title: Biosynthesis, structural characterization and antimicrobial activity of gold and silver nanoparticles.
abstract: An eco friendly simple biosynthetic route was used for the preparation of monodisperse and highly crystalline gold and silver nanoparticles using cell free extract of fungus, Candida albicans. Transmission electron microscopic studies show the formation of gold and silver nanocrystals of average size of 5 nm and 30 nm with the specific surface areas of 18.9 m(2)/g and 184.4 m(2)/g respectively. The interaction of gold and silver nanoparticles with proteins has been formulated by FT-IR spectroscopy and thermal gravimetric analysis. The formation of gold and silver nanoparticles was also confirmed by the appearance of a surface plasmon band at 540 nm and 450 nm respectively. The antimicrobial activity of the synthesized gold and silver nanoparticles was investigated against both Staphylococcus aureus and Escherichia coli. The results suggest that these nanoparticles can be used as effective growth inhibitors against the test microorganisms. Greater bactericidal activity was observed for silver nanoparticles. The E. coli, a gram negative bacterium was found to be more susceptible to gold and silver nanoparticles than the S. aureus, a gram positive bacterium.
authors.affiliation: Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India. tahmad3@jmi.ac.in
authors.forename: Tokeer
authors.initials: T
authors.lastname: Ahmad
authors.forename: Irshad A
authors.initials: IA
authors.lastname: Wani
authors.forename: Nikhat
authors.initials: N
authors.lastname: Manzoor
authors.forename: Jahangeer
authors.initials: J
authors.lastname: Ahmed
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Asiri
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D004058:Diffusion; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D006046:Gold / Q000737:chemistry / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D010316:Particle Size; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013499:Surface Properties; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D000890:Anti-Infective Agents; D012834:Silver; D006046:Gold