Biomolecular assisted synthesis and mechanism of silver and gold nanoparticles

Abstract

Gold (Au) and silver (Ag) nanoparticles (NPs) are useful nanomaterials. For these NPs various synthesis methods including chemical, physical and biological have been used. Biological methods have some advantages for the synthesis of Au and Ag NPs, such as the use of non-toxic chemicals, lower energy consumption, improved cost effectiveness and stable NP production. A large number of biological methods using culturable micro-organism, including bacteria, fungi and algae as well as plants have been explored as methodology for Au and Ag NP production. Since nanotechnology-based applications require the use of specified shape, size, surface charge and stability of NPs, a major problem associated with biologically synthesized Au and Ag NPs is that these NPs display variability in all these factors. This is a major drawback of biologically synthesized Au and Ag NPs compared to the physico-chemically synthesized NPs. Some organisms exhibit distinct metabolic pathways and produce biological macromolecules that enable them to withstand metal ions stress. Therefore, determining the molecular mechanics involved may enable the control of the shape, size, surface charge and stability of biologically synthesized Au and Ag NPs. This review article focuses on the biomolecular mechanism of Au and Ag NPs synthesis using different biological entities. A comprehensive study of these biomolecular mechanisms of Au and Ag NPs will be helpful for scientists and researchers for the fabrication of desired shape, size, surface charges and stability of Au and Ag NPs.