Enhanced Antimicrobial Efficacy of Bimetallic Porous CuO Microspheres Decorated with Ag Nanoparticles

• Published in: ACS applied materials & interfaces Vol. 9; no. 45; pp. 39165 - 39173
• Main Authors: Chen, Xuemei, Ku, Seockmo, Weibel, Justin A., Ximenes, Eduardo, Liu, Xingya, Ladisch, Michael, Garimella, Suresh V.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15.11.2017
• Subjects: Anti-Bacterial Agents; Copper; Metal Nanoparticles; Microbial Sensitivity Tests; Microspheres; Porosity; porous CuO microspheres; bimetallic particles; antimicrobial mechanism; Ag nanoparticles; bacteria; antimicrobial efficacy
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b11364

The antimicrobial action of porous CuO microspheres (μCuO), Ag nanoparticles (nAg), and bimetallic porous CuO microspheres decorated with Ag nanoparticles (μCuO/nAg) was evaluated against surrogate microorganisms representative of pathogens commonly implicated in foodborne and healthcare-associated human infections. This work addressed the Gram-negative bacteria E. coli (Escherichia coli O157:H7-GFP B6-914), Salmonella (Salmonella enterica serovar enteritidis phage-type PT21), and the Gram-positive bacteria Listeria (Listeria innocua), as well as environmental microorganisms derived from local river water. Compared to particles composed only of CuO or Ag, the bimetallic porous μCuO/nAg particle exhibits enhanced antimicrobial efficacy. The antimicrobial action of bimetallic porous μCuO/nAg particles is dose-dependent, with 50 μg/mL particle concentration completely inhibiting the growth of both the Gram-negative (Salmonella) and the Gram-positive (Listeria) bacteria after 6 h. To assess the mechanism of antimicrobial action, the changes in surface morphologies of bacteria treated with the particles were observed using scanning electron microscopy. In the case of the Gram-negative bacteria, the bacterial cell membrane is damaged, likely due to the release of metal ions from the particles; however, particle-induced cell membrane damage is not observed for Gram-positive bacteria. Collectively, results from this work shed further light on possible mechanisms of antimicrobial action of micro-/nanoparticles and highlight the potential for bimetallic particle-based inhibition of microbial infections.