Antibacterial Acrylamide Hydrogels Containing Silver Nanoparticles by Simultaneous Photoinduced Free Radical Polymerization and Electron Transfer Processes Mustafa Uygun, Muhammet U. Kahveci, Dilek Odaci, Suna Timur,* Yusuf Yagci* Introduction Polymeric materials containing metallic nanoparticles (NPs) have attracted tremendous scientific and technolo- gical interest in recent years due to their unique and versatile properties. [1–5] Research effort has been focused on the design and development of such materials containing noble metal NPs dispersed in a polymeric matrix, with potential applications in the field of optical, [6] electrical, [7] chemical, [8,9] biological, [10–12] and medical [13,14] devices as well as in data storage. [15] In particular, polymers with silver NPs (Ag NPs) have been identified as materials commonly used in biological and medical applica- tions. [10,16] In fact, the use of silver metal as a material to overcome infections, dates back as early as ancient times. [17] Important applications include employing Ag NPs as an antibacterial agent in dressing materials, medical devices, and equipments such as surgical gloves and covers coated with the antimicrobial polymers. [12,14] It is well- known that biological activity of silver, especially the antibacterial property, is size-dependent. [12] Thus, silver Full Paper M. Uygun, M. U. Kahveci, Y. Yagci Department of Chemistry, Faculty of Science and Letters, Istanbul Technical University, Maslak TR-34469, Istanbul, Turkey Fax: þ90 212 285 6386; E-mail: yusuf@itu.edu.tr D. Odaci, S. Timur Department of Biochemistry, Faculty of Science, Ege University, Bornova 35100, Izmir, Turkey E-mail: suna.timur@ege.edu.tr Ag-nanoparticle-containing hydrogels were successfully prepared by in situ reduction of silver nitrate in the presence of citrate molecules as stabilizing agent during photoinduced copolymerization of AAm and BAAm. Swelling-deswelling behavior and thermal properties of the synthesized hydrogels were investigated. The interior morphology of the gels exhibit continuity, which is a common feature for hydrogel net- works. Antimicrobial activities of the hydrogels were also investigated against pathogenic E. coli O157:H7, S. aureus, and non-pathogenic E. coli K- 12, which are model microorganisms for testing bactericidal properties. The hydrogels containing well-dispersed Ag NPs showed significant anti- bacterial activity. Macromol. Chem. Phys. 2009, 210, 1867–1875 ß 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/macp.200900296 1867