PDT treatment

When the tumor size reached ~100 mm³, mice received an intravenous injection of 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-alpha (HPPH)¹⁸ (0.47 μmol/kg). At 24 h post-injection, mice were anesthetized by inhalation of isoflurane (1% in 1 L/min oxygen). Each mouse was exposed to laser irradiation at a wavelength of 671 nm (Laserglow Technologies, ON, Canada) with a fluence of 75 mW/cm² for 30 min¹⁹. Laser energy was measured by a LPE-18 laser energy meter (Coherent Portland, OR, USA). During PDT treatment process, mice were positioned in a specially-designed mouse holder, and were anesthetized by inhalation of isoflurane (1% in 1 L/min oxygen).