Characterization of a non-thermally operated electrosurgical argon plasma source by electron spin resonance spectroscopy

Non-thermal plasma treatment is one of the promising options for local anti-neoplastic treatment of dysplastic lesions and early intraepithelial cancer. Primarily, the antiproliferative properties are driven through the generation of reactive oxygen and nitrogen species. In this study, we investigated the amount and distribution of reactive species generated by a non-thermally operated electrosurgical argon plasma source using electron spin resonance (ESR) spectroscopy. During the plasma treatment of both, aqueous solution and solid human preputial tissue an increasing amount of different oxygen- and carbon-centered radicals was detected. However, and most probably due to spin trap degradation by the high energy input and the increase of reactive components in aqueous solution, the ESR signal decreased after treatment times exceeding 10 s.