Bacteria inactivation using DBD plasma jet in atmospheric pressure argon

A coaxial dielectric barrier discharge plasma jet was designed, which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply, and an atmospheric pressure glow-like discharge was achieved. Two kinds of typical bacteria, i.e., the Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil), were employed to study the bacterial inactivation mechanism by means of the non-thermal plasma. The killing log value (KLV) of S. aureus reached up to 5.38 with a treatment time of 90 s and that of E. coil up to 5.36 with 60 s, respectively. According to the argon emission spectra of the plasma jet and the scanning electron microscope (SEM) images of the two bacteria before and after the plasma treatment, it is concluded that the reactive species in the argon plasma played a major role in the bacterial inactivation, while the heat, electric field and UV photons had little effect.