Fig 1.
Schematic illustration of the experimental setup used for this study.
Low-temperature atmospheric-pressure plasma was irradiated directly to cells in 200 μL of medium in the 24-well plate for 5 s and 10 s. The He gas flow rate used for the experiments was 3 L/min.
Table 1.
Primer sequence for real-time PCR.
Fig 2.
Effect of the plasma irradiation on the ALP activity of MC3T3-E1.
Cells were incubated for 7 days (A) or 14 days (B). The ALP activity is expressed as a relative value for which the value of the negative control (gray) is set to 1. Each value is the mean with SD (n = 5). ** p< 0.01 vs. control.
Fig 3.
Concentration of hydrogen peroxide generated by the plasma.
Each value is the mean with SD (n = 3).
Fig 4.
Effect of the H2O2 on the ALP activity of MC3T3-E1.
Cells were incubated for 14 days. The ALP activity is expressed as a relative value for which the value of the negative control (gray) is set to 1. Each value is the mean with SD (n = 5). **p < 0.01 vs. control.
Fig 5.
Effect of the plasma irradiation on the proliferation of MC3T3-E1.
Cells were incubated for 14 days. DNA was isolated and quantified to evaluate cell proliferation as a percentage of the negative control level (gray). Each value is the mean with SD (n = 5). ** p < 0.01 vs. control.
Fig 6.
Effect of the plasma irradiation on the mineralization of MC3T3-E1 cells.
Cells were incubated for 21 days. Plasma irradiation of cells was conducted in the first week (A) or in the first two weeks (B). Quantification of alizarin red is expressed as a relative value for which the value of the negative control (gray) is set to 1. Each value is the mean with SD (n = 5). **p < 0.01 vs. control.
Fig 7.
Plasma irradiation effects on MC3T3-E1 mRNA expression.
(A) Cells were incubated for 14 days. Plasma irradiation of cells was conducted for two weeks. (B) Cells were incubated for 21 days. Plasma irradiation of cells was conducted for the first two weeks. The mRNA expressions are expressed as a relative value for which the value of the negative control (gray) is set to 1. Each value is the mean with SD (n = 5). ** p< 0.01 vs. control.
Fig 8.
Effects of plasma irradiation for 0 s (a), 5 s (b), and 10 s (C) on ESR spectra of DMPO-OH and DMPO-H adducts obtained from pure water.
Fig 9.
Effects of plasma irradiation for 0 s (a), 5 s (b), and 10 s (C) on ESR spectra of CYPMPO-OOH and CYPMPO-OH adducts obtained from pure water.