Real-Time Monitoring of Intracellular Chemical Changes in Response to Plasma Irradiation

摘要

Atmospheric pressure nonthermal plasma has shown great potential for medicine applications related to disease treatment. However, the microscopic interaction of the plasma particles and its associated fields with mammalian cells is still not well understood. Here, we present the first in situ observation of the fundamental processes related to the chemical changes inside live cells upon plasma irradiation, in real time. We analyze the effect of plasma dose on cell viability and on the internal chemical environment, using novel nano and molecular chemical sensors, in gliosarcoma cells. A pulsed nanosecond helium plasma jet was used as the plasma source. Our results show the accumulation of oxidative and nitrosative stress following two minutes of plasma irradiation, with the initiation of cell death only after three minutes of plasma irradiation. Moreover, the cell membrane integrity became compromised following six minutes of irradiation, which led to sudden changes in the intracellular chemical composition. We also present the first study involving the effects of plasma irradiation on lysosomes and the mitochondrial reduction potential. We observe that the intracellular accumulation of the ROS and RNS has negligible effects on the endosomal and lysosomal membrane integrity, suggesting that the cell membrane damage is likely caused by the external ROS and not by buildup of internal oxidative stress due to the irradiation. These observations illustrate the utility of nanoprobes and molecular probes in providing insight into the fundamental interaction of cold plasma with cells, thereby assisting in the interpretation of observed macroscopic effects of tissue exposed to plasma.