Green Functional Nanomaterials: Synthesis and Applications

Abstract

Interaction between inorganic molecules and biological species is very fascinating. Green synthesis of metallic nanoparticle using plants and microorganisms is widely preferred over the physical and chemical methods due to their nontoxic, safer, biocompatible, less expensive, environment-friendly nature and greater biomedical applications. Some unicellular and multicellular organisms including plants and bacteria may be involved in biosynthesis as they have the ability to absorb and accumulate inorganic metallic ions. Advantages of using biological entities are that   nanoparticles of wide range of shapes, sizes, compositions and physical properties may be synthesized through this. In comparison between microorganisms and plants, approaches involving plants are more advantageous because of their faster and relatively easy scale up for production in large quantities. Biological synthesis of nanoparticles can be considered as a bottoms-up approach where such particles are formed by reduction or oxidation of metallic ions. Bacteria such as Escherichia coli, Lactobacillus spp., Pseudomonas sp. etc. can produce nanoparticles either by extracellular or intracellular processes. Parts of plants such as leaves, fruits, roots etc. can be used for synthesis of   nanoparticles due to the presence of phytochemicals which act as reducing and stabilizing agents and quantity, size and morphology of such products can be influenced by the concentration of plant extract, metal salt concentration, temperature, pH of the reaction solution and time of reaction. Biosynthesized nanoparticles have wide applications including cancer treatment, targeted drug delivery, fluorescent labelling, magnetic resonance imaging, in the field of biosensors, environmental remediation, gene therapy etc.