RESUMO
Cold atmospheric pressure plasma (CAP) has been shown to kill bacteria and remove biofilms. Here we report the development of a unique CAP array device consisting of a parallel stack of eight linear-discharge plasma elements that create a ~ 5 cm2 (2.4 cm × 2 cm) treatment area. The CAP device is fabricated from Low Temperature Co-fired Ceramic (LTCC) layers to create 24 mm long linear-discharge channels (500 µm gap) with embedded opposing silver metal electrodes. A 20 kHz AC voltage (0.5-5 kV) applied to the electrodes generates an Ar/O2 plasma between the plates, with the gas flow directing the reactive species toward the biological sample (biofilms, etc.) to affect the antimicrobial treatment. External ballast resistors were used to study discharge uniformity in the stacked array elements and internal thick film ballast resistors (≈150 kΩ) were developed to create a fully integrated device. Typical element discharge currents were 1-2.5 mA with the total array current tested at 20 mA to provide optimal device uniformity. The plasma discharge was further shown to produce reactive hydrogen peroxide and exert antimicrobial effects on Pseudomonas biofilms and Salmonella contaminated eggshell samples, with >99% of the bacterial cells killed with less than 60 seconds of plasma exposure.
RESUMO
A cold atmospheric pressure plasma device was developed using two parallel plates of Low Temperature Co-fired Ceramic with embedded electrodes. The 2.4 cm wide by 1 mm deep plasma discharge operates at 20 kHz with a 2-5 kV AC drive signal across a 0.25 mm gap. Mixed Argon/oxygen plasmas were directed between the plates to flow toward a bacterial biofilm sample for treatment. Results showed that at 4-5 kV the plasma etched away a bacterial biofilm on glass in 10 minutes. In addition, we showed that short plasma treatments rapidly killed biofilm resident bacteria with ED90 values of <15 s.
