Accelerated healing of chronic wounds under a combinatorial therapeutic regimen based on cold atmospheric plasma jet using contact and noncontact styles

One critical element for applying atmospheric pressure plasma jet for medical purposes is that it is possible to construct a combinatorial therapeutic regimen based on contact and noncontact styles for the cold atmospheric plasma jet. This study evaluates plasma jet effectiveness for bacteria-infected wounds in a small animal model. In this investigation, we test a novel combinative treatment using contact and noncontact style for plasma jet that was generated at high voltage of ~ 9 kV. We use medical-grade argon gas as a single carrier gas. The object of plasma treatment is BALB/c mouse skin wounds that were infected with Staphylococcus aureus. We use four plasma jet treatments, namely, C (control), CP–CP (con-tact), NCP–NCP (noncontact), and CP–NCP (contact–noncontact). For CP–NCP, from days 0 to 7 we apply a contact style of plasma jet treatment to wounds to kill bacteria; from days 8 to 13, a noncontact style of plasma jet is applied to stimulate wound healing. Our results show that with CP–CP, contact plasma treatment can remove the biofilm layer, but after the biofilm layer disappears contact plasma treatment inhibits the wound-healing process. NCP–NCP is not effective in eliminating bacterial biofilms and impedes the wound-healing process. With CP–NCP, contact plasma exposure during days 0 to 7 is able to remove bacterial biofilms, and irradiation of noncontact plasma during days 8 to 14 accelerates wound healing. Finally, CP–NCP significantly accelerates healing. The combinatorial therapeutic regimen based on contact and noncontact styles of cold atmospheric plasma jet is recommended for chronic wound management, because it effectively removes bacterial biofilms and accelerates wound healing.