Porphyrin-based covalent organic frameworks as doxorubicin delivery system for chemo-photodynamic synergistic therapy of tumors

Photodynamic therapy (PDT) is a non-invasive treatment method that has garnered significant attention in recent years. Nanoparticle-based drug delivery systems can achieve targeted drug release, thereby significantly reducing side effects and enhancing therapeutic efficacy. In this study, a covalent organic framework (COF) with an approximately spherical structure connected by azo bonds was synthesized. The synthesized COF was utilized as a hypoxia-responsive carrier for doxorubicin (DOX) drug delivery and was modified with hyaluronic acid (HA). DOX@COF@HA exhibited a reactive release under hypoxic conditions. Under normal oxygen conditions, the release of DOX was 16.9 %, increasing to 60.2 % with the addition of sodium hydrosulfite. In vitro experiments revealed that the group combining photodynamic therapy with chemotherapy exhibited the lowest survival rates for 4T1 and MHCC97-L cells. In vivo experiments further validated the effectiveness of combination therapy, resulting in a tumor volume of only 33 mm