A battery-operated atmospheric-pressure plasma wand for biomedical applications

In the past decade room-temperature atmospheric pressure plasma jets (RT-APPJs) have attracted a lot of attention due to their applications in the field of health care and medicine, including bacteria inactivation, blood coagulation, wound healing, teeth whitening, and tooth root canal treatment. To fulfill the specific requirements of various applications, many different types of RT-APPJs with different designs and driven by different power sources, including kHz AC, RF, microwave, pulsed DC and DC voltages, have been developed. On the other hand, external power sources (e.g., wall power or power generator) are needed for all these devices. In addition, most of these devices also need gas supply (e.g., He, Ar). Furthermore, for applications where bacteria, fungi, or viruses are hidden in narrow channels such as nasal cavity and ear canal, most of the currently available devices are not suitable for such situations. In this paper, a handheld, battery operated atmospheric pressure plasma rod (named plasma wand) which does not rely on external power source (e.g., wall power or power generator) and gas supply is reported. The plasma wand can be used for killing bacteria, fungi, or viruses that are hidden in narrow channels such as nasal cavity and ear canal, which are difficult to access using most of currently available devices. Besides, the electrical characterization, plasma wand temperature, emission spectra of the plasma, ozone and OH radical concentration generated by the device, are investigated by different diagnostic methods. The ozone concentration reaches 120 ppm at 1 mm away from the device and the OH concentration reaches 3.5×10¹⁴ cm^-3 in the plasma. The preliminary bacteria inactivation experiment results show that all bacteria samples on the microfiltration membrane are killed by this device within 30 s.