Reactive oxygen species-related plasma effects on the apoptosis of human bladder cancer cells in atmospheric pressure pulsed plasma jets

Helium/oxygen atmospheric pressure plasma jets driven by pulsed dc voltage with repetition rate of several tens of kilohertz are utilized for plasma-cell interactions. The effect of operating parameters on the apoptosis of cultured human bladder (EJ) cancer cells is investigated. The parameters such as applied voltage, pulse repetition frequency, and duty ratio determine the plasma dose. The apoptotic changes in cells with plasma treatment are detected by staining assay and flow cytometry. Apoptosis rates are observed to correlate well with both the plasma dose and the levels of intracellular and extracellular reactive oxygen species.