Hindawi Publishing Corporation Journal of Nanoparticles Volume 2013, Article ID 431218, 6 pages http://dx.doi.org/10.1155/2013/431218 Research Article Antibacterial Activity of Silver Nanoparticles Synthesized by Bark Extract of Syzygium cumini Ram Prasad and Vyshnava Satyanarayana Swamy Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Sector 125, Noida 201303, India Correspondence should be addressed to Ram Prasad; rprasad@amity.edu Received 31 January 2013; Revised 15 March 2013; Accepted 3 April 2013 Academic Editor: Amir Kajbafvala Copyright © 2013 R. Prasad and V. S. Swamy. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te unique property of the silver nanoparticles having the antimicrobial activity drags the major attention towards the present nanotechnology. Te environmentally nontoxic, ecofriendly, and cost-efective method that has been developed for the synthesis of silver nanoparticles using plant extracts creates the major research interest in the feld of nanobiotechnology. Te synthesized silver nanoparticles have been characterized by the UV-visible spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). Further, the antibacterial activity of silver nanoparticles was evaluated by well difusion method, and it was found that the biogenic silver nanoparticles have antibacterial activity against Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 27853), Azotobacter chroococcum WR 9, and Bacillus licheniformis (MTCC 9555). 1. Introduction Te broad spectrum of nanotechnology is important in the major felds of biology, chemistry, physics, and material sciences. Nanotechnology deals with the study of materials at the nanometers [1, 2]. Te day to day development of nanotechnology creates a major interest in the development and fabrications of diferent dimensioned nanoparticles [3]. Te nanomaterials can be synthesized by diferent methods including chemical, physical, irradiation, and biological methods. Te development of new chemical or physical methods has resulted in environmental contaminations, since the chemical procedures involved in the synthesis of nanoma- terials generate a large amount of hazardous byproducts [4]. Tus, there is a need for “green nanotechnology” that includes a clean, safe, ecofriendly, and environmentally nontoxic method of nanoparticle synthesis, and in this method there is no need to use high pressure, energy, temperature, and toxic chemicals [5, 6]. Te biological methods include synthesis of nanomaterial’s from the extracts of plant, bacterial, fungal species, and so forth. Te synthesis of nanoparticles from the plant extracts is considered to be a process [7]. Te prepa- ration and maintenance of fungal and bacterial cultures are time consuming and require aseptic conditions and large manual skills to maintain the cultures [8]. Plant extracts include bark, root, leaves, fruit, fowers, rhi- zoids, and latex and are used to synthesize the nanoparticles. Tese nanoparticles show diferent dimensions including the size, shape, and dispersion which have more efcacy than those synthesized from the chemical and physical procedures. Terefore, the use of green plants for similar nanoparticle biosynthesis methodologies is an exciting possibility which has compatibility for pharmaceutical and other biomedical applications, as they do not use toxic chemicals for the synthesis of nanoparticles [9, 10]. Nanoparticles had a wide variety of application in the major felds of medicine, electronics, therapeutics, and diag- nostic agents. Silver nanoparticles have wide application in biomedical science like treatment of burned patients, antimi- crobial activity and used the targeted drug delivery, and so forth [11]. Nowadays the nanoparticles are coated on the med- ical appliances, food covering sheets, and cans for storing the beverages and food [12–14]. However, there are many prob- lems and toxicity of using metal oxide nanoparticles on the human health. Use of plants for the synthesis of nanoparticles does not require high energy, temperatures, and it is easily