Centre for Plasma Microbiology, Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom.
PLoS One. 2021 Mar 17;16(3):e0247589. doi: 10.1371/journal.pone.0247589. eCollection 2021.
Cold plasma generated in air at atmospheric pressure is an extremely effective antimicrobial agent, with proven efficacy against clinically relevant bacterial biofilms. The specific mode of bacterial inactivation is highly dependent upon the configuration of the plasma source used. In this study, the mode of microbial inactivation of a surface barrier discharge was investigated against Escherichia coli biofilms grown on polypropylene coupons. Different modes of exposure were considered and it was demonstrated that the long-lived reactive species created by the plasma are not solely responsible for the observed microbial inactivation. It was observed that a synergistic interaction occurs between the plasma generated long-lived reactive species and ultraviolet (UV) photons, acting to increase the antimicrobial efficacy of the approach by an order of magnitude. It is suggested that plasma generated UV is an important component for microbial inactivation when using a surface barrier discharge; however, it is not through the conventional pathway of direct DNA damage, rather through the synergistic interaction between liquid in the biofilm matrix and long-lived chemical species created by the discharge.
大气压下空气中产生的冷等离子体是一种极其有效的抗菌剂，已被证明对临床相关细菌生物膜具有疗效。细菌失活的特定模式高度依赖于所使用的等离子体源的配置。在这项研究中，针对在聚丙烯小片中生长的大肠杆菌生物膜，研究了表面阻挡放电的微生物失活动力模式。考虑了不同的暴露模式，并证明了等离子体产生的长寿命反应性物质并不是导致观察到的微生物失活的唯一原因。观察到等离子体产生的长寿命反应性物质与紫外线（UV）光子之间存在协同相互作用，使该方法的抗菌功效提高了一个数量级。当使用表面阻挡放电时，有人认为等离子体产生的 UV 是微生物失活的一个重要组成部分；然而，它不是通过直接 DNA 损伤的传统途径，而是通过生物膜基质中的液体与放电产生的长寿命化学物质之间的协同相互作用。
