Nanoparticles: Applications and Impact on Science

Nanoparticles (NPs) functionalised with cores composed of inorganic and organic materials like noble element, magnetic metals, their alloys and oxides, and semiconductors are ehaustively studied and have huge potential for application in various areas. The spectrum of applications are endless and embraces nano-biomedicine, nanoprobes for diagnostics to treatment of diseases, nanobots for early detection of neoplastic cell, nano drug delivery systems, Nanosuspension, SPION, nanolithography for nanoelectronics industry, electrochemical sensing supported by gold nanoparticles impregnated halloysite nanotube composites and latent fingerprint detection for forensic investigations are to call a few. The effects of nanoparticles ought to be predictable and controllable, and bear the specified result with minimum cytotoxicity. These criteria are met by the careful craft of the core shell, allowing stabilization, specific targeting and recognition of biochemical species. This review is focused on the synthesis and functionalisation of a wide range of nanoparticles for various applications.

Keywords: nanoparticles, SPION, nanobots, halloysite, nanodrug delivery system forensic investigators, nanoelectronics.

1.INTRODUCTION:

The incredible accomplishments created within the discipline of material science and nanotechnologies over the past decade have had a significant impact on the biological, physical, and, chemical sciences. Recent developments in the life sciences rely profoundly on the supply of latest state of the art experimental tools and devices that modify and manipulates biomolecules and avail the study of complex biological processes at the molecular and cellular levels. Significant progress created inside the synthesis of fluorescent semiconductor Nanocrystals (NCs), further brought up as quantum dots (QDs), aboard an extra robust understanding of their nonlinear photo physical properties and then the event of biocompatible surface chemistries for their solubilization, have provided new imaging probes with monumental potential for scientists in the biological domain [1-3]. The distinctive optical properties of these semiconductor Nanocrystals make them exceptional fluorescent biological markers.

The leptons in QDs are confined in all three dimensions, resulting in a powerful size dependency of optical behavior like absorption, transmission and, consequently, emissive energies [4]. The radiative recombination of the charge carriers that ends in fluorescence emission once the lepton falls into the valence band is greatly inflated by quantum confinement, compared with their bulk semiconductor [5-8]. Thus, by reducing the dimensions of certain semiconductors to a couple of nanometers, new fluorescent probes may be obtained entirely different from their bulk counterpart. Additionally, by varying the nanometric size a greater control over the fluorescent properties of these probes like their emission wavelength can also be achieved to utilise its complete spectral potential [1].

Nanoparticles are constructs that possess distinctive physical and chemical properties associated to their size domain of 1–100 nm or a minimum of one dimension need to fall in the regime of 1-100 nm. NPs consist of a spread of materials as; metallic nanoparticles of noble metals of Gold / Aurum (Au) [9], Silver/ argentous (Ag) [10,11], atomic number 46 (Pd) [12], atomic number 78 (Pt) [13],magnetic compounds (viz. Co [14], Fe₃O₄ [15,16], FePt [12], CoFe₂O₄ [17], CoPt [18]), semiconductors (viz. CdS [19], CdSe [20], InGaAsP [21], GaAs [22], GaAsP [23], ZnS [24], TiO₂ [25], Lead Sulphide (PbS) [26], Indium Phosphide (InP) [26], Silicon (Si) [27]), core shell (viz. CdS/CdSe [28], CdSe/ZnS [29], CdS/ZnS [30], CdSe/AgS [31], HgS/CdS [32], PbS/CdS [33, 34], CdS/HgS [35], ZnS/CdSe [36], ZnSe/CdSe [37]) and different nanocomposites nanomaterials (viz. Co/WC and Fe/TiC). Therefore, as for the NPs to be useful in biomedicine, they need to satisfy certain criteria. For in-vitro applications like fluorescent staining of proteins and TEM imaging, NPs ought to trounce the traditional agents whereas having minimal toxicity. In-vivo, NPs got to be compelled to avoid non-specific interactions with plasma proteins (opsonisation) and either evade or allow uptake by the reticulo endothelial System (RES) hoping on the applying, to attain their meant target efficiently. They need to in addition maintain homogeneity and stability under physiological conditions, ideally within a good spectrum of pH. NPs carrying a payload, like drug molecules or de-oxyribonucleic acid (DNA) for cistron treatment ought to avoid premature release, at the same time should precisely deliver the load to the desired site. To accomplish these phenomenon Surface Chemistry of the NPs should be well known and modified accordingly for specific interactions with biological moieties of interest.

Nanoparticles-based drug delivery system provides many blessings, like enhancing targeted drug delivery, resulting in drug-therapeutic efficiency, reduction in dosage quantity, and pharmacological characteristics. Moreover, nanoparticles additionally improve the solubility of sparingly soluble drugs,dramatically alter pharmacokinetics mechanism, enhances drug half-life by reducing immunogenicity, increases specificity towards the target cell or tissue (therefore reducing facet effects),improve bioavailability, diminishing drug metabolism, providing controllable release of therapeutic compounds and in addition the delivery of two or more drugs at an equivalent time for combination medical aid [38,39].In the field of qualitative analysis, UV, FTIR-ATR [5] shows a stimulating spectral improvement in peaks of sample analytes rendering a quicker analysis even from a trace evidences. DC magnetron sputtering of nanoparticles on noble metals like Gold and Silver on samples of forensic evidences viz: blood, semen, spittle and latent fingerprints shows an enhanced and improved spectrum under ultraviolet light, FTIR-ATR and UV/VIS spectrum measurement devices. The spectral improvement is a result of Quantum confinement effect [40] of nanoparticles.

This article is split into three sections of: Pharmaceutical applications, Engineering and Technology and additionally the foremost expected field of forensic investigation. The article in addition presents current and futuristic market potential for Nanomedicine and numerous different nanoelectronic devices and its impetus impact on humanity.

2. Pharmaceutical Applications of nanoparticles

The potential application of nanoparticles is in the field of Nanomedicine. Nanomedicine as the name indicates is the branch of nanotechnology that deals with medical application of engineered nanotechnology. Though, the definition of nanotechnology and Nanomedicine continues to be an open debatable field, contention and brain storming among academicians and industrialists; we might wish to advocate wide accepted definitions by variety of the reputed regulatory authorities, research institutes and government agencies across the world.

United States Food and Drug Administration (USFDA) outline nanotechnology as:

Technology which allows scientists to create, explores, envision, and manipulate materials scaled in nanometers (10^-9 m). Such engineered materials can have an entirely different set of properties (physical, chemical and biological) that dissent from those of their larger counterparts [41].

National Institute of health in its ‘National Institutes of Health Roadmap for Medical research in Nanomedicine programme’ defines Nanomedicine as:

“An offshoot of nanotechnology, [which] refers to highly specific medical interventions at the molecular scale for curing disease or repairing damaged tissues, such as bone, muscle, or nerve” [42].

European Science Foundation’s (ESF) Forward Look Nanomedicine program has given comprehensive definition of Nanomedicine as:

Nanomedicine uses a set of nano-sized tools for the diagnosing, preventing and treating of disease and to gain insight and in-depth understanding of some of the complex underlying patho-physiology of disease. The ultimate goal is to improve the quality-of-life [43].

Since last two decades Nanotechnology has evolved as the most promising engineering technology in novel drug delivery systems and in diagnostic techniques. The very fact may be determined by the number of promising Nanomedicine candidates approved by completely different regulatory authorities across the world for these applications. The Nanomedicine here represents umbrella term that covers the molecules at a lower place the scale of one thousand nm in at least one dimension and has potential applications among the subsequent fields:

1. Advanced and targeted drug delivery
2. Real time imaging and diagnosis
3. Regenerative drugs.

2.1 Nanoparticles for site dependent and targeted Drug Delivery

The size confluence of nanoparticles with proteins is the major reason that nanoparticles are widely used in therapeutic applications [63]. Their huge surface area provides a binding site for displaying surface functional groups like ligand. Moreover, they possess a speedy absorption and unleash behavior provided by high skills of their diffusion and surface modification. Nanoparticles in its synthesized form are rarely used in biomedical application on account of its inherent properties viz: cytotoxicity and high surface charge. Their high toxicity destroys healthy cells and enormous surface charge renders them highly unstable prohibiting its medical application. Therefore, the particle size and surface characteristics of nanoparticles are in general tailored or controlled to suite user needs and medical interests. Some distinguished examples of surface modification of nanoparticles are covalent binding between surface and functional molecules or polymers, electrochemical sensors: added gold NPs and halloysite nanocomposites [44] and layer-by-layer (L-b-L) self assembly. Whereas organic, inorganic or organic/inorganic hybrid materials are used for the fabrication of nanoparticles, polymeric nanoparticles have in