Porphyrin-copper (II) covalent organic framework nanoplatform with intrinsic bifunctional photodynamic and chemodynamic activities for synergistic multimodal cancer therapy
Photodynamic therapy (PDT) efficacy is severely compromised by tumor hypoxia and the scarcity of efficient type-I photosensitizers, necessitating multimodal therapeutic strategies. Herein, we report a porphyrin-Cu (II) covalent organic framework (TBCOF) with intrinsic bifunctional photodynamic and chemodynamic activities. Sequential DOX encapsulation and hyaluronic acid (HA) surface functionalization afford HA-TBCOF@DOX, a tumor-targeted nanoplatform integrating four synergistic therapeutic modalities. Under 660 nm laser irradiation, the nanoplatform generates ROS signatures consistent with both type-I and type-II pathways for PDT, while the intrinsic Cu2+ centers are proposed to catalyze a Fenton-like reaction consistent with •OH generation for CDT. Concurrently, observations of O2 evolution suggest catalase-like activity that may decompose endogenous H2O2 into O2, alleviating hypoxia and potentiating oxygen-dependent PDT. Efficient photothermal conversion and pH-triggered DOX release contribute to photothermal and chemotherapeutic effects, respectively, while HA-mediated CD44 targeting enhances cellular uptake and therapeutic specificity. In vitro and in vivo studies demonstrate that laser-activated HA-TBCOF@DOX effectively suppresses tumor growth, induces apoptosis, and exhibits no apparent systemic toxicity under the tested experimental conditions. This work establishes a multifunctional COF-based nanoplatform that addresses PDT limitations observed in this study by integrating intrinsic PDT and CDT, providing a robust strategy for synergistic multimodal cancer therapy.