title: Potential cellular targets and antibacterial efficacy of atmospheric pressure non-thermal plasma.
abstract: Atmospheric pressure non-thermal plasma (APNTP) has been gaining increasing interest as a new alternative antibacterial approach. Although this approach has demonstrated promising antibacterial activity, its exact mechanism of action remains unclear. Mechanistic elucidation of the antimicrobial activity will facilitate development and rational optimisation of this approach for potential medical applications. In this study, the antibacterial efficacy of an in-house-built APNTP jet was evaluated alongside an investigation of the interactions between APNTP and major cellular components in order to identify the potential cellular targets involved in plasma-mediated bacterial destruction mechanisms. The investigated plasma jet exhibited excellent, rapid antibacterial activity against a selected panel of clinically significant bacterial species including Bacillus cereus, meticillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa, all of which were completely inactivated within 2 min of plasma exposure. Plasma-mediated damaging effects were observed, to varying degrees, on all of the investigated cellular components including DNA, a model protein enzyme, and lipid membrane integrity and permeability. The antibacterial efficacy of APNTP appears to involve a multiple-target mechanism, which potentially reduces the likelihood of emergence of microbial resistance towards this promising antimicrobial approach. However, cellular membrane damage and resulting permeability perturbation was found to be the most likely rate-determining step in this mechanism.
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK; Faculty of Pharmacy, University of Jordan, Amman 11942, Jordan.
authors.forename: Mahmoud Y
authors.initials: MY
authors.lastname: Alkawareek
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Gorman
authors.affiliation: Centre for Plasma Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
authors.forename: William G
authors.initials: WG
authors.lastname: Graham
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK. Electronic address: b.gilmore@qub.ac.uk.
authors.forename: Brendan F
authors.initials: BF
authors.lastname: Gilmore
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001274:Atmospheric Pressure; D004247:DNA; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D058626:Plasma Gases / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D058626:Plasma Gases; D004247:DNA
keywords: Atmospheric pressure plasma; Cold atmospheric plasma; Destruction mechanism; Non-thermal plasma; Plasma medicine; Plasma sterilisation