Research Article Synthesis, Characterization, and Antimicrobial Activity of Copper Oxide Nanoparticles Maqusood Ahamed, 1 Hisham A. Alhadlaq, 1,2 M. A. Majeed Khan, 1 Ponmurugan Karuppiah, 3 and Naif A. Al-Dhabi 3 1 King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2454, Riyadh 11451, Saudi Arabia 2 Department of Physics and Astronomy, King Saud University, Riyadh 11451, Saudi Arabia 3 Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia Correspondence should be addressed to Maqusood Ahamed; maqusood@gmail.com Received 16 July 2013; Revised 11 November 2013; Accepted 31 December 2013; Published 9 February 2014 Academic Editor: Do Kim Copyright © 2014 Maqusood Ahamed et al. 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. We studied the structural and antimicrobial properties of copper oxide nanoparticles (CuO NPs) synthesized by a very simple precipitation technique. Copper (II) acetate was used as a precursor and sodium hydroxide as a reducing agent. X-ray difraction patter (XRD) pattern showed the crystalline nature of CuO NPs. Field emission scanning electron microscope (FESEM) and feld emission transmission electron microscope (FETEM) demonstrated the morphology of CuO NPs. Te average diameter of CuO NPs calculated by TEM and XRD was around 23nm. Energy dispersive X-ray spectroscopy (EDS) spectrum and XRD pattern suggested that prepared CuO NPs were highly pure. CuO NPs showed excellent antimicrobial activity against various bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Enterococcus faecalis, Shigella fexneri, Salmonella typhimurium, Proteus vulgaris, and Staphylococcus aureus). Moreover, E. coli and E. faecalis exhibited the highest sensitivity to CuO NPs while K. pneumonia was the least sensitive. Possible mechanisms of antimicrobial activity of CuO NPs should be further investigated. 1. Introduction Metal oxide nanoparticles (NPs) have been receiving consid- erable attention for their potential applications in optoelec- tronics, nanodevices, nanoelectronics, nanosensors, infor- mation storage, and catalysis. Among various metal oxide NPs, CuO has attracted particular attention because it is the simplest member of the family of copper com- pounds and shows a range of useful physical properties such as high temperature superconductivity, electron cor- relation efects, and spin dynamics [1, 2]. CuO NPs are increasingly used in various applications such as in catal- ysis, batteries, gas sensors, heat transfer fuids, and solar energy [3]. CuO crystal structures possess a narrowband gap, giving useful photocatalytic and photovoltaic properties [4]. Microbial contamination of air, water, and soil due to diferent types of microorganisms creates problems in living conditions and is a serious issue in health care. Due to the spread of antibiotic resistant infections, interest in alternative antimicrobial agents, such as small antibiotics, cationic poly- mers, metal NPs, and antimicrobial peptides have been rising [5]. In this study, we reported synthesis, characterization, and antimicrobial activity of CuO NPs. CuO NPs were synthe- sized by a simple precipitation technique. Structural property of CuO NPs was examined by X-ray difraction (XRD), feld emission scanning electron microscopy (FESEM), and feld emission transmission electron microscopy (FETEM) equipped with energy dispersive X-ray spectroscopy (EDS). Antimicrobial activity of CuO NPs was examined by a well disk difusion assay and minimum inhibitory concentration (MIC) of CuO NPs against various bacterial strains. Hindawi Publishing Corporation Journal of Nanomaterials Volume 2014, Article ID 637858, 4 pages http://dx.doi.org/10.1155/2014/637858