“…PDT is highly efficient, spatiotemporal selective, not easy to produce drug resistance, and its killing effect is limited to tens of nanometers. However, most current PDT systems promote the formation of ROS through type II mechanisms, which makes the activation of PDT systems very dependent on oxygen ( Mukai et al, 2018 ). In recent years, some scholars have also studied the use of type I mechanism photosensitizers to reduce dependence on oxygen ( Huynh and Zheng, 2013 ; Li et al, 2018b ).…”