In last few years nanotechnology has received particular interest in a wide range of fields. The term “nano” comes from the Greek word “nano” meaning dwarf and denotes a measurement on the scale of one-billionth (10¬¬-9 ) of a metre in size. It is a branch of science, which deals with nano level substances. It widely covers the synthesis of materials (organic & in-organic) at neno scale and their application in various sectors like electronics, computers, sensing, solar energy, biomedical sciences, medicine, instrumentation etc. Synthesis of nanoparticles can be done by various approaches like physical and chemical, which covers several types of methods but these methods have drawbacks such as the use of toxic chemicals and the high-energy requirements of production. So an alternative way of synthesising metallic nanoparticles is by using biological approach for synthesis of nanoparticles is highly focused by scientific community. This includes the microbial synthesis and green synthesis. This review majorly provides the information about the biological sources, which could be used for synthesis of metallic nanoparticles. It could provide the better insight for the bio-assisted synthesis of metal nanoparticles.
