Molecular mechanism of bacterial outer membrane lysis through cold plasma reactive species evolution

Gram-negative bacteria, especially those with multidrug resistance, prevent the entry of antibacterial substances due to the presence of the outer membrane (OM). In response to such permeability issues, the development of novel antimicrobial technologies has focused on disrupting the bacterial OM of Gram-negative bacteria. Cold atmospheric plasma (CAP), as an emerging sterilization method, has shown promise in overcoming bacterial infection due to the reactive species generation. However, the molecular mechanisms underlying CAP-induced OM lysis remain largely unexplored. In this study, the relationship between OM components and CAP-induced bacterial lysis was investigated from the perspective of OM proteins and lipopolysaccharides (LPS). An integrated simulation and experimental approach, including biological effect, proteomics, plasma numerical simulation, and molecular simulation was utilized to elucidate the bacterial lysis induced by CAP through the destruction of the OM components mediated by the reactive species evolution. The reactive species produced by CAP caused the bacterial cell lysis by disrupting OM proteins and LPS, which was verified by molecular dynamics simulations. Notably, the bacteria resisting the lysis by regulating rescue pathways was mainly related to the fatty acid biosynthesis, LPS synthesis and transport, and OM proteins assembly. Additionally, CAP might disrupt the dense OM structure by attacking divalent metal ions used for bridging LPS molecules. Taken together, the findings shed light on the comprehensive molecular mechanisms of the interplay between CAP and OM, with potential implications for the development and engineering of CAP technologies.