Green synthesis of nanoparticles: current prospectus

Abstract

In the past few years, nanoparticles have been applied in various fields of science and technology, ranging from material science to biotechnology. Thus, the synthesis of nanoparticles can be considered as a dynamic area in research and application of nanoparticles. The different methods of nanoparticle synthesis include physical, chemical and biological methods. Of these methods, the biological synthesis is to be comparatively widely used due to its advantages of being low cost, non-toxic and environmental friendly. Bioapplications of nanoparticles have pawed way for green synthesis of nanoparticles. In this review, we have provided brief information on various biological agents used for the synthesis of nanoparticles.The various methods for nanoparticles synthesis are categorized mainly under physical, chemical and biological synthesis. Each of these methods has its advantages and disadvantages in terms of yield potential, scalability, particle size and distribution, shape uniformity and costs involved. Physical synthesis of nanoparticles:Nanoparticles of various materials, such as silver, gold, lead sulfide (PbS), fullerene, etc, have been produced using the evaporation/condensation technique [4]. The physical methods for nanoparticles synthesis include thermolysis, physical vapor deposition (PVD) [5], pulsed laser method [6], microwave-assisted synthesis [7], high-energy ball milling [8], melt mixing [9], laser ablation [10], ion implantation [11], sputter deposition [12], electric arc deposition [13],etc. Each of these techniques alters one physical parameter; for example, temperature is altered in thermolysis, pressure in ball milling, pH in ion implantation, radiations in laser ablation, etc. The desired size and shape of the nanoparticles can be obtained by optimizing and maintaining the optimized parameters. However, the main drawbacks of physical methods include high costs of equipments, time-consuming procedures, and elevated parameters that are not favorable to the natural environment, but the advantage of this method is that it can help obtain uniform shape and size of nanoparticles. Chemical synthesis of nanoparticlesChemical synthesis is one of the most widely used methods of producing large quantities of nanoparticles within a short span [14]. These methods include the sol-gel process [15], co-precipitation [16], chemical vapor deposition [17], radio-frequency plasma method [18], and solvo-thermal synthesis [19]. These methods require strong reducing agents for the reduction of nanoparticles and capping agents, such as triethanolamine, oleic acid and thioglycerol, [20] for size control and stabilization of the synthesized nanoparticles. The main disadvantages of chemical methods include high toxicity and cost of chemicals used.

Antibacterial activity of royal jelly-mediated green synthesized silver nanoparticles

“…Green synthesis (GS) strategies of metal NPs are safer alternatives to the conventional chemical and physical methods with a low environmental footprint and mild experimental conditions. It includes mild temperature and pressure and non-toxic, environmentally benign solvents, reducing agents, and capping materials (Kozma et al 2016 ; Thunugunta et al 2015 ; Narayanan et al 2011 ). GS can involve living organisms, such as bacteria (Joerger et al 2000 ) or fungi (Moghaddam et al 2015 ) and plants or natural extracts containing various biologically active compounds like polysaccharides, proteins, vitamins, or alkaloids.…”

Characterization of bio‐fabricated silver nanoparticles for distinct anti‐fungal activity against sugarcane phytopathogens

“…Peaks observed after FTIR analysis confirmed the presence of molecules that are previously reported to proceed the bio‐reduction of AgNO 3 ions to silver nanoparticles. Reduction of nanoparticles is probably due to the presence of capping material in all of three samples that is, fungal supernatant, bacterial supernatant, and the sugarcane husk extract (Thunugunta, Reddy, & Reddy, 2015). Among various electron microscopy techniques, SEM is a common and readily available surface imaging method through which morphology of nanoparticles can be probed to derive a histogram image by measuring and counting the size of nanoparticles.…”

Antibacterial activity of plant extract and zinc nanoparticles obtained from Syzigium aromaticum L.

“…Of these methods, the biological synthesis is to be comparatively widely used due to its advantages of being low cost, non-toxic and environmental friendly. Bioapplications of nanoparticles have paved way for green synthesis of nanoparticles [16]. The plant used in the present study was clove (Syzygium aromaticum) to obtain extracts with different solvent i.e., water and ethanol.…”