Effectiveness of surface dielectric barrier discharge (SDBD) with flow control for biological decontamination

Summary form only given. Nonthermal plasma generation by Dielectric Barrier Discharge (DBD) has gained increased interest in recent years, due to its easy ignition at atmospheric pressure and configurability into various geometries. The industrial, healthcare, water and air treatment, and surface modification sectors have been using this form of plasma generation for decades [1]. In this study we used a unique design of Surface Dielectric Barrier Discharge (SDBD), a type of DBD plasma generation method with electrodes placed asymmetrically on both sides of a dielectric material and electrodes enclosed on one side. SDBD plasma actuators have the ability not only to generate induced near-wall zero-net-mass-flux jet, which entrains the ambient gas, but also to propel the fluid entrained in the plasma region towards the surface being treated. Using this design, bacterial inactivation at varying exposure durations and distances was conducted. The tested bacterial strains included Escherichia coli, Salmonella, Listeria monocytogenes, Bacillus subtilis, and Bacillus cereus. A 3 to 4 log reduction was observed after 3 minutes of treatment. Scanning electron microscopy revealed significant damage to the cellular structure of Gram negative bacteria, while less damage but evident cytosolic leakage was observed with Gram positive bacteria. Optical emission spectroscopy revealed that no spectrum in the range of 200-290nm (UVC) was recorded, suggesting that UV radiation did not play a major role in cellular inactivation. The cell inactivation may be attributed to reactive species like OH and O, and also to the charged particles generated. The induced flow was also expected to play a role in cellular damage and transport of the short-lived species on to the treated surface. The uniquely designed SDBD has potential for clinical and industrial applications as a disinfectant for medical devices or food processing equipment.