A Two-Mode Portable Atmospheric Pressure Air Plasma Jet Device for Biomedical Applications

In this paper, a low-cost and portable plasma device is developed to generate atmospheric pressure nonthermal air plasma jet for safe and effective biomedical applications. The device mainly consists of a pen electrode, a high-frequency ac power supply, an ac/dc module, and a dc air pump, and it totally costs only U.S. $63 and has a small size of 280 mm ×190 mm × 180 mm. The appearance of two-mode discharge of half-wave and full-wave breakdown with the changing of applied voltage is identified, and the length of the plasma jet is optimized through studying on the influences of distance between two electrodes, gas flow rates, and hole diameters of the gas outflow in ground electrode. Stronger plasma with a longer jet length of 12 mm can be obtained in the full-wave breakdown discharge mode, while moderate plasma with a length of 8 mm can be obtained in the half-wave breakdown discharge mode. The discharge characteristics of the device such as the main generated active particle, voltage and current, discharge power, and operation temperature are obtained. It is shown that rich active species for biomedical application can be generated at low power of approximate 2 W and low operation temperature of approximate 40 °C. The developed device is tested for biomedical application, and the results of effective sterilization of C. albicans and blood coagulation are obtained.