FIG. 3.

Colony assays demonstrating the effects of antioxidants on E. coli survival during plasma treatment. (A) Effects of antioxidants on E. coli survival during plasma treatment in the presence of antioxidants (in PBS). The plasma settings were 500 Hz (3.12 J/cm²) for 24 s. The control was not treated with plasma. All other bars show 24 s of exposure in PBS or PBS with antioxidant. The numbers above the bars and preceded by an asterisk are the P values comparing the value to the value for plasma treatment (in PBS) without antioxidant (n = 3). (B) Exposure to antioxidants after plasma treatment does not protect E. coli cells from death, and the results show that plasma causes severe and nonrepairable damage to bacterial cells. The settings and parameters are the same as in panel A.