Fig. 6
From: Photosensitizing deep-seated cancer cells with photoprotein-conjugated upconversion nanoparticles
Skin tissue-penetrating PDT using NIR-irradiated UCNP-KR-LP. a Representative confocal images of live/dead MCF-7 cells with SG/DAPI double staining after treatment with CS-UCNP-KR-LP. The cells were cultured under porcine skin tissues of different thicknesses (0−10 mm), and the images were obtained after light irradiation with a green laser (0.5 W/cm2 at 550 nm; top) or a NIR laser (1 W/cm2 at 980 nm; bottom). Blue, green, and red indicate DAPI, SG, and KR, respectively. Scale bar = 50 μm. b Quantitative FL analysis of SG intensity from confocal images in three independent experiments under similar conditions. c MTT assay of cell viability according to tissue thickness. MCF-7 cells were incubated with CS-UCNP-KR-LP (200 µg/mL), followed by green or NIR irradiation for 30 min. Error bars indicate the standard deviations from triplicate experiments. The significant difference in cell viability between green and NIR irradiation was evaluated (***P < 0.001, n = 3, paired t-test with Shapiro-Wilk test)