Plant-mediated biosynthesis of metallic nanoparticles: A review of literature, factors affecting synthesis, characterization techniques and applications

Nanoparticles exhibit unique properties that enable them to find potential applications in various fields. Accordingly, significant research attention is being given to the development of novel strategies for the synthesis of nanoparticles. Among these, biological route of nanoparticle synthesis has been portrayed as an efficient, low-cost and environmental friendly technique. Biological materials such as bacteria, fungi, yeast, algae and plant have been reported to possess high bioreduction ability to synthesize various size and shape of metallic nanoparticles. Of these biomaterials, this review focuses on plant-mediated biosynthesis of metallic nanoparticles. The biomolecules present in the plants such as terpenoids, flavones, ketones, aldehydes, proteins, amino acids, vitamins, alkaloids, tannins, phenolics, saponins, and polysaccharides play a vital role in reduction of metals. A systematic comparison of literature, based on the bioreduction capacity of various plant biomass/extract towards various metals under different experimental conditions, is also provided. Various instrumental techniques utilized to characterize nanoparticles are also discussed. Finally, this review also highlights the application of biosynthesized nanoparticles in different fields such as medicine, agriculture, catalytic, cosmetic and food. Thus, this article reviews the achievements and current status of plant-mediated biosynthesis, and hopes to provide insights into this exciting research frontier.