Investigating the impact of Radical Generated in Water Samples Exposed to DBD Plasma for Medical Applications*

In this study, we investigated the phenomenon of plasma-water interaction. Dielectric barrier discharge (DBD) plasma has medical applications such as wound healing and sterilization. Research indicates that plasma contains reactive oxygen and nitrogen species that interact with wounds in a complex manner to accelerate healing. One method involves exposing the wound to the DBD plasma, facilitating various chemical interactions, though healing rates depend on wound conditions. Another approach involves producing plasma-activated water (PAW) separately to treat wounds to expedite bacterial mitigation and thereby enhance healing. Therefore, it is crucial to examine bacterial responses under different incident plasma conditions. The wound healing process can be further characterized by analyzing various radical concentrations (NO2-,NO3-,H2O2) generated in PAW. In our study, we examined the impact of PAW on bacteria elimination (E. coli) by comparing colonies in PAW-treated and control samples. It was found that colony reduction strongly correlates with exposure time and plasma power; notably, a 75% reduction was observed with a 10-15 second plasma exposure. Additionally, absorption spectroscopy was conducted on PAW samples to assess changes in absorbance as a function of exposure time, revealing strong dependencies on plasma operating conditions. Future research will focus on determining absolute concentrations of NO2-, NO3-, H2O2 through calibration curves using reference samples.