Metal nanoparticles are nanosized entities with dimensions of 1-100 nm that are increasingly
in demand due to applications in diverse fields like electronics, sensing, environmental remediation,
oil recovery and drug delivery. Metal nanoparticles possess large surface energy and properties different
from bulk materials due to their small size, large surface area with free dangling bonds and higher
reactivity. High cost and pernicious effects associated with the chemical and physical methods of nanoparticle
synthesis are gradually paving the way for biological methods due to their eco-friendly nature.
Considering the vast potentiality of microbes and plants as sources, biological synthesis can
serve as a green technique for the synthesis of nanoparticles as an alternative to conventional methods.
A number of reviews are available on green synthesis of nanoparticles but few have focused on covering
the entire biological agents in this process. Therefore present paper describes the use of various
living organisms like bacteria, fungi, algae, bryophytes and tracheophytes in the biological synthesis
of metal nanoparticles, the mechanisms involved and the advantages associated therein.