Particularly in dermatology and surgery,the use of CAP can benefit patients suffering from bacterial infection,impaired wound healing and chronic wounds [2].For example , it has been shown that the generated CAP has antibacterial effects that can work against antibiotic-resistant bacteria without harming the surrounding tissue.This includes methicillin-resistant Staphylococcus aureus (MRSA), the most common cause of hospital-acquired infections [3].Further studies have shown that cold plasma has the potential to improve wound healing by changing the gene expression of relevant key molecules [4].
Most of the research investigating the use of cold plasma in medicine can be divided into two major categories:direct plasma treatment and indirect plasma treatment [5].
In direct plasma treatment,the treated tissue assumes the function of one electrode ; thus,plasma is generated between the tissue surface and the plasma device electrode(dielectric-barrier ischarge; DBD).In indirect plasma treatment,the plasma is ignited inside a tube containing a flowing process gas—e.g. argon, helium or air—which carries active particles to the treated object.Such plasma devices are already in use—e.g. plasma torch,plasma jet, plasma needle,plasma pencil, etc.
In general,all kinds of cold plasma normally generate a mixture of different radical species,UV radiation,and a significant flux of charges, which can all influence biological functions when directly applied on tissue or cells. When operated with ambient air,cold plasma contains high amounts of reactive oxygens pecies(ROS), such as ozone(O3), superoxide(O2),and hydroxyl radicals (-OH), as well asreactive nitrogen species(RNS),such as nitric oxide(NO) and nitrogen dioxide (NO2) [6].