M. Wang, M. Gao, T.J. Webster
Massachusetts Institute of Technology,
United States
Keywords: biofilms, computational modeling, bacteria
Summary:
Given the potential to interact with live cells and tissues due to low ion temperature and multiple components (such as reactive oxygen/nitrogen species (RO/NS), electrons, and ultraviolet (UV) light), cold atmospheric plasma (CAP) was tested for antibacterial purposes in this study. The experimental results indicated that both Gram-positive and Gram-negative bacteria could be inactivated with CAP treatment. The deduction after 3 min CAP treatment against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) was 83.4% and 80%, respectively, which was less susceptible compared to Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) (more than 95%). An established mammalian/bacteria membrane with RO/NS model revealed dynamic nanopore formation on the bacteria membrane due to the existence of RO/NS. Nanopores induced by RO/NS further led to bacterial content leakage and death. This modeling result provided a new atomscopic and nanoscopic explanation of how CAP treatment influenced bacterial membranes leading to their death which exhibited good agreement with the experimental results of altered bacterial morphology and leakage. Additionally, experiments demonstrated the removal of a pre-formed biofilm after CAP treatment, indicating that CAP has a positive effect on biofilm removal in situ which deserved further attention. Meanwhile, results from this study showed that CAP treatment under same condition had no significant toxic to fibroblast cells. Overall, these findings are critical for the successful development of CAP for numerous antibacterial applications.