Measurement of Reactive Species Produced by Discharge in Medium for Highly Efficient Gene Transfer*

There is a big demand of highly-efficient and minimally-invasive gene transfer technology. Conventional gene transfer methods have some problems such as low efficiency, high cytotoxicity, and high side-effect. Our research group has developed a gene transfer method using plasma in medium, which could potentially overcome the problems. However, most of the mechanism of the gene transfer using the discharge in medium remains unclear. Specifically, reactive species generated by the discharge in medium can be responsible for transfer efficiency and cell viability, but have not been investigated well. In this study, we have tried to quantify reactive species (H₂O₂, ^•OH, HOCl/OCl⁻) generated by discharge in Opti-MEM, a well-known serum-reduced media for gene transfer. As number of discharges (N) increased, H₂O₂ and ^•OH were significantly detected and produced with the total discharge duration, while the concentration of HOCl/OCl⁻ was not detected and was under the detection limit of 0.5 µM even at N = 10. This indicates that reactive oxygen species (ROS) can be predominantly generated compared to reactive chlorine species (RCS). In the presentation, chemical reactions induced after the discharge in Opti-MEM will be discussed.