulation: processes of fabrication, optimization of the processes, impact of the chemical nature of the compounds on the processes, stability, strategies for optimizing the stability, and characterization. Likewise, we will discuss the emerging technologies aiming the surface treatment of nano-emulsions, including polymer coating (e.g., for inducing stealth properties in vivo) or ligand grafting for active targeting.

Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), the second generation of SLNs, are colloidal drug carrier systems that can be used for controlled drug delivery via various administration routes. They introduce various advantages over traditional dosage forms and their colloidal counterparts. SLN and NLC products are available in the market of the European community, and lipid nanotechnology has been increasingly attracted by the industry. Moreover, studies on lipid nanoparticles have been focused on targeting of drugs to the specific sites of the body, thus surface modification and treatment of SLN and NLC in the last decades. Naturally, several parameters must be taken into consideration for design of well-performing formulations, which have a long-term stability. A lot of analytical methods, which give scientists extensive informations, are essential for characterization of SLN and NLC. Investigation of factors affecting their physicochemical properties and common techniques used for their characterization will be introduced in this chapter. Determination methods of particle size, particle charge, and surface characteristics, crystallographic and structural investigations, and imaging of SLN and NLC will be discussed. In vivo and in vitro experiments will also be summarized to describe future direction of researches.

Current nanoparticles synthetic methodologies are focused on greener aspects which eliminate or minimize the use of hazardous chemicals or conventional energy sources. Typical greener techniques involve the use of sonochemical, microwave, electrochemical, hydrothermal, supercritical solvents, biosynthesis, and solar energy. Among this sonochemical route of nanoparticles synthesis is a well-developed and well-explored area due to its simplicity and diverse applicability. Sonochemistry arises from acoustic cavitation which involves the formation, growth, and implosive collapse of bubbles in a liquid which create high pressure and temperature followed by high rate of cooling. These properties are often responsible for shape and size selective nanoparticles synthesis.Present chapter mainly focused on the basic concept of ultrasound and its application toward the synthesis of inorganic nanocrystalline materials like nanoparticles of metal, metal oxides, and metal sulfides. In addition, it covers the USP system for nanosize material synthesis.

Bioceramics are the materials which can enhance the quality and longevity of human life. Hydroxyapatite (HAP) is a readily considered bioceramic material for artificial bone substitution in biomedical field due to its compositional resemblance to the bone mineral and very good biocompatiblity. Recently, HAP has attracted significant interest in drug delivery and bone tissue engineering applications. The human cortical bone consists of biological HAP which is found within collagen as nanodimensional crystalline aggregates. There has been enormous effort in developing bioactive synthetic ceramics that could closely mimic the fine and complex structure of human bone. Though HAP is highly biocompatible and bioactive, it possesses poor mechanical properties. In order to overcome this drawback, attempts are made toward the synthesis of mineralized HAP. Several methodologies have been investigated and developed for the synthesis of pure and substituted HAP. Modern research deals with novel HAP nanostructure formulations with properties closer to those of living bone, aiming at improved and more effective biomedical applications. This chapter presents the facile and cost-effective synthesis methods of pure and substituted HAP nanoparticles such as sol–gel approach, hydrothermal techniques, etc., toward effective biomedical applications.

Chirality or handedness in matter at the nanoscale is an extremely attractive property that has important consequences over a wide range of phenomena in the fields of physics, chemistry, and life sciences. In particular, chiral metal nanoclusters, such as gold and silver, are interesting since the bulk phase of the metals is of face-centered cubic (fcc) structure and thus symmetric. The nanoclusters are commonly protected by a certain kind of ligands (typically chiral thiol molecules) on their surface, and a whole new range of optical and chiroptical properties has been observed. In this chapter, synthesis, size separation, optical/chiroptical responses, and mechanisms to explain the optical activity for the chiral monolayer-protected metal nanoclusters are described, which will highlight their importance in both fundamental research and potential applications. Circular dichroism (CD) responses of structurally well-defined, atomically monodisperse gold nanocluster compounds such as Au₂₅(SR)₁₈ and Au₃₈(SR)₂₄, where SR denotes thiolates, are also reviewed on the basis of total structures including the gold core and metal thiolate units so-called staple motif. Moreover, postsynthetic asymmetric transformation of optically inactive metal nanoclusters using chiral phase transfer or boronic acid-saccharide complexation, which readily bestows chirality onto the nanoclusters, is demonstrated.

Metallic nanoparticles have fascinated scientists for over a century because of their huge potential in nanotechnology. Today, these materials can be synthesized and modified with various structures which allow them to be applied widely in numerous branches of science. Nanomaterials could be single or multiple metals and have copious kinds of size, shape, and structure and, thus, lead to profusely beneficial properties. Understanding nanoparticle characteristics helps in validating the synthesis, deciphering the morphology evolution, improving the synthesis protocols, and comprehending the potential applications of nanoparticles. Among characterization technologies, X-ray techniques provide assessment of composition, crystal structure, surface state, bonding environment, and physical properties. For example, X-ray diffraction (XRD) is used for the determinations of crystal phase and crystallinity of nanoparticles; X-ray absorption spectroscopy (XAS) has been used to characterize unoccupied electronic states, the chemical composition, and bonding environment in nanoparticles; and many other X-ray techniques such as X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and small-angle X-ray scattering (SAXS) have revealed information on nanoparticle characteristics. This chapter will give an overview of the utilizations of X-ray techniques for metallic nanoparticle characterization as well as discuss the classification of X-ray techniques based on their general usages and principles. The assessments of nanoparticle characteristics using X-ray techniques will be concretely described.

The rate equations that describe nanoparticle formation have been derived on the basis of kinetic theory and statistical thermodynamics. In the formation processes, the critical size of the nucleus of the nanoparticle can be determined to be the nucleus generated under near-equilibrium conditions. Nanoparticles larger than the critical size can continue to grow; nanoparticles smaller than the critical size may become smaller by evaporation. However, under strongly nonequilibrium conditions such as the supersonic expansion of a neutral gas, the concept of a critical nucleus becomes irrelevant because the calculated critical size becomes smaller than the atomic diameter. Consideration of very small clusters from a kinetic standpoint is very important for understanding the early stages of nanoparticle formation under nonequilibrium conditions. In the present chapter, the rate equations that describe condensation and evaporation during nanoparticle formation and growth are described using molecular partition functions based on statistical thermodynamics. The equations are used to determine nanoparticle size, which accounts for the characteristics of the materials. The effects of size and surface treatment of nanoparticles are also described, the objective being practical application of this information.

Spectroscopic ellipsometry, is a very power full tool for accurately investigating the optical properties of nanostructured materials in thin film form. In this chapter, the effect of dimensions on the properties of various nanoparticles including metal oxides, sulphides etc., have been discussed and reviewed. Basic principles of optical characterization using spectroscopic ellipsometry are presented. Results of ellipsometric studies of nanoparticles in thin film form for the determinations of various optical constants like band gap, absorption coefficient, extinction coefficient, refractive indices etc., and their variation with wavelength are presented. Strengths and weaknesses of the ellipsometric techniques compared with other optical techniques are also discussed.

This chapter summarizes the synthesis of various types of nanoparticles as well as surface modifications of nanomaterials using hydrothermal and solvothermal methods. First, the definition, history, instrumentation, and mechanism of hydrothermal and solvothermal methods as well as the important parameters affecting the nucleation and crystal growth of nanomaterials are briefly introduced. Then, the specific hydrothermal and solvothermal methods used to grow oxides; Groups II–VI, III–V, and IV; transitional metals; and metal-organic framework nanoparticles are summarized. Finally, the hydrothermal and solvothermal strategies used for the surface modification of nanomaterials are discussed.

The biggest societal impact of pharmaceutical nanotechnology is related to “nanomedicine,” a promising new drug delivery mode which provides a higher therapeutic efficacy than conventional dosage forms due to increased drug bioavailability. Spray drying is commonly used in the pharmaceutical industry to convert a liquid phase (solution, emulsion, suspension, slurry, paste, or melt) into a dry, solid powder. In conventional spray drying, a feed product is atomized into a fine spray and dried by a hot inlet air stream. The contact between the hot inlet air stream and spray causes evaporation of solvent and drying of the spray into solid product in a single-step process. The widespread research investigation of nanoparticles as a mode of drug delivery has translated to the late development of spray drying technique with advancement focuses on atomization mechanism to produce discrete dried nanoparticles. This chapter describes spray drying processes and processors for particle production from micro- to nanoscale and highlights advantages of using spray drying as the process of nanoparticle manufacture, characteristics of spray-dried nanoparticles, and limitations of spray drying in drug targeting device manufacture.

Stimulus-responsive polymers, also known as “smart,” “intelligent,” and “environment-responsive” polymers, are a rapidly emerging class of materials that can respond to minor changes in environmental parameters such as pH, temperature, light, electric and magnetic field, salt concentration, and mechanical stress. This response is generally in the form of reversible transitions in shape, conformation, and/or hydrophilicity of the polymer. Nano-/microparticles prepared using smart polymers are of interest as their drug release characteristics can be modulated in response to external stimuli. This aids in controlling the release of encapsulated payloads until the particles reach the desired site. This book chapter attempts to summarize current research in the development of “smart” micro- and nanoparticles for various biological applications. It will also cover various parameters involved in smart particle preparation including polymers, surfactants, and methods used in nano-/microparticle formulation as well as surface modification and characterization of nano-/microparticles. Further, we will discuss recent research in dual-stimulus-responsive and theranostic particles for multiple therapies. The future scope of these particles and hurdles to overcome for translation to clinical research will also be briefly discussed.

Drug synthesis, high-throughput screening generates billions of poorly soluble drugs which are neglected in further developments due to solubility issues. In the last 20 years, nanonization by milling is being effectively used commercially to save these drugs by overcoming solubility problems in commercial way. Various labs at industry and academic level successfully investigated milling technique alone and in combination with other techniques to reduce particle size, thereby increasing the dissolution velocity of drug. Milling offers ease of production, efficient control of production parameters, freedom of small to industrial batch size, liberty to produce highly concentrated suspensions, and improved stability of final product. Nanonized slurries exhibited promising results in vitro and in vivo and many fold increase in bioavailability. Nanosuspensions are investigated for organ or cellular delivery in various diseases like HIV/AIDS, malaria, and other infectious disease conditions. The issue of metal abrasion and contamination is now nullified by effective engineering solutions. In this chapter, recent updates on milling techniques and their applications in pharmaceutical field are discussed.

Lasers are widely used for material processing (cutting, drilling, cleaning, film deposition, etc.). A recent application is for nanoparticle fabrication. Pulsed laser ablation is by far the fastest and clean method to fabricate nanoparticles directly from bulk targets. For this purpose, target ablation is performed in vacuum, in gas atmosphere, or in liquids with fast (nanosecond) and ultrafast (picosecond, femtosecond) laser pulses. Mostly metal but also semiconductor and ceramic nanoparticles were fabricated. In the early stage of this technique, the main problem was the large size distribution of the produced nanoparticles. But the possibility to independently handle laser pulse characteristics (wavelength, power density, pulse duration, etc.) and the accurate control and optimization of the ambient parameters is leading to an efficient tailoring of the nanoparticle size, due also to helpful theoretical and numerical models. A review is presented of the most important studies and of the obtained results.

In the past two decades, nanoparticles have been widely studied from fundamental and applications viewpoints. They have been used in a range of applications including chemical and biosensing, gene and drug delivery, and electronics, mechanical, and optical device fabrication. The synthesis of nanoparticles with controlled dimensions is important because the properties of nanoparticles are size and shape dependent. This chapter emphasizes template-assisted synthesis and characterization of nanoparticles. Template synthesis provides nanoparticles with controlled shape and size with high reproducibility and yield. The chapter also includes synthesis and characterization of different templates including nanoporous alumina and polymer membranes, zeolites, and self-assembled organic and biomaterials as well. The application of biosensing and bioseparation using nanoparticles is discussed in detail and special emphasis is given to single pore-based detection and sensing of nucleic acids and proteins.

Nanomaterials have attracted tremendous interest during the past two decades. Microfluidic technology offers an alternative strategy for the synthesis and characterization of nanomaterials with controlled properties. The convergence of nanomaterials and microfluidic technology affords an enormous opportunity for the further development of novel nanomaterials for various applications. This chapter covers recent achievements and the latest trends in the synthesis and characterization of nanomaterials using microfluidic technology.

Nanoparticles exhibit, from a magnetic point of view, various anomalies and specific magnetic properties, different from those of the bulk with the same chemical composition. Knowing the new magnetic properties is very important, both from theoretical point of view and their numerous practical applications in nanotechnology (nanotechnics and, recently, in nanomedicine), which should be considered. In this chapter we shall present an overview on the following topics: saturation magnetization, magnetic anisotropy, and magnetic behavior of magnetic nanoparticles, in relation with their size and magnetic structure, single- or multi-domains. The magnetic properties of the nanoparticles are compared and discussed in relation to those of the corresponding bulk. The surface effects, in the case of surfacted nanoparticles and those embedded in different matrices, on magnetic properties are presented and discussed in the core–shell model (core of the nanoparticle, where the magnetic moments are aligned under the exchange interaction, and the shell, where the magnetic moments are in a disordered structure).

Nanoparticles emit electrons and photons when they are excited by electron injection via electric current; electromagnetic radiation via microwave fields; laser radiation in infrared, visible and synchrotron (X-ray) ranges; and electron and ion bombardment. In each case, the emission mechanism depends on characteristic length scales of the nanoparticle. If the particle size is commensurate with it or is smaller, a size dependence of emission is observed [1–3]. Also, it is interesting that nanoparticles may demonstrate properties absent in bulk material.

In the last decades, nanoparticles have been of great research interest due to their unique quantum size effect and optical, electronic, magnetic, and supramolecular properties.In recent year, the face-selective adhesion of gold nanoparticles onto the crystal faces of organic crystals, also called “decoration” has been reported for first time. The organic single crystals may have surfaces with different chemical nature, allowing the opportunity to explore a wide variety of composite materials with highlights on anisotropic properties.The metal nanoparticle preparation methods can be classified as chemical and physical methods. Chemical methods consist mainly in the decomposition or precipitation of inorganic salts. For example, it is possible to obtain gold nanoparticles from a gold precursor like HAuCl₄. Physical methods involve principally the production of gas phase atoms or clusters by diving of the bulk material. Other remarkable preparation method is the sputtering, where a high-purity metal target is bombarded with argon ions, followed by the subsequent deposition of the sputtered metal atoms on the surface of a substrate support to create a uniform dispersion of nanoparticles. This technique has some advantages over other preparation methods like the no contamination from solvent or precursor molecules on the surface. Also, the process is economical and environmentally friendly, since the metal excess is recoverable from the chamber and without liquid waste.

Arrays of metal nanoparticles in an organic matrix have attracted a lot of interest due to their diverse electronic and optoelectronic properties. By varying parameters such as the nanoparticle material, the matrix material, the nanoparticle size, and the interparticle distance, the electronic behavior of the nanoparticle array can be substantially tuned and controlled. For strong tunnel coupling between adjacent nanoparticles, the assembly exhibits conductance properties similar to the bulk properties of the nanoparticle material. When the coupling between the nanoparticles is reduced, a metal insulator transition is observed in the overall assembly. Recent work demonstrates that nanoparticle arrays can be further utilized to incorporate single molecules, such that the nanoparticles act as electronic contacts to the molecules. Furthermore, via the excitation of the surface plasmon polaritons, the nanoparticles can be optically excited and electronically read out.

In this chapter, first, a survey on the early stages of electrochemical nucleation and growth is provided with special emphasis on recent discoveries which provide new insights on electrochemical nanoparticle formation. Then, a comprehensive review of nanoparticle electrodeposition from aqueous solutions is provided, analyzing the different electrochemical processes employed to obtain nanoparticle distributions with desired morphology and low size dispersion. Finally, the functional properties obtained with the resulting nanostructured materials are described.

The results on synthesis of nanopowders with different composition by laser ablation of target with eventual condensation of vapor in buffer gas flow and advantages of this method are reported. The optimal conditions of nanopowder production and the influence of pressure and kinds of buffer gas are discussed. The particle size distribution is presented, and the reasons of their similarity despite differing laser plume size and physical–chemical properties of material are pointed out. The characteristics of nanopowders produced by laser ablation are given, including chemical composition of nanoparticles, their sizes, phase composition, output rate, and specific energy demands. The main attention is given to nanopowders which are used in the fabrication of fuel cells based on solid solutions, laser ceramics, wastewater purification, etc. It is noted that at evaporation of targets sintered from several oxides, the excessive amount of low-melting component is registered. Nevertheless, the nanopowder of complex composition with deviation from demanded stoichiometry less than 0.2 % can be produced by selection of target composition and evaporation conditions.The particle size distribution and possibility of removing the largest particles are reported. It is noted that at the evaporation of targets with abruptly variable absorbance index (semitransparent targets), the mechanism of evaporation and the surface of targets are changed.

Melting temperature is one of the fundamental properties of materials. In principle, the melting temperature of a bulk material is not dependent on its size. However, as the size of a material decreases toward the nanometer size and approaches atomic scale, the melting temperature scales with the material dimensions. The melting temperature of a nanomaterial such as nanoparticles (isotropic) and nanorods/nanowires (anisotropic) is related to other fundamental physical properties for nanomaterial applications, including catalysts, thermal management materials, electronics materials, and energy materials.This book chapter focuses on both the theoretical and experimental studies of metallic nanoparticle melting temperature depression. Thermodynamic modeling and molecular dynamic (MD) simulations are discussed regarding the melting behavior of different nanostructures, such as spherical nanoparticles and nanowires. The currently available measurement techniques by using classical differential scanning calorimetry (DSC), recently developed nanocalorimeters, transmission electron microscope (TEM), and optical methods are introduced. In addition, the applications of metal nanoparticles with lower melting temperatures are discussed, such as nanosoldering and sintering for electronics assembly and packaging.

Sol-gel methods emerged by the 1940s when Geffcken and Bergen produced single oxide coatings and Schroeder first deposited thin films. Subsequently, scientists and engineers have used sol-gel processes, which drive individual particles or sols through a gelation process into a larger mass, in numerous applications. Recently, sol-gel processing techniques have extended to nanoparticle synthesis because sol-gel techniques are simple, are inexpensive, and may be used to tune material properties. This chapter critically reviews methods that have been widely used for decades and new cutting-edge strategies driving development of exciting, emerging technologies. Examples include tuning photon capture in solar cells, enhancing magnetic properties, and providing complex biosensing capabilities.

Metal nanoparticles, with a wide range of applications in catalysis and sensing, have structural and electronic properties that differ from those of their bulk macroscopic counterparts. Electrochemical techniques are of particular interest in the study of metal nanoparticles because electrons may undergo quantum confinement effects which are reflected in their electrochemical behavior, resulting, ultimately, in three distinguishable voltammetric regimes: bulk continuum, quantized double-layer charging, and molecule-like. Similarly, semiconductor nanoparticles (quantum dots, QDs) are receiving considerable attention due to their high fluorescence, which makes them of interest for biological and medical applications, among others. The semiconductor bulk materials possess defect states that originate from impurities, divacancies, or surface reactions as a result of their synthesis. Voltammetric features provide information on bandgap energy, the position of conduction and valence band edges, and the position of defect sites as well as on the interaction with the capping ligand. This chapter is devoted to provide a critical view of the current state of the art in the electrochemistry of such systems.

The J(ω) Raman spectra of the (GaN)₁₂₉, (SiO₂)₈₆, and (GaN)₅₄ (SiO₂)₅₀ nanoparticles as well as the optical properties of silicon dioxide and gallium arsenide nanoparticles and the four-component particles based on them were calculated using the molecular dynamics method. The spectrum of (SiO₂)₈₆ had three broad bands only, whereas the Raman spectrum of (GaN)₁₂₉ contained a large number of overlapping bands. The shape of Raman spectra for four-component particles depends strongly on the way the GaN-, GaAs-, and SiO₂-components are located in the nanoparticle. Increasing the temperature (from 300 K up to 1,500 K) of nanoparticles causes a significant rise in the intensity of the anti-Stokes part of the Raman spectrum. Heating the nanoparticles to 1,500 K does not lead to the shift of J(ω)-spectrum peaks for the (GaAs)₅₄ (SiO₂)₅₀ nanoparticle with SiO₂- coating. The refractive index and absorption coefficient as well as the number of optically active electrons depend weakly on the arrangement of the conductor (GaAs) and isolator (SiO₂) in the nanoparticle.

Designing an efficient and cost-effective catalyst is a subject of extensive research. This chapter describes a new fast-growing area of catalysis, viz., metal nanocatalysis. In the nanosize regime, metals show perceptible change in their electrical, optical, and catalytic properties which allows them to act as catalysts in various electron transfer processes as well as organic transformations. Metal nanoparticle (NP) catalysts exhibit superior reactivity and selectivity compared to their bulk counterparts. Additional advantages include easy synthesis and separation, tunable size and shape, as well as improved efficiency under mild and environmentally benign conditions in the context of green chemistry. These systems offer efficient protocols for sustainable and environmentally friendly future, leading to the development of active and selective materials for a wide variety of applications.

Due to their special physicochemical, optical, and biological properties, noble metal nanoparticles have huge potential for application in many different biological and medical areas, such as highly sensitive diagnostic assay, thermal ablation, radiotherapy, or carriers for drugs and gene delivery. This chapter selectively reviews the bio-functionalization of metallic nanoparticles and their recent applications in medicine. The chapter is divided into four sections: “Introduction,” “Bioconjugation of Metallic Nanoparticles,” “Cancer Therapy,” and “Gene Delivery.” After a short introduction, we present few general strategies for bioconjugation of metallic nanoparticles: physisorption, physisorption using mediator molecules, covalent binding of biomolecules to cross-linkers, covalent binding of biomolecules to nanoparticles, and linking of biotinylated biomolecules to streptavidin-functionalized nanoparticles. The third section presents the recent advances in cancer therapy based on two strategies: passive targeting and antibody targeting, using functionalized gold nanoparticles. The fourth section describes the gene delivery process, by which foreign DNA is introduced into the host cells. The process typically involves the formation of transient pores or “holes” into the cell membrane, which allows the uptake of foreign material. The main aspects that are discussed about the gene delivery process are the stealth character and the targeted recognition of tissues.

This review presents the results of the investigation of the interaction of optical (laser) radiation with spherical homogeneous and core–shell nanoparticles, absorption of optical radiation by nanoparticles, conversion of absorbed energy into nanoparticle thermal energy, the efficacy of nanoparticle heating itself, and heat transfer to ambient medium. Different homogeneous metallic (gold, silver, platinum, zinc, etc.) and core–shell (silica–gold, silver–gold, etc.) nanoparticles are considered. The models and results of computer and analytical calculations of nanoparticle heating by radiation pulse have been presented. The nonlinear dependences and comparative analysis of the thermo-optical properties of homogeneous and core–shell nanoparticles on parameters of radiation and nanoparticles are investigated.The results present the platform for the applications of thermo-optical properties of nanoparticles in photothermal nanotechnology, including light-to-thermal energy conversion and solar energy harvesting, laser nanomedicine, nonlinear optical diagnostics, laser processing of nanoparticles, etc.

We have proposed a next-generation simple method for water analysis with high sensitivity to trace ions at ppb levels, named “dye nanoparticle-coated test strip” (DNTS). The DNTS is loaded with a thin layer (400 nm ~ 3 μm) of indicator dye nanoparticles or nanocomposites on the top surface of a membrane filter and provides a remarkably concentrated color signaling surface. Therefore, almost all signals are available efficiently, but in contrast to conventional test papers, indicator dyes are distributed over the entire support. The DNTS is applicable not only to immersion test but also to filtration enrichment in which target metal ions are concentrated by passing sample solutions through it. In addition, we designed two fabrication methods of DNTSs for the purpose of producing a large number of test strips with various organic indicator dyes. One method is ideal for hydrophobic indicators and is based on nanoparticle preparation by reprecipitation method. The other is suitable for hydrophilic dyes and is based on the preparation of nanocomposite composed of a water-soluble dye and nano-adsorbent through electrostatic interaction and the following aggregation. By simple filtration of the respective nano-dispersions with a fine membrane filter having microscopic pores, various kinds of DNTSs are available.

Lipid-based nanosystems have gained interest as matrixes able to dissolve and to control delivery of active, thereby improving their bioavailability and reducing side-effects.In particular, nanoparticles based on lipids have been widely proposed as novel drug carrier systems.For instance, solid lipid nanoparticles (SLN) add up the benefit of colloidal lipid emulsions and those of solid matrix particles. Nanostructured lipid carriers (NLC), the second generation of SLN, are a blend of a solid lipid matrix and a liquid lipid phase.Among lipid dispersion providing matrixes for the sustained release of drugs monooleine aqueous dispersions (MAD) can be mentioned. MAD are heterogeneous systems generated by the dispersion of an amphiphilic lipid, such as monoolein, in water. MAD are made by a complex lyotropic liquid crystalline nanostructures such as micelles and lamellar, hexagonal, and cubic phases.In order to characterize nanosystems, it is important to carry out detailed systematic investigations. X-ray diffraction and microscopy give information about shape, inner structure and dimensions of powders, and dispersions that could not otherwise be identified.This chapter provides an overview about the use of x-ray diffraction and cryogenic transmission electron microscopy as techniques for characterizing lipid nanosystems recently developed by our research group.

A series of studies have been carried out for delivery and controlled release of genes, miRNAs, peptide structures, siRNAs, and pharmacological agents to the target tissues through different nanoparticles. Agents to be delivered are either attached on or entrapped in nanoparticle structure. In the delivery process, the nanocarriers face many different delivery tasks and different physiological microenvironments. Considering the changes in the environment, nanocarriers are designed and synthesized in such a manner that enables these structures to overcome the challenges faced during delivery. In this chapter nanoparticle structures as cationic lipids, polycationic polymers, and dendrimers used in drug and gene delivery are reviewed.

Nanoparticles are widely utilized in the fields of medicine and industry. Accordingly, it is vital to deliberately assess the toxicity of nanoparticles in the development of nanoparticle-related products and therapeutic agents. This chapter reviews in vitro and in vivo procedures for the assessment of the toxicity of nanoparticles. As the first step, various in vitro and in vivo procedures are listed and discussed with suggestions from various researchers. Furthermore, we discuss the issues regarding the determination of toxicity assays for the evaluation of the toxicity of nanoparticles. Especially, these assays are valuable tools to investigate the differential effects of nanoparticles of various sizes and different surface modification. We expect that this chapter can be a stepping stone for further discussion about the toxicity of nanoparticles and will help researchers to evaluate the toxicity of nanoparticles efficiently.

Nanobiotechnology has been demonstrated to be an efficient tool for targeted therapy as well as diagnosis, with particular emphasis on brain tumor and neurodegenerative diseases. On this regard, the aim of this chapter is focused on engineered nanoparticles targeted to the brain, so that they have the ability to overcome the blood–brain barrier (BBB) and enter the brain tissue. Firstly, it highlighted the difficulty of physically active molecules and colloidal carriers to overcome BBB, which is an impediment for the treatment of several brain diseases; then, the use of nanoparticles as advantageous carriers to cross the BBB and achieve brain, and their functionalization strategies are described; and finally the delivery of nanoparticles to the target moiety, as diagnostics or therapeutics. Therefore, this chapter is focused on how the nanoparticle surface may be functionalized for drug delivery and diagnostics. Furthermore, it is also mentioned that some BBB targets were already used as transport mediators to central nervous system by functionalization on nanoparticles. It summarizes the nanoparticles potential in therapeutics and molecular targeting to BBB, and also an approach of the nanoparticle-mediated drug transport across the BBB, where nanoparticles take advantage of physiological receptor-mediated transport processes.

Nanoparticles of three different categories of condensed matter, namely, metal, semiconductor, and insulator, exhibit fluorescence through radiative recombination of charge carriers though the origin and mechanism of light emission is vastly different. Whereas fluorescence from metal nanoparticles, e.g., Au and Ag, falls in the visible region due to sp–d band transition of electrons, the fluorescence gets enhanced due to interaction with localized surface plasmon. Semiconductor quantum dots form a special class of fluorescent materials where the emission color can be tuned by tailoring the particle size as a manifestation of quantum confinement effect. Doped semiconductor nanoparticles offer another category of multifunctional materials with tunable emission and desired electronic/magnetic properties. Rare earth-doped insulators are conventionally used as phosphors for various display and lighting applications. Nanoparticles of various rare earth-doped complex insulators emit intense monochromatic light and can be synthesized by various techniques such as sol–gel, wet chemistry, coprecipitation, hydrothermal, etc. Synthesis and elimination of surface states by passivation/capping play an important role in arresting non-radiative pathways to augment fluorescence efficiency of nanoparticles.

In recent years, nanotechnology has emerged as a novel tool for application in various fields of electronics, photonics, magnetic, biomedicine, optics, etc. The ability of nanoparticles to serve as a versatile application tool could be attributed to their unique physicochemical characteristics that significantly differ from their bulk counterparts. Nevertheless, their tendency toward aggregation results in reduced reactivity and longevity which in turn exerts negative impact on their application potential. To overcome this constraint, several surface modifications and particle stabilization methods have been developed using various kind additives such as surfactants, polymers, water-soluble starch, carboxymethyl cellulose, cellulose acetate, polyacrylic acid, etc. These additives effectively control the shape and size of nanoparticles, enhance nanoparticles’ stability and mobility, and thereby increase the nanoparticle efficiency. The present chapter provides a brief overview of recent developments in stabilization methods, modification approaches, additives used for stabilization of nanoparticles with special reference to polymers and surfactants, and their mechanism of action. The significance of different additives in relation to nanoparticle efficiency in degrading/reducing environmental contaminants will also be addressed.

Drug molecules often display little affinity for nonhealthy tissues and/or cells, leading to inefficiency, and high incidence of severe side effects. To face the problem, numerous strategies have been postulated, i.e., chemical modifications to the drug molecule, and proper engineering of drug nanocarriers. In this line, the introduction of poly(d,l-lactide-co-glycolide) nanoparticles in the drug delivery arena has been hypothesized to optimize drug biodistribution and concentration into the targeted site, thus improving the therapeutic effect while reducing the associated drug toxicity. Recent advances in the field have been devoted to the optimization of the in vivo fate and effectiveness of poly(d,l-lactide-co-glycolide)-based drug nanocarriers, i.e., by passive targeting strategies based on the functionalization of the particle surface with special biomolecules, and/or active targeting stratagems thanks to modifications leading to stimuli-responsive nanoparticles. In this chapter, we analyze the current state of the art and future perspectives in the formulation of poly(d,l-lactide-co-glycolide)-based nanomedicines against severe diseases.

This work reflects the need to have information on physicochemical properties of pharmaceutical nanoparticles and their interaction with biological systems, especially properties like particle size and surface functionalization that give special features when nanoparticles go through membranes, during opsonization, against immunogenicity, different toxicities, etc. This work aims to help new researchers to better understand the close relationship between pharmaceutical nanoparticles and their properties and their effects on biological systems and also contribute to nanotechnologists to take into account this situation and be aware that their responsibility does not end with the development and manufacture of these nanosystems.This chapter was written for specialist in different areas to enrich its content, and it is not the vision of a single author. We collaborated in this document nanotechnologists, toxicologists, and pharmaceutical technologists to give a critical approach to the imminent progress of nanotechnology in many areas of the knowledge such as pharmaceuticals, cosmetics, foods, chemical industry, computer industry, etc. Interaction of nanoparticles with human tissues, plants, animals, soils, water, air, etc. is inevitable because in the future, nanoparticles will be an important source of pollution and we must know how they interact with the surroundings depending on their physicochemical properties. Currently, a new branch of Nanotechnology called Nanotoxicology has been developed to deal with these dilemmas and in the future will be much more important than nowadays. Standardized protocols must be established to evaluate the cytotoxicity and genotoxicity caused by nanostructures.

The incorporation of organic compounds onto the surface of nanoparticles (NPs) differs from the same reactions carried out on macroscopic surfaces in that the former are characterized by surfaces energies much higher than the latter. Consequently, surface stabilization mechanisms of NPs are very active, and among them NP self-aggregation is the first and most important. In NP surface modification, the ability of the experimental conditions to destroy self-aggregation will determine the extent to which the NP surface is modified and so, the modified NP nature. A second consequence of the high-surface free energy is the NP surface avidity to interact chemically or physically with other compounds: NPs readily adsorb water, gases, vapors, or other higher molecular weight substances, and in the particular case of hydroxylated NP, chemical reactivity is both high and rich. This chapter will deal with the surface modification of silica, sepiolite, and polysaccharides. Experimental strategies, resulting organo-NPs, their structure and properties, and frequent uses and applications of them will be reviewed.

Metal nanoparticles are materials of great scientific interest with a vast number of applications. In catalysis, also including electrocatalysis, the use of metal nanoparticles has provided very remarkable advances, and they are being applied in many reactions to obtain enhanced catalytic activity and/or to modify their catalytic selectivity. Nevertheless, in order to optimize/modulate these (electro)catalytic properties, it is frequently required to have a fine control of their surface. In this chapter, different surface treatment strategies for metal nanoparticles and their effects from a catalytic point of view are reviewed. Finally, a brief section devoted to the use of metal nanoparticles as platforms for biomolecules attachment for biosensing and bioanalytical applications is also included.

The quantum dots (QDs) have excellent photophysical properties and recently being used for chemosensor and biosensor development. The high sensitivity and good selectivity is the main criteria for sensor development. In this intension, many research groups have decorated the organic ligands on the surface of QDs using the ligand exchange reactions. In the assembly of QDs decorated with organic ligands; the organic part is responsible for binding events, while QDs are generally acting as signaling subunit. The changes in the photophysical properties in signaling subunit is evaluated through absorption and fluorescence spectroscopy. The chapter is devoted to review systems, where: (a) photophysical properties of QDs are influenced by the coating of organic ligands; (b) photophysical properties of organic ligands has been influenced by coating these materials on the surface of QDs; (c) chemosensor/biosensor development using the photophysical properties of QDs and organic ligand assembly.

The efficiency of colloidal metallic particles in catalysis is closely related to their stability in the course of reaction. The choice of the capping agent is therefore critical as it controls both the size and shape of the particles, but also the dispersion of the metal core, while providing long-term stability. Among the wide variety of protective agents, cyclodextrins (cyclic oligosaccharides formed of glucopyranose units) have proven to be effective for synthesizing metallic nanoparticles by bottom-up chemical processes. The first examples in the literature emphasize the use of native cyclodextrins as metal nanoparticles (NPs) stabilizers but major improvements concerning the stability and catalytic activity of NPs either in the form of colloidal suspensions or immobilized onto supports were done by using chemically modified cyclodextrins. Indeed, appropriate functionalizations can lead to beneficial effects in the cyclodextrin affinity toward metal species and mass transfer of the substrate during the catalytic processes. It clearly appears that cyclodextrins can act as multitask agents from the formation (growth and nucleation process) of metal nanoparticles to the catalytic activity enhancement via specific interactions with the substrate. They can also be used to form supramolecular adducts with inorganic metal salts leading to heterogeneous catalysts with a homogeneous particles dispersion onto the support.

Metal-based micro and nanostructured materials are used in a variety of food-related applications as nutrient bioactive delivery systems texture and flavor encapsulation, microbiological control, and food packaging. In this chapter, we are focus on metal-based micro- and nanostructured materials incorporated into food-contact surfaces and packaging polymers. Heavy metals are effective antimicrobial agents in the form of salts, oxides, colloids, and complexes such as silver zeolites. Although it is not a metal base composite, montmorillonite (MMT) is widely used in industrial processes, in particular in metal-based micro- and nanostructured materials (MMT-silver) for food packaging applications. Silver-based nano-engineered materials are currently the most common nanocomposites used in commodities mainly due to their antimicrobial capacity. Copper, zinc, and titanium nanostructures have shown promise in food safety. Titanium dioxide is resistant to abrasion and UV-blocking capabilities. Copper has been shown to be an efficient sensor for humidity with antibacterial properties in active food packaging. Other important properties in active food packaging, which can be positively influenced by metal-based micro- and nanostructured materials, are ethylene oxidation and oxygen scavenging. In this chapter, we review synthesis methodologies and properties of the metal-based nanoparticles used in food-contact materials. Size, shape, crystal structure, surface functionality, and composition will determine their mobility and biological activity in different systems. Migration between ions and nanoparticles from the polymer matrices is one key point to determine their antimicrobial effectiveness; however, this migration may affect the consideration status of the polymer as a food-contact material.

Nanofluids are two-phase systems consisting of a carrier medium (gas or liquid) and nanoparticles. Due to very small sizes and large specific surface areas of the nanoparticles, nanofluids have superior properties therefore they have applies successfully in different technologies including MEMS- and nanotechnologies. One of the nanofluids theory key problems is the nanoparticles diffusion in liquids and gases. The object of this review is the systematic description of the features of the nanoparticle diffusion in gases and liquids. In particular, it is discussed: (i) The diffusion and thermal diffusion of nanoparticles in rarefied gases; (ii) The kinetic theory of nanoparticles diffusion in gases; (iii) Diffusion of nanoparticles in dense gases and liquids; and (iv) Mechanisms of the nanoparticle velocity relaxation in gases and liquids. It was shown that in general case the diffusion of nanoparticles in fluids is differed from diffusion of molecules and Brownian particles.

With the development of nanoscience and nanotechnology, manufacturing is undergoing revolutionary changes. Nanoparticles, due to their novel and often enhanced properties, are now more and more used in manufacturing. In this chapter, the state-of-the-art application of nanoparticles in manufacturing is reviewed. The contents include five parts: (a) role of nanoparticles in manufacturing, (b) manufacturing methods, (c) applications, (d) challenges, and (e) conclusions. The roles of nanoparticles are divided into three categories: (i) building blocks, being the major component of a manufactured product by solid-state or colloidal nanoparticle consolidation; (ii) functional filler, as an addition for functionality, such as property improver, catalyst, stimuli-responsive, sensing, imaging, and carrier; and (iii) nanocomposites for multifunctionality. Various manufacturing methods and novel trends are summarized in this chapter, including top-down and bottom-up, from 2D to 3D, from cleanroom to desktop, 3D printing, and bio-assisted methods, such as DNA origami. Direct applications in areas of flexible electronics, molecular electronics, solar cells, construction industry, water treatment, and biomedical devices are presented. The associated challenges including nanoparticle safety issue, sustainable manufacturing, economic issue, and scale-up are discussed.

This chapter gives an overview of the main methods available to transfer hydrophobic inorganic nanoparticles (metal, oxides, and semiconductors) into water such as place exchange of the capping agent, intercalation strategy with amphiphilic compounds or direct synthesis in the presence of those, and silica coating. The underlying principles are presented for each method, including respective advantages and drawbacks.

Mass spectrometry (MS) has been one of the most successful analytical techniques as it could provide highly sensitive detection and molecular structure information by recording MS or even MSn spectra. For MS analysis, efficient ionization, interference-free detection, and development of new ionization sources are of great concern in the fields of analytical and bioanalytical chemistry. Nanoparticles (NPs), with large surface area, specific physical and chemical properties, as well as techniques of controllable synthesis and functionalization, begin to attract more and more attentions for their potential application in MS analysis. On the one hand, NPs are useful matrixes in surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), mainly benefitting from their strong light absorption in wide range. Compared with conventional organic matrixes, NPs can eliminate the “sweet spots” and provide high signals in low-mass region. Besides, after functionalized with recognition ligands, NPs would gain a strong affinity to analytes, thus enriching the target compounds and improving the detection sensitivity. So far, silicon NPs, metallic NPs, metal oxide NPs, and carbon-based NPs have demonstrated their applicability in SALDI-MS, which are summarized in the following text. On the other hand, NPs can also be used for the development of new ionization sources. Nanostructure-initiator mass spectrometry (NIMS) is a novel spatially defined mass analysis technique that uses “initiator” molecules trapped in nanostructured surfaces to release and ionize samples on the surface. Owing to the advantages of high lateral resolution, high sensitivity, matrix-free, and reduced fragmentation, it is now widely used in biochemical analysis and tissue imaging. Based on the survey of literature, the authors also discussed the prospective of NPs used in MS analysis.

The remarkable physicochemical properties of gold nanoparticles (AuNPs) have prompted development in exploring biomolecular interactions with AuNPs-containing systems, pursuing biomedical applications in diagnostics. Among these applications, AuNPs have been remarkably useful for the development of DNA/RNA detection and characterization systems for diagnostics, including systems suitable for point of need. Here, emphasis will be on available molecular detection schemes of relevant pathogens and their molecular characterization, genomic sequences associated with medical conditions (including cancer), mutation and polymorphism identification, and the quantification of gene expression.

Nanotechnology has led to the development of new and improved materials, and particular emphasis has been directed toward nanoparticles and their multiple bio-applications. Nanoparticles exhibit size-, shape-, and composition-dependent properties, e.g., surface plasmon resonance and photothermal properties, which may potentially enhance laser desorption/ionization systems for mass spectrometry-based analysis of biomolecules. Also, nanoparticles possess high surface to volume ratio that can be easily derivatized with a wide range of ligands with different functional groups. Surface modification makes nanoparticles advantageous for sample preparation procedures prior to detection by mass spectrometry. Moreover, it allows the synthesis of affinity probes, which promotes interactions between nanoparticles and analytes, greatly enhancing the ionization efficiency.This chapter provides a comprehensive discussion on the use of nanoparticles for mass spectrometry-related applications, from sample preparation methodologies to ionization surfaces. Applications will focus on nanoparticle size, composition, and functionalization, as a comparative point of view on optimal characteristics toward maximization of bioassay efficiency.

Fluorescent metal nanoclusters are an emerging class of multifunctional materials engineered at the single-atom level, with dimensions approaching the Fermi wavelength of electrons that offer competitive functionalities of traditional semiconductor QDs including tunable emission, ease of conjugation, extended photostability, and high quantum yield. With the additional advantages of being composed of nontoxic/biocompatible materials, function with a fraction of the metal content, greatly reduced size for enhanced cellular uptake, opportunity for two-photon absorption at biologically relevant wavelengths, and demonstrated renal evacuation efficacy for in vivo applications, metal nanoclusters hold substantial promise. More recently the development of hybrid atomic cluster synthesis routes has expanded the materials’ multifunctional capabilities. This chapter will summarize the current high-yield synthesis and functionalization strategies for producing monodisperse pure metal and hybrid nanocluster materials from both wet chemistry and newly developed biomediated nanocluster synthesis methodologies, involving protein and DNA hosts. The role of the bio-host and surface functional groups on the nanoclusters formation, stability, and physical properties will be detailed through recent experimental and theoretical simulation efforts.