Figure 6. Production of singlet oxygen and the hyperthermia effect of HIDPPNPs under NIR laser irradiation.
Upon exposure to an 808-nm laser with an intensity of 6 W/cm2, the production of singlet oxygen (A and B) and the variation in temperature (C and D) generated from the HIDPPNPs (A and C) and freely dissolved ICG (B and D) with concentrations of 0 (water only), 0.125, 0.25, 0.5, 1, 2, and 4 μM ICG equivalent were measured every 60 (for yield of singlet oxygen) or 30 (for variation of temperature) sec for 5 min. The quantity of singlet oxygen was analysed based on the intensity of SOSG-induced fluorescence, which was measured by using spectrofluorometry with excitation and emission wavelengths of 488 and 525 nm, respectively. The temperature at each time point was measured using a digital thermometer. The values are the mean ± s.d. (n = 3) in all examinations.