Green synthesis, characterization and antimicrobial activity of Au NPs using Euphorbia hirta L. leaf extract

The activity of a nano sized particle is said to be greater when compared to that of its parent materials combined. Thus, an attempt was made to produce gold nanostructures having unusual physicochemical properties. In this study, eco-friendly, non-toxic gold nanoparticles (Au NPs) were biologically synthesized using the leaf extract of Euphorbia hirta L. The synthesis of Au NPs was confirmed by a change in extract color from pale yellow to purple and surface plasmon resonance spectra obtained in a range of approximately 530 nm. Nanoparticles whose sizes ranged from 6 nm to 71 nm, were synthesized. Different instrumental techniques were used to characterize the synthesized AuNPs, such TEM, XRD, EDAX, AFM, particle size analyzer, FTIR and Raman spectra. Also the antibacterial activity of the green synthesized Au NPs against bacterial strains of Escherchia coil, Pseudomonas aeroginosa and Klebsiella pneumonia was studied using MIC method, and found to be highly effective. (C) 2013 Elsevier B.V. All rights reserved.