As we fast approach the post-antibiotic era, the urgency for novel antimicrobials and innovative strategies to combat resistance intensifies. Biofilms, which exhibit high antimicrobial tolerance and facilitate resistance gene transfer, are major contributors to antimicrobial resistance (AMR) and pose persistent challenges across healthcare, food safety, industry, and the environment. My research investigates plasma-activated water (PAW), an emerging technology that uses plasma, the fourth state of matter, to alter water’s physicochemical properties, producing antimicrobial reactive oxygen and nitrogen species (RONS). As a Postdoctoral researcher, I have demonstrated PAW’s effectiveness as an anti-biofilm alternative across multiple sectors.
This talk will focus on PAW’s biomedical applications, particularly in treating chronic wound infections, and its broader utility in decontaminating biofilm-contaminated stainless-steel surfaces, tools, and equipment, problematic across varying sectors. In an in vitro skin model using human keratinocytes, PAW pre-treatment significantly enhanced the efficacy of topical antiseptics, polyhexamethylene biguanide, povidone iodine, and MediHoney, against Escherichia coli biofilms. Mechanistically, PAW-derived RONS rapidly disrupt bacterial membranes, potentiating antiseptic action. In another key study, we evaluated how different input gases (e.g., air, nitrogen, argon, oxygen) affect PAW's efficacy. PAW generated with oxygen (PAW-oxygen) was most effective in eradicating E. coli biofilms on stainless-steel, linked to increased intracellular ROS. Superoxide anion radical was deemed a key ROS in PAW-oxygen with potent anti-biofilm activity. In a follow-up study, transcriptomic analysis of E. coli biofilms exposed to sub-lethal PAW-oxygen revealed a 40% shift in gene expression associated with several biological pathways like sulfur metabolism and oxidative phosphorylation. Knockout mutants of key upregulated genes (trxC, cysP, nuoM) showed reduced viability, highlighting superoxide’s role.
Overall, my Postdoctoral research highlights PAW's potential to target multiple microbial components, reducing opportunities for resistance. Using an interdisciplinary approach that bridges microbiology, engineering, and plasma physics, I present PAW as a transformative novel solution to tackling biofilms and AMR, with broad applications across multiple sectors.