부산대학교 도서관

In recent years, cold atmospheric plasma (CAP) has been extensively investigated for its potential as an alternative treatment in wound healing, dental cure, oncological therapy, and food processing. 1 Our group is developing an 8 element CAP array $(2.4 \mathrm{x}2 \text{cm})$ for biofilm inactivation and removal from surfaces. Hydrated Argon with a flow rate of 6 slm is used as the gas with the array operating at 2 kV rms and 20 kHz. The experimental setup consists of a motorized x-y stage used to hold and move the stainless-steel coupons containing the biofilm (Pseudomonas fluorescens) while the plasma array is fixed 1–4 mm above the coupons. We used a hydrated gas as previous analysis suggested, passing the gas mixtures through a Drechsel reservoir to humidify the feed gas to improve biofilm removal. A total of twelve stainless coupons $(\approx 20\ \text{mm}\ \mathrm{x}16\ \text{mm})$ were used for the experiment and were spaced uniformly across an area of 85 mm x 70 mm. Four coupons were treated under plasma, another four coupons were treated under gas flow only, and the rest of the coupons were used as the control. Each coupon was treated for a total plasma or gas exposure time of 90 seconds, except the controls. Colony forming units (CFU) were measured after the treatment. From the initial experiments, it was observed that the plasma treated coupons had a CFU reduction of $\sim80\%$ with a plasma to target gap of 4 mm and a plasma discharge current of $\approx 4.8\text{mA}$. Further optimization will include increased discharge current and optimization of the gas flow rates.