Influence of pulse characteristics and power density on stratum corneum permeabilization by dielectric barrier discharge.

Background: In recent years, the medical use of cold atmospheric plasma has received much attention. Plasma sources can be suited for widely different indications depending on their physical and chemical characteristics. Being interested in the enhancement of drug transport across the skin by plasma treatment, we evaluated three dielectric barrier discharges (DBDs) as to their potential use in permeabilizing human isolated stratum corneum (SC).

Methods: Imaging techniques (electrochemical and redox-chemical imaging, fluorescence microscopy), transepithelial electrical resistance measurements and permeation studies were employed to study the permeabilizing effect of different DBD-treatments on SC.

Results: Filamentous μs-pulsed DBDs induced robust pore formation in SC. Increasing the power of the μs-pulsed DBD lead to more pronounced pore formation but might increase the risk of undesired side-effects. Plasma permeabilization was much smaller for the ns-pulsed DBD, which left SC samples largely intact.

Conclusions: The comparison of different DBDs provided insight into the mechanism of DBD-induced SC permeabilization. It also illustrated the need to tailor electrical characteristics of a DBD to optimize it for a particular treatment modality. For future applications in drug delivery it would be beneficial to monitor the permeabilization during a plasma treatment.

General Significance: Our results provide mechanistic insight into the potential of an emerging interdisciplinary technology - plasma medicine - as a prospective tool or treatment option. While it might become a safe and pain-free method to enhance skin permeation of drug substances, this is also a mechanism to keep in mind when tailoring plasma sources for other uses.