Cold atmospheric plasma therapy with optimized O₂–H₂ gas mixture for enhanced antimicrobial applications in wound care

Cold atmospheric plasma (CAP) therapy has emerged as a significant topic in biomedical research for infection treatment and tissue healing. This study focuses on the development and optimization of a dielectric barrier discharge (DBD) micro-jet system using an oxygen–hydrogen (O2 – H2) gas mixture. The aim of this study was to secure high antimicrobial efficacy with cold operation stability for topical wound care. Systematically, the optimal plasma conditions were adjusted by changing the gas ratio, input power, flow rate, and treatment time. The 4:1 O2 – H2 gas mixture was the best compromise between reactivity, concentration, and thermal safety. The quantification of H2O2 and ·OH radicals at 450 ± 25 µM and 0.84 ± 0.08 relative units (RU), alongside the detection of atomic oxygen (O I) at 777 nm, inactivated Escherichia coli and Lactobacillus casei at approximately 180 and 240 s, respectively, across all samples. The temperature at the 5 mm-referring distance remained below 30◦C, showing non-thermal behavior. The construct maintained highly consistent discharge/recharge behavior and long-term cycle stability. Compared to a conventional argon plasma system, the new configuration led to cost savings in terms of operation by at least 80% and achieved improved biofilm penetration. These in vitro results suggest that plasma can be a potential cost-effective platform for disinfecting chronic wounds, with implications for the development of portable clinical devices.