A novel plasma source for sterilization of living tissues

A source for the production of low-power plasmas at atmospheric pressure, to be used for the nondamaging sterilization of living tissues, is presented. The source, powered by radiofrequency and working with a helium flow, has a specific configuration, studied to prevent the formation of electric arcs dangerous for the living matter. It is capable of killing different types of bacteria with a decimal reduction time of 1–2 min; on the contrary, human cells such as conjunctival fibroblasts were found to be almost unharmed by the plasma. A high concentration of OH radicals, likely to be the origin of the sterilizing effect, is detected through their UV line emission. The UV and the OH radicals effect on the fibroblasts was analysed and no significant effects were detected