Fig 1.
(a) Photograph of the plasma plumes from the jet array contacting a medium in a liquid container, and (b) the schematic of the experimental setup.
Fig 2.
(a) Gas temperature as a function of pulse width at two different gas flow rates (3 SLM and 5 SLM). (b) Measured gas temperature at each nozzle of the jet array as a function of the pulse width of applied voltage.
Fig 3.
(a) Typical optical emission spectrum from the jet array plasma. (b) The peak intensities of important lines (N2+, N2, OH, O, NO) as a function of the pulse width. (c) Excitation temperature was estimated based on Boltzmann plot at various pulse widths (1.8 ─ 5.5 μs). (d) The intensity ratios of two atomic lines He (587 nm)/He (706 nm) and O (777 nm)/He (706 nm) at several different pulse widths (1.8 ─ 5.5 μs).
Fig 4.
Ozone concentration as a function of pulse width: (a) in the gas phase, (b) in the PAM. Three different gas flow rates (3 SLM, 5 SLM, and 7 SLM) are considered.
Fig 5.
Nitrite concentrations in different media (DW, HBSS, and DMEM) immediately after the plasma exposure as a function of the pulse width of the applied voltage and plasma exposure time.
Here, the applied voltage Va = 7.5 kVpp, the gas flow rate 5 SLM, the plasma exposure time was 120 and 180 sec.
Fig 6.
Concentrations of H2O2 and NO3- produced in the plasma-treated media (DW, HBSS, and DMEM) at different conditions: (a) and (b) present the measured concentration of H2O2 and NO3- as functions of the applied voltage and the gas flow rate, respectively. (c) and (d) present the measured concentration of H2O2 and NO3- as a function of the treatment time at three different pulse widths (1.8, 2.7, and 5.5 μs), respectively. (e) and (f) present the dependence of [H2O2] and [NO3-] on the volume of media (DMEM + 10% FBS), respectively. In (e) and (f), [H2O2] and [NO3-] were measured as a function of media volume in the range from 3 ml to 6 ml. The grey bar represents the gas-only treated case.
Fig 7.
Plasma activated medium (PAM) induces apoptosis in human cervical cancer cells.
Cell viability measurement in HeLa cell lines at 24 h after PAM treatment. (A) Plasma conditions; the gas flow rate 5 SLM. Medium was exposed by plasma operated with the applied voltages at the pulse width of 2.7 μs for 0.5, 1, 2, and 3 minute. (B) Plasma conditions; the gas flow rate 5 SLM, applied voltage 7.5 kVpp, plasma exposure time 0.5, 1, 2, and 3 minute. (C) PAM induces apoptosis in HeLa cells. The percentage of the apoptotic cells was measured using the MUSE Cell Analyzer. Medium irradiated with plasma operated with the applied voltages at the pulse width of 2.7 μs was applied to HeLa cells for 24 hours. Bar graph indicated the quantitative analyses of each population. Data represent the mean ± S.D. of n = 3 samples; ***P<0.001.
Fig 8.
Plasma activated medium (PAM) induces mitochondrial depolarization through upregulating mitochondria ROS.
(A) Levels of mitochondrial superoxide was observed by DAPI and MitoSOX fluorescence using confocal microscopy. Representative fluorescence images show the staining of nuclei counterstained with DAPI (blue) and MitoSOX (red). HeLa cells were treated with PAM (pulse width 2.7 μs, incubation time 2 h). (B) Mitochondria potential was determined using the MUSE Cell Analyzer. Growth medium exposed to plasma was incubated with HeLa cells for 6 hours. Bar graph indicated the quantitative analyses of each population. (C) Western blotting analysis of Cytochrome C, phospho-JNK, JNK, phospho-p38 and p38 expression in HeLa cells treated with PAM (pulse width 2.7 μs, incubation time 2 h). Data represent the mean ± S.D. of n = 3 samples; ***P<0.001.