A group of researchers from St Petersburg University has explored the effect that cold atmospheric plasma has on skin wounds. Oksana Ribalchenko, a professor at the University and the director of this project, which was completed last year with the support of a BRICS grant, spoke about what they discovered.

The project, The Bactericidal Effect and Regeneration of Skin Wounds under the Influence of Cold Atmospheric Plasmas, was a three-year-long joint effort of the University researchers and their counterparts from The Anhui University of Science and Technology in China. During the experiments, the researchers developed an apparatus that generated cold plasma, making it possible to vary the conditions for formation of plasma jets and then to compare the effectiveness of exposure to a plasma stream under a variety of compositions and speeds.

The project was completed last year. The researchers succeeded in establishing what the optimal conditions are for the generation of a plasma jet and what its most effective impact is on a special form of microbial community – bacterial biofilms. It is these biofilms that account for the development of infectious complications in wounds and hamper the regeneration of cells in tissues. When this happens, traditional anti-microbial agents have almost no effect, as opposed to the physical method of exposure to cold atmospheric plasma (CAP).

The findings of this study are presented in the article “Bactericidal Effect of a Dielectric Barrier Discharge Plasma Jet Generated in Laminar and Preturbulent Helium Flows” published in the journal Plasma Medicine and also in a collection of articles summarizing the results of the 28th Symposium on Plasma Physics and Technology.

Using what they had developed, the researchers became the first to examine the mechanisms behind the effect of exposure to cold atmospheric plasma on bacterial biofilms with a temperature of between 30–40 °С. The research was carried out on models of skin wounds in rats. Altering the speed of the plasma flow and the composition of its generating gas, the researchers established that a plasma flow composed of argon and helium is the most effective in healing skin wounds.

The researchers maintain that a uniform flow of cold plasma based on helium not only destroys bacterial cells but also averts the development of microbial communities in the form of biofilms, effectively accelerating the healing of infected wounds. The immediate effect of such plasma jets on the cells of the epidermis significantly stimulates the regeneration of lesional tissue. The bactericidal effect was most pronounced after six minutes of treating a wound.

The use of cold atmospheric plasma as a therapeutic practice calls for further investigation, but a marked bactericidal effect is only one of the obvious and scientifically proven results of this method.

Oksana Ribalchenko, Project Director and St Petersburg University professor

According to the professor, it has also been established that CAP has an adverse effect on tumour cells, which explains why around 70 percent of current research on cold plasma is devoted to developing devices for the treatment of oncological diseases.