The application of engineered nanoparticles in food packaging, biosensors, cosmetics, waste treatment, and medicine harnasses unique physiochemical properties of nanoparticles in an effort to change environmental and biological effects. For example, the utility of the small size and metal ion leaching of nanoparticles as antibacterial agents can aid in combating antimicrobial resistance. In this study, copper nanoparticles were synthesized and surface stabilized with cetyltrimethylammonium bromide, ascorbic acid, or polyvinylpyrrolidone. The result was positively, negattively, and neutrally surface charged nanoparticles, respectively. We show that the antibacterial efficacy of the nanoparticles on Escherichia coli, Staphylococcus aureus, and Sphingobacterium multivorum is a combination of nanoparticle surface properties and exposure concentration. However, a more detailed analyses revealed that the the role of reactive oxygen species generation and release of metal cations are also critical nanoparticle attributes. Bacteria cells were exposed to the nanoparticles and reactive oxygen species and total metal ion content was measured. Results showed that the positively charged copper nanoparticles produced the highest concentration of reactive oxygen species in E. coli cultures, however, the same system produced the lower amount of free metal ion in the same culture systems. The interactions among all three particle systems and among all three bacterial cultures were analysed for statistical and biological significance via interaction and synergism plots. These results highlight the need for a mechanistic understanding of the role of reactive oxygen species and total metal ion content when developing nano-based antibacterial therapies. The findings herein will aid the design of safe exposure limits of nanotherapeutics for environmental health applications.

Mechanistic understanding of nanoparticle interactions with bacterial cells: Reaction oxygen species and metal ion content are equally important in nano-based antibacterial agents

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.