Reactive oxygen species and intracellular Ca2+ contribution to micro-discharge plasma gene transfection

Abstract

We investigated on the mechanism of plasma gene transfection. It is suggested that reactive oxygen species (ROS) directly or indirectly acts on endocytosis for gene transfection. The intracellular Ca2+ concentration was increased by plasma irradiation, and it was confirmed there is some kind of relationship between ROS and release of the intracellular Ca2+. It is clear that ROS are the most important chemical factors in plasma gene transfection and that Ca2+ is not a dominant factor but a subsidiary or consequential factor. Our studies also confirmed that the transfer mechanism for low molecular weight substances, such as YOYO-1, is different from the mechanism for molecules of higher weight, such as plasmid DNA. In the case of larger molecules, ROS play an important role by inducing endocytosis in plasma gene transfection. But in the case of smaller molecules, neither ROS nor ROS-dependent endocytosis is dominant. Some kind of “endocytosis-independent and ROS-free” transfer processes may exist for smaller molecules to be transferred into cells by plasm irradiation. To discuss the mechanism of micro-plasma gene transfection, it is important to note that the transfer mechanism is different for substances of different molecular sizes.