Figure 8.

(A) Simplified Jablonski diagram showing the different energy transfer events involved in PCI. PS: photosensitizer, ICS: intersystem crossing. (B) Schematic illustration of the PCI process. Delivery systems (DS) and photosensitizers (PS) are endocytosed by the cell and colocalized into the endosomal vesicles. PS are mainly localized in the endosomal membranes due to their amphiphilic properties. After NIR irradiation, PS absorb the light energy and transfer it to molecular oxygen, thereby generating highly toxic singlet oxygen. These molecules cause important oxidative damage in the endocytic membranes, which ultimately leads to endosomal escape by their disruption. (Created with BioRender.com).