Figure 1

The plasma source and the experimental procedures used in this study. (a) Schematic drawing of the portable plasma source used in this study. The portable plasma source enabled operation in the corona and transient spark regime, as described under Methods^69,70,71. (b) Experimental procedures. A. Tumor cells were treated with CAP for varying times, combined with the addition of specific inhibitors/scavengers (INH) at defined time points. Apoptosis induction was quantified at different times. B. The same princples as shown under A were applied, except that medium was treated with CAP in the absence of cells, and was then transferred to the cells. C. Tumor cells were treated with CAP for 1 min, followed by 25 min incubation in the same medium. After a washing step, incubation was continued in fresh medium. The ¹O₂ scavenger histidine was present either before or after the washing step. Apoptosis induction was determined kinetically. D. Tumor cells were treated with CAP (or PAM) in the absence or presence of defined inhibitors/scavenger and incubated for 25 minutes in the same medium. After a washing step, the degree of inactivation of membrane-associated catalase was determined through a ONOO⁻ challenge and determination of ONOO⁻ mediated apoptosis induction¹². E. Tumor cells were treated with CAP for 1 min and incubated in the same medium for 25 min. After a washing step, further cultivation of the cells was performed in the absence or presence of defined inhibitors/scavengers (INHs) that allowed to define the molecular species involved in apoptosis-inducing signaling after catalase inactivation.