%0 Journal Article
%T Microwave Assisted Biosynthesis of Silver Nanoparticles Using the Rhizome Extract of Alpinia galanga and Evaluation of Their Catalytic and Antimicrobial Activities
%A Siby Joseph
%A Beena Mathew
%J Journal of Nanoparticles
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/967802
%X Biomediated methods are considered to be a safer alternative to conventional physicochemical methods for the fabrication of nanomaterials due to their eco-friendly nature. In the present study, silver nanoparticles (AgNPs) were synthesized by microwave irradiation using aqueous rhizome extract of the medicinal plant Alpinia galanga. The nanoparticles were also synthesized under ambient condition without the assistance of microwave radiation and the former method was found to be much faster than the latter. The silver nanoparticles were characterized by UV-vis., FTIR, XRD, and HR-TEM analysis. UV-vis. spectroscopic studies provided ample evidences for the formation of nanoparticles. The FTIR spectrum confirmed the presence of plant phytochemicals as stabilizing agent around the AgNPs. XRD and HR-TEM analyses clearly proved the crystalline nature of the nanoparticles. From the TEM images, the nanoparticles were found to be roughly spherical in shape with an average diameter of 20.82 ¡À 1.8£¿nm. The nanoparticles showed outstanding catalytic activity for the reduction of methyl orange by NaBH4. The AgNPs were also evaluated for their antimicrobial activity by well diffusion method against S. aureus, B. subtilis, V. cholera, S. paratyphi, and A. niger. They were found to be highly toxic against all the tested pathogenic strains. 1. Introduction Nanomaterials have generated immense interest in recent times because of their promising applications in various areas of science and technology. Among these, metal nanoparticles are most capable owing to their properties that depend on their size and morphology which makes them a proper aspirant in various applications [1¨C4]. Several methods are available for nanoparticle synthesis such as chemical [5], photochemical [6], electrochemical [7], and biological methods [8]. Many of these production routes involve the use of toxic chemicals and require harsh reaction conditions. Chemical method of nanoparticle synthesis is still most common because of its short reaction time. However, in this method, the chemical reagents used as reducing and capping agent are usually toxic and lead to environmental pollution. With increasing focus on green chemistry, biological synthesis of metal nanoparticles is gaining more attention recently because of its simplicity, environment benign nature, and cost-effectiveness. Plant extracts and several microorganisms such as bacteria, fungi, and yeast have been used for nanosynthesis [9¨C11]. Many successful reports are obtainable on the biological synthesis of nanoparticles using plant extract
%U http://www.hindawi.com/journals/jnp/2014/967802/