Bio inspired synthesis of monodispersed silver nano particles using Sapindus emarginatus pericarp extract – Study of antibacterial efficacy

Abstract The synthesis of silver nanoparticles employing aqueous extract obtained from the dried pericarp of “ Sapindus emarginatus ” is reported. Transmission electron microscopy divulges that the silver nanoparticles are not agglomerated and are moderately mono dispersed. Size of the particle ranges from 5 to 20 nm with an average particle size of 10 nm. Ultraviolet–visible spectra recorded show typical surface plasmon resonance (SPR) at 400 nm. X-ray diffraction analysis reveals the crystalline nature of the synthesized silver nanoparticles with face-centred cubic (FCC) geometry. Silver nanoparticles thus obtained demonstrated remarkable antibacterial activity against Bacillus subtilis , Staphylococcus aureus , Escherichia coli , Proteus mirabilis , Proteus vulgaris , Klebsiella pneumonia , Pseudomonas aeruginosa and Vibrio cholerae . Freshly prepared samples and sample containing 6 nm silver nanoparticles in particular exhibited enhanced activity against gram positive bacteria. The minimal inhibitory concentration was found to be in the range of 150–250 μg/mL.