Figure 4: Comparison of PDT effect between two photon excitation and one photon excitation on retinoblastoma cells. A. Y-79 cells were incubated or not (control) with 20 µg.mL-1 for 24 h with MSN-(1ɤPS)-Man or MSN-(2ɤPS)-Man, and then irradiated at 650 nm (30 min, 90 J.cm-2) or at 760 nm (3 × 1.25 s, 47 J.cm-2), respectively. Cell viability was quantified two days after. Statistically different *p < 0.05 from control (Student’s test). B. Irradiated zone showing photo-induced cell death.