Scheme 1.

The schematic illustration of image-guided PDT mediated by cRGD-modified TPETS (T-TPETS) nanodots in xenograft tumor model. The T-TPETS nanodots are administered systemically. After a period of systemic distribution, the nanodots selectively accumulate into the tumor via both passive targeting (enhanced permeability and retention effect) and active targeting (receptor-mediated endocytosis). Upon light irradiation, the fluorescence depicts the tumor outline. Further irradiation activates the nanodots and trigger a photochemical reaction to result in the production of ROS. Irreparable damage induces tumor cell death via an apoptotic and/or necrotic pathway.