Cold sub-atmospheric and atmospheric pressure plasma for the treatment of Trichophyton rubrum onychomycosis: An in-vitro study

Previous studies have suggested the applicability of cold atmospheric pressure plasma for the treatment of onychomycosis. Whether delivering cold plasma in sub-atmospheric pressure would be beneficial for this purpose is yet to be established. The current study aimed to evaluate efficacy of cold sub-atmospheric and atmospheric pressure plasma in Trichophyton rubrum growth inhibition. Bovine nails infected with T. rubrum were treated by a cold air plasma device, which enables utilizing plasma in sub-atmospheric pressures (Low = 100 millibar; High = 300 millibar) or atmospheric pressure. The infected foci were exposed to the plasma source directly or indirectly. Treatment with high sub-atmospheric pressure setting achieved T. rubrum growth reduction of 94.0% and 73.0%, for direct and indirect exposure to the plasma source, respectively (P < .001). Low sub-atmospheric pressure setting achieved similar T. rubrum growth reduction of 86.2% for direct exposure to the plasma source (P < .001), but only marginally significant 58.8% reduction rate for indirect exposure to the plasma source (P = .056). None statistically significant fungal growth reduction was attained with the use of atmospheric pressure setting. Cold plasma was shown to effectively inhibit T. rubrum nail growth, with sub-atmospheric pressure setting achieving better outcome than atmospheric pressure.