Figure 1.

NTAP dose-dependent cytotoxicity of HeLa and GBM cells. (A) Schematic of the DBD-NTAP set-up used in this study, and a photograph showing plasma generation which fluoresces in the presence of helium gas. (B) Both U373MG cells and HeLa cells were exposed to NTAP at 75 kV for up to 5 min. Forty-eight hours later, the cells were analysed using the Alamar Blue cell viability assay. All experiments were repeated a minimum of three times. Statistical analysis was carried out using non-linear regression analyses. (C) Both U373MG cells and HeLa cells were exposed to NTAP at 75 kV for up to 180 s. HeLa cells were trypsinised and counted using a haemocytometer 48 h post treatment. U373MG cells were analysed 96 h post treatment. All experiments were repeated a minimum of three times. Statistical analysis was carried out using non-linear regression analyses. (D) HeLa and U373MG cells were exposed to NTAP at 75 kV for 3 min. After a 48-h incubation period, cells were loaded with 1 μg ml⁻¹ JC-1 dye and analysed by flow cytometry. Data shown depict apoptosis measured by quantitative shifts in the ΔΨm (red to green) fluorescence intensity ratio before and after H₂O₂ and NTAP expsoure. All experiments were repeated in triplicate. Statistical analysis was carried out using one-way ANOVA with Tukey's multiple comparison post-test (*P<0.05). A full colour version of this figure is available at the British Journal of Cancer journal online.