Plasma poration: Transdermal electric fields, conduction currents, and reactive species transport

Radical species and electric fields produced by gas plasmas are increasingly used in dermatology. Plasma-poration is the key basis for the efficient plasma skin treatment, which involves the plasma electric field, the directional motion of charged particles, and the transport of reactive particles. However, the enabling mechanisms of the plasma-poration remain unclear and require urgent attention. Here, the plasma-induced electric fields in each skin layer are accurately measured for the first time. The maximum electric field in the stratum corneum is 43 kV/cm, while the electric field in the active epidermis and dermis is about 1.8 kV/cm. This electric field strength is in the range of strength required for electroporation. Different from traditional electroporation treatments, the plasma-poration mainly relies on the effects of strong electric fields and the conductive current. The active power of the plasma-poration up to 18.5 kW/cm3 in the stratum corneum can rapidly change the structure of the skin. At the same time, reactive oxygen and nitrogen species also pass through the stratum corneum and effectively interact with the skin tissue. The plasma-poration does not cause any pain, which is an inevitable side effect of common electroporation.