ConclusionsThe efficacy and mechanistic insights of an emerging alterna-tive antimicrobial approach have been investigated in this study.An in-house-built APNTP jet was shown to be capable of com-plete eradication of all the tested bacterial species in just 2 minof exposure. Although the XTT assay showed relatively higher cellviability than predicted by the colony count method at shorterplasma exposures, the two methods were in good agreementat longer exposures, confirming the excellent antibacterial activ-ity of APNTP. Effects of plasma exposure on the major bacterialcell components were also investigated in this study. Althoughit seems that membrane damage through lipid peroxidation ismost likely the primary factor in plasma-mediated bacterial celldeath, other cellular components including DNA and proteinaceousenzymes were also damaged. Although plasmid DNA and pro-teinase K were exposed in their ‘isolated forms’ in this study andhence further evaluation in situ might be required in the futurefor a better understanding of the exact kinetics of their damagein a cellular environment, this study confirms that APNTP medi-ates a non-selective, multiple-target mechanism of action, makingthe emergence of microbial resistance towards such an approachunlikely. Further elucidation of the plasma-mediated bacterial celldestruction mechanism is a crucial topic for future research, withemphasis on an improved understanding of the effects on cell com-ponents as well as a better identification of the activity-responsibleplasma-generated reactive species. This will ultimately allow formore guided development and application-directed optimisationof this promising approach