Nanoscience has opened new vistas to manage phytopathogens, improve
crop productivity by the development of new varieties, and control infectious diseases
in humans. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) are highly
acclaimed for their wide potential application in various fields. Chemical and physical
methods of synthesis of AgNPs and AuNPs are widely used; however, such methods
possess numerous setbacks, such as the production of toxic residues and indispensable
need for high energy. Biosynthesis of nanoparticles is a cost-effective and
environmentally friendly method. A plethora of species of plant, bacteria, fungi, etc. is
available with potential biosynthesis ability. Fungi are a highly preferred organism
owing to the ability to secrete a large number of extracellular enzymes, metal toxicity
tolerance and bioaccumulation ability, and ease of handling of its biomass.
Extracellular enzymes act both as reducing as well as capping agents. Two different
methods are used by fungi for synthesis viz., intercellular and extracellular synthesis.
Extracellular synthesis is preferred over intercellular as it bypasses several down
streaming processes. During the reduction process, the metal ions (Ag2+ and Au3+) are
converted to an elemental state (Ag0
) which is in the nano range. Due to their
large surface-to-volume ratio and other properties, they become very effective against
other pathogens. There is an excellent prospect of the use of nanoparticles in the field
of agriculture and health and nanoparticles synthesized using a biological method
involving fungi could be a boon.