Fig. 5: In vitro radiotherapy.
a–e NO and/or O2-boosted radiotherapy. a, b Cell viabilities of a normoxic (21% O2) and b hypoxic (1% O2) U87MG cells subjected to different nanoparticle treatments, following by an X-ray irradiation at various doses (0, 2, 4, 6 Gy). In the groups with laser irradiation, the laser (808 nm) was applied after 24 h of incubation at a dosage of 1 W/cm2 for 3 min. n = 5 biologically independent samples per group. c Survival fraction determined by colony formation assays in both normoxic and hypoxic U87MG cells after different treatments. n = 3 biologically independent samples per group. d Fluorescent DNA-stained images by comet assays in hypoxic U87MG cells after different treatments. Scale bar, 50 μm. Experiments were performed three times with similar results. e Quantification of DNA damage (n = 6 independent experiments) according to the images in d. For c–e, groups g1–g8: g1, pHPFON-NO/O2 + Laser + X-ray; g2, pHPFON-NO + X-ray; g3, pHPFON-O2 + Laser + X-ray; g4, pHPFON + Laser + X-ray; g5, pHPFON + X-ray; g6, X-ray; g7, pHPFON-NO/O2 + Laser; g8, PBS. Laser (808 nm) was applied after 24 h of incubation with nanoparticles at 1 W/cm2 for 3 min. X-ray was applied after the laser irradiation at a dose of 4 Gy. f–i In vitro synergistic photothermal and radiotherapy. f MTT assays (n = 5 biologically independent samples). g Live and dead assays (n = 3 biologically independent samples, with similar results). Green, Calcein-AM, live cells. Red, ethidium homodimer-1 (Eth-1), dead cells. Scale bar, 100 µm. h Flow cytometry analysis (n = 2 independent experiments, with similar results). i Quantitative analysis according to h on cells after different treatments. For f–i, groups T1–T8: T1, pHPFON-NO/O2(++)(#); T2, pHPFON-NO/O2(++); T3, pHPFON-NO/O2(+)(#); T4, pHPFON-NO/O2(+); T5, (#); T6, (++); T7, pHPFON-NO/O2; and T8, PBS. (++) stands for 808-nm laser irradiation at 1 W/cm2 for 5 min. (+) stands for 808-nm laser irradiation at 1 W/cm2 for 3 min. (#) stands for a 4-Gy X-ray irradiation. Laser was applied after 24 h of incubation with nanoparticles and X-ray was applied after the laser irradiation, if applicable. Data are presented as mean ± s.d. Two-tailed Student’s t-test. *P < 0.05. **P < 0.01. ***P < 0.001. ****P < 0.0001.
