The 4T1 cells (4×103 cells/well) were seeded in 96-well plates and incubated overnight. The materials (2, 5 and 10 μM) were added to each group, and the cells were cultured for 24 h. The cell viability was measured at 24 h after irradiation with light at a wavelength of 808 nm (power density: 2.0 W/cm2, 5 min) using a CCK-8 kit. To compare the PDT and PTT effects of ICG alone and the prepared PHSA-ICG-TAT, the materials were stimulated under different conditions to assess their lethality to tumor cells. ICG and PHSA-ICG-TAT (10 μM) were added to the cells for 24 h. The cells were irradiated with light at a wavelength of 808 nm for 5 min (power density: 2.0 W/cm2) under different conditions (25°C, 4°C, addition of 4 μM NaN3 0.5 h before light irradiation). After 24 h of incubation, the cell viability was measured with a CCK-8 kit.