"Spicy world of NanoScience" since 2007
R.S. Subhasree, Prasanna S. Bakshi, D. Selvakumar* N.S. Kumar and V.C. Padaki
Defence Bioengineering and Electromedical Laboratory (DRDO), Bangalore
Metal nanoparticles are explored in recent years as an alternative approach to effectively kill drug resistant pathogenic microorganisms. Silver nanoparticles are the metal of choice for antibiotic resistant microbes. Synthesis of silver nanoparticles through biological route is preferred over chemical route to promote green chemistry. In the present study, we report an ultra low cost, eco-friendly method for synthesis of silver nanoparticles using an aqueous extract of Trigonella foenum-graecum (Fenugreek). The reduction of Ag+ from silver nitrate (precursor) to nano silver was achieved through polyphenols and quercetin present in Trigonella. The reduction was confirmed by UV-visible spectroscopy showing surface plasmon resonance of silver nanoparticles at 458 nm. The minimum inhibitory concentration for the synthesized nanoparticles was found out to be 450 μg/mL against E. coli and S. aureus. The as prepared nanoparticles were used to enhance the bactericidal effects of chitosan biopolymer. The nanosilver incorporated chitosan (1% w/v) was cross linked using glutaraldehyde (1% w/w) and prepared as free standing films. The films were also characterized by FT-IR and SEM. The membranes were found to be permeable to water vapor and the nanocomposites swelled up to 1600 % in water. In antimicrobial studies, the chitosan – silver bionanocomposite showed 99.99% reduction against E. coli and S. aureus within an hour. It is proposed to use this bionanocomposite in applications of wound healing due to its excellent swelling and antimicrobial properties.