1Material Science Laboratory, Department of Physics, Sibsagar College, Joysagar 785665, Assam, India
2Centre for Nanoscience and Composite Materials, Deptt. of Chemistry, Dibrugarh University, Dibrugarh 786004, India
3Department of Zoology, J.B.College, Jorhat, Assam 785001, India
4Department of Biotechnology , J.B.College, Jorhat, Assam 785001, India
5Department of Physics, J.B.College, Jorhat, Assam 785001, India
Adv. Mater. Lett., 2015, 6 (3), pp 260-264
Publication Date (Web): Feb 22, 2015
Copyright © IAAM-VBRI Press
Silver nanoparticles of average sizes ~18-21 nm in diameter were prepared by a green approach via chemical reduction of silver nitrate (AgNO3) using Asiatic Pennywort and Bryophyllum leaf extracts as reducing and capping agents. The bio-reduced silver nanoparticles were characterized by UV-Vis spectroscopic, XRD and TEM techniques. The characteristic surface plasmon band of colloidal solutions of AgNPs synthesized from Asiatic Pennywort and Bryophyllum leaf extracts were found at 445 nm and 405 nm respectively. The results of XRD and SAED pattern showed that the biosynthesized AgNPs have a crystalline structure with cubic phase (fcc). The antimicrobial activities of the as synthesized AgNPs were investigated against gram negative bacteria Pseudomonas Fluorescens and gram positive bacteria Staphylococcus Epidermidis. It was observed that silver nanoparticles obtained from Asiatic Pennywort was more effective on gram positive bacteria Staphylococcus Epidermidis while AgNPs obtained from Bryophyllum was more effective on gram negative bacteria Pseudomonas Fluorescens indicating size dependent activity of AgNPs.
Green synthesis, silver nanoparticles, plasmon resonance band, antimicrobial activity.