Synergetic effects of atmospheric plasma and UVA treatment for eye infection pathogens disinfection

We report a combined method of using atmospheric surface micro-discharge (SMD) with UVA exposure to provide a fast and efficient method against eye infection pathogens. 4 kinds of typical eye infection bacteria were chosen and treated under SMD treatment only, UVA exposure only and 5min SMD treatment followed by 1 or 2 min UVA exposure in buffered solution. The combination of plasma treatment and UVA exposure presented the best antibacterial effect, especially for the UV-resistant bacteria strain, Serratia marcescens. This synergetic method has been found to have no selectivity on bacterium type. The possible mechanism of the synergetic effects was preliminarily proved to be caused mainly by photodecomposition of nitrite. UVA photolysis analysis of pure nitrite, H
2
O
2
solution and their mixture indicated the formation of peroxynitrite in buffered solution partly contributed to the anti-bacterial effect in this work.