The photodynamic property of PHSA-ICG-TAT was evaluated by determining the generation of 1O2 according to the fluorescence signal of Singlet Oxygen Sensor Green (SOSG). SOSG was added to different solutions of ICG (5 μM), PHSA-ICG-TAT, and PHSA-ICG (PHSA-ICG and PHSA-ICG-TAT containing ICG equivalent to 5 μM) in PBS and irradiated with an 808 nm laser (power density: 2.0 W/cm2; irradiation power: 5 W; irradiation area: 2.5 cm2; 5 min). SOSG fluorescence was excited with a light source at a wavelength of 494 nm to a maximum of 525 nm following irradiation. The level of SOSG in the samples was evaluated by comparing the enhanced SOSG fluorescence measurement to that obtained for the control sample or background.