Fabrication and Performance of a Multidischarge Cold-Atmospheric Pressure Plasma Array

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 sim 5 -cm {mathbf {2}} (2.4 cm times 2 cm) treatment area. The CAP device is fabricated from low-temperature cofired ceramic (LTCC) layers to create 24-mm-long linear-discharge channels (500- mu text{m} gap) with embedded opposing silver metal electrodes. A 20-kHz ac voltage (0.5-5 kV) applied to the electrodes generates an Ar/ text{O}-{mathbf {2}} plasma between the plates, with the gas flow directing the reactive species toward the biological sample (biofilms and so on) 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 ( approx 150~text{k}Omega ) 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 s of plasma exposure.