Bioactive Anti-Inflammatory and Antibacterial Plasma-Activated Air for Healing of Infected Wounds

Cold atmospheric plasmas are widely used in biomedicine. Although direct plasma treatments of wounds have been demonstrated, there are still obstacles hampering further clinical adoption, for example, the limited treatment area, inconsistent actions and risk of thermal injury. In this respect, plasma-activated air (PAA) is proposed and demonstrated for infected wounds treatment as an alternative to the conventional direct plasma treatment. The combination of gliding arc discharge reactor and dielectric barrier discharge reactor produces highly bioactive PAA. In in vitro sterilisation of Staphylococcus aureus, approximately 9-log reduction is achieved after the PAA treatment for 6 min. Bovine serum albumin is added to the S. aureus suspension to further simulate the wound exudate to accomplish inactivation of approximately 3-log reduction after 10 min. In vivo experiments show that the PAA treatment of infected wounds significantly reduces the bacterial load and improves the healing rate, revealing an optimal treatment time of 3 min/day. The immunohistochemical and blood biochemical analyses show that the PAA-3 min treatment enhances wound healing by inhibiting the tissue inflammatory response and inducing growth factor production without showing evident systemic toxicity. In conclusion, PAA holds great clinical promise as a safe and effective wound-healing strategy.