π-Extended Benzoporphyrin-Based Metal-Organic Framework for Inhibition of Tumor Metastasis.

We report on the benzoporphyrin-based metal-organic framework (TBP-MOF), with 10-connected Zr6 cluster and much improved photophysical properties over the traditional porphyrin-based MOFs. It was found that TBP-MOF exhibited red-shifted absorption bands and strong near-infrared luminescence for bioimaging, whereas the π-extended benzoporphyrin-based linkers of TBP-MOF facilitated 1O2 generation to enhance O2-dependent photodynamic therapy (PDT). It was demonstrated that poly(ethylene glycol)-modified nanoscale TBP-MOF (TBP-nMOF) can be used as an effective PDT agent under hypoxic tumor microenvironment. We also elucidated that the low O2-dependent PDT of TBP-nMOF in combination with αPD-1 checkpoint blockade therapy can not only suppress the growth of primary tumor, but also stimulate an antitumor immune response for inhibiting metastatic tumor growth. We believe this TBP-nMOF has great potential to serve as an efficient photosensitizer for PDT and cancer immunotherapy.