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Journal of Nanomaterials
Volume 2016, Article ID 9605906, 11 pages
Research Article

Antibacterial Activity of Partially Oxidized Ag/Au Nanoparticles against the Oral Pathogen Porphyromonas gingivalis W83

1Division of Biochemistry, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
2Northern Caribbean University, Manchester, Jamaica
3Division of Microbiology and Molecular Genetics, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
4Department of Earth and Biological Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
5College of Arts and Sciences, Faulkner University, Montgomery, AL 36109, USA

Received 24 September 2015; Accepted 26 January 2016

Academic Editor: Nay Ming Huang

Copyright © 2016 Megan S. Holden et al. This 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.


Advances in nanotechnology provide opportunities for the prevention and treatment of periodontal disease. While physicochemical properties of Ag containing nanoparticles (NPs) are known to influence the magnitude of their toxicity, it is thought that nanosilver can be made less toxic to eukaryotes by passivation of the NPs with a benign metal. Moreover, the addition of other noble metals to silver nanoparticles, in the alloy formulation, is known to alter the silver dissolution behavior. Thus, we synthesized glutathione capped Ag/Au alloy bimetallic nanoparticles (NPs) via the galvanic replacement reaction between maltose coated Ag NPs and chloroauric acid (HAuCl4) in 5% aqueous triblock F127 copolymer solution. We then compared the antibacterial activity of the Ag/Au NPs to pure Ag NPs on Porphyromonas gingivalis W83, a key pathogen in the development of periodontal disease. Only partially oxidized glutathione capped Ag and Ag/Au (Au : Ag ≈ 0.2) NPs inhibited the planktonic growth of P. gingivalis W83. This effect was enhanced in the presence of hydrogen peroxide, which simulates the oxidative stress environment in the periodontal pocket during chronic inflammation.