Biosynthesis of silver nanoparticle from leaf extract of Desmodium gangeticum (L.) DC. and its biomedical potential M. Thirunavoukkarasu ⇑ , U. Balaji, S. Behera, P.K. Panda, B.K. Mishra Bioresources Engineering Department, CSIR-Institute of Minerals & Materials Technology, Bhubaneswar, Orissa 751013, India highlights  Synthesis of stable AgNPs using leaves of Desmodium gangeticum was demonstrated.  The synthesized nanoparticles solution was stable for more than four months.  The AgNPs were spherical in shape with moderate variation in particle sizes.  The synthesized AgNPs exhibited antimicrobial activity due to synergistic effects. graphical abstract article info Article history: Received 26 February 2013 Received in revised form 12 July 2013 Accepted 21 July 2013 Available online 1 August 2013 Keywords: Desmodium ganeticum Silver nanoparticles UV-spectral analysis Antibacterial activity abstract An aqueous leaf extract of Desmodium gangeticum was employed to synthesize silver nano particles. Rapid formation of stable silver nanoparticles were observed on exposure of the aqueous leaf extract with solution of silver nitrate. The silver nanoparticles were characterized by UV–visible spectroscopy, scan- ning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR) UV–visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR). UV–visible spectrum of the aqueous medium peaked at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. SEM analysis revealed the spherical shape of the particles with sizes ranging from 18 to 39 nm and the EDAX spectrum confirmed the presence of silver along with other elements in the plant metabolite. Further, these biologically syn- thesized nanoparticles were found to be highly toxic against pathogenic bacteria Escherichia coli, thus implying significance of the present study in production of biomedical products. Ó 2013 Elsevier B.V. All rights reserved. Introduction Nanotechnology is a broad and interdisciplinary area of re- search and development that has been growing explosively world- wide in the past few years. Nature has devised various processes for the synthesis of nano and micro length scaled inorganic mate- rials which have contributed to the development of relatively new and largely unexplored area of research based on the biosynthesis of nanomaterials. Synthesis of nanoparticles using biological mate- rials is gaining impetus in recent years owing to their defined chemical, optical, photoelectro-chemical and electronic properties [1–4]. Among them, the metallic nanoparticles are most promising as they contain remarkable antibacterial properties due to their large surface area to volume ratio, which is of interest to research- ers due to the growing microbial resistance against metal ions, antibiotics, and development of resistant strains [5,6]. The synthe- sis and assembly of nanoparticles involving organisms ranging 1386-1425/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.saa.2013.07.033 ⇑ Corresponding author. Tel.: +91 6742379270. E-mail address: mtarasu@yahoo.com (M. Thirunavoukkarasu). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 116 (2013) 424–427 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa