Biosynthesis of silver nanoparticles using Ocimum sanctum (Tulsi) leaf extract and screening its antimicrobial activity

J Nanopart Res (2011) 13:29812988 DOI 10.1007/s11051-010-0193-y

RESEARCH PAPER

Biosynthesis of silver nanoparticles using Ocimum sanctum (Tulsi) leaf extract and screening its antimicrobial activity

Garima Singhal Riju Bhavesh

Kunal Kasariya Ashish Ranjan Sharma

Rajendra Pal Singh

Received: 9 June 2010 / Accepted: 20 December 2010 / Published online: 7 January 2011 Springer Science+Business Media B.V. 2011

Abstract Development of green nanotechnology is generating interest of researchers toward ecofriendly biosynthesis of nanoparticles. In this study, biosyn-thesis of stable silver nanoparticles was done using Tulsi (Ocimum sanctum) leaf extract. These biosynthesized nanoparticles were characterized with the help of UVvis spectrophotometer, Atomic Absorption Spectroscopy (AAS), Dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM). Stability of bioreduced silver nanoparticles was analyzed using UVvis absorption spectra, and their antimicrobial activity was screened against both gram-negative and gram-positive microorganisms. It was observed that O. sanctum leaf extract can reduce silver ions into silver nanoparticles within 8 min of reaction time. Thus, this method can be used for rapid and ecofriendly biosynthesis of stable silver nanoparticles of size range 430 nm possessing antimicrobial activity suggesting their possible application in medical industry.

Keywords Ocimum sanctum Silver nanoparticles

XRD AAS DLS FTIR TEM Antimicrobial

activity Nanomedicine

Introduction

Metal nanoparticles have a high specic surface area and a high fraction of surface atoms. Because of the unique physicochemical characteristics of nanoparticles, including catalytic activity, optical properties, electronic properties, antibacterial properties, and magnetic properties (Catauro et al. 2005; Crabtree et al. 2003; Krolikowska et al. 2003; Zhao and Stevens 1998), they are gaining the interest of scientist for their novel methods of synthesis. Silver is well known for possessing an inhibitory effect toward many bacterial strains and microorganisms commonly present in medical and industrial processes (Jiang et al. 2004). In medicines, silver and silver nanoparticles have a wide application including skin ointments and creams containing silver to prevent infection of burns and open wounds (Duran et al. 2005), medical devices and implants prepared with silver-impregnated polymers (Becker 1999; Silver 2003). In textile industry, silver-embedded fabrics are now used in sporting equipment (Klaus et al. 1999).

Nanoparticles can be synthesized using various approaches including chemical, physical, and biological. Although chemical method of synthesis requires

G. Singhal (&) R....