Overview on green synthesis of metallic nanoparticles

Nanotechnology provides an advance way to solve the modern problems in modern world. The newly evolving technologies, more sustainable products and processes help us to lead a more eco friendly life. As researchers realized that a substance's physico—chemical properties like chemical reactivity, electrical conductivity, diffusivity, melting point, optical and mechanical properties were affected by its size, the importance of these materials became clear. Metal nanoparticles that are produced by green routes are non toxic in nature, no harmful by products are produced during the synthesis process, also this route gives a higher yield of nanoparticles as compared to other conventional methods. The varied pytochemistry of different biological extracts contains diverse chemical components that affects the nanoparticles and enhance their chemical or physical properties. This review so far discusses the green synthesis of metallic nanoparticles, their properties, various possible reducing sources, reduction mechanisms of different phytochemicals and how they are involved in the reduction process of metal ions, various examples of metal nanoparticle synthesis, their safety and toxicity concerns, how these green synthesized nanoparticles could be used in various fields, how biodiversity affects the green synthesis and also the sustainability impact of green synthesis over the environment, making this review unique.