Fig. 1. Characterization of PCN-224. (a) Schematic of PCN-224 frame structure^[32]; (b) transmission electron microscopy image of PCN-224; (c) nitrogen adsorption-desorption curve; (d) PDT mechanism based on Jablon molecular energy level diagram

Fig. 2. Dark toxicity of PCN-224 material and MMAE load. (a) Survival of cell cultured with PCN-224 material for 24 h in the absence of light; (b) MMAE load curve; (c) mass spectrometry of MMAE

Fig. 3. Cytotoxicity and confocal imaging of PCN-224 material. (a) Survival of cell under different light conditions; (b) relationship between PCN-224 material concentration and cell viability; (c) detection of intracellular ROS level

Fig. 4. Therapeutic effect of PCN@MMAE nanocomposite drug. (a) Comparison of cytotoxicity of PCN-224 and PCN@MMAE under different conditions; (b) viability of cell after treating with different concentrations of PCN@MMAE (mass ratio is 1∶2) and PCN-224 under light condition