Disinfection of E. coli by nonthermal microplasma electrolysis in normal saline solution

We present a unique method to inactivate microorganisms in 0.9% NaCl solution (normal saline solution) by means of microplasmas. The device consists of a thin titanium wire covered by a glass tube for insulation except the tip and a ground electrode. Application of an asymmetric high-frequency, high voltage results in the formation of microbubbles at both electrodes. Repetitive light emission is observed in the vicinity of the powered electrode. We employed E. coli bacteria to investigate the disinfection efficiency of the device. More than 99.5% of E. coli were deactivated in 180 s. The survival curve showed biphasic behavior.