title: Green synthesis of highly stabilized nanocrystalline silver particles by a non-pathogenic and agriculturally important fungus T. asperellum.
abstract: A controlled and up-scalable biosynthetic route to nanocrystalline silver particles with well-defined morphology using cell-free aqueous filtrate of a non-pathogenic and commercially viable biocontrol agent Trichoderma asperellum is being reported for the first time. A transparent solution of the cell-free filtrate of Trichoderma asperellum containing 1 mM AgNO(3) turns progressively dark brown within 5 d of incubation at 25 °C. The kinetics of the reaction was studied using UV-vis spectroscopy. An intense surface plasmon resonance band at ∼410 nm in the UV-vis spectrum clearly reveals the formation of silver nanoparticles. The size of the silver particles using TEM and XRD studies is found to be in the range 13-18 nm. These nanoparticles are found to be highly stable and even after prolonged storage for over 6 months they do not show significant aggregation. A plausible mechanism behind the formation of silver nanoparticles and their stabilization via capping has been investigated using FTIR and surface-enhanced resonance Raman spectroscopy.
authors.affiliation: Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
authors.forename: P
authors.initials: P
authors.lastname: Mukherjee
authors.forename: M
authors.initials: M
authors.lastname: Roy
authors.forename: B P
authors.initials: BP
authors.lastname: Mandal
authors.forename: G K
authors.initials: GK
authors.lastname: Dey
authors.forename: P K
authors.initials: PK
authors.lastname: Mukherjee
authors.forename: J
authors.initials: J
authors.lastname: Ghatak
authors.forename: A K
authors.initials: AK
authors.lastname: Tyagi
authors.forename: S P
authors.initials: SP
authors.lastname: Kale