One step green synthesis and anti-microbial and anti-biofilm properties of Psidium guajava L. leaf extract-mediated silver nanoparticles

This paper describes a single-step green synthesis of extracellular silver nanoparticles (AgNPs) through an in-situ bio-reduction of aqueous solution of silver nitrate using Psidium guajava L UV-vis exhibits a characteristic surface plasmon resonance peak at around 487 nm. XRD analysis showed crystalline and face-centered cubic geometry of synthesized AgNPs. TEM results revealed stable and spherical particles with a mean diameter size of similar to 60 nm. Fourier transform infrared spectroscopy showed that the nanoparticles were capped with plant bioactive molecules. Phytosynthesized AgNPs showed broad-spectrum anti-microbial activity against Gram-positive, Gram-negative human pathogenic bacteria, and fungi. AgNPs showed prominent ability to inhibit the biofilms formed by Staphylococcus aureus, Escherichia coli and Candida albicans in a laboratory condition through crystal violet assay. The results suggest AgNPs as a promising candidate for the design of an effective antimicrobial and anti-biofilm agent in biomedical field. (C) 2014 Elsevier B.V. All rights reserved.