Atmospheric-pressure cold plasma jet for medical applications

An atmospheric-pressure plasma jet operated with air is presented. The plasma jet device is composed of a porous alumina dielectric element, an outer electrode, and a hollow inner electrode. Microdischarges in the porous alumina evolve to form a plasma jet that reaches lengths up to several tens of millimeters as the flow rate of the working gas increases. The discharge characteristics were investigated by measuring the voltage and current waveforms and by observing the optical emissions. Sterilization of Escherichia coli (E. coli) was carried out as an example for medical applications of the plasma jet. E. coli cells were completely removed after exposure to the air-plasma jet, even at an exposure time of less than 60 s.