Abstract: The combination of chemotherapy and photothermal therapy can cover the entire tumor area, achieving a synergistic treatment performance effectively. In this study, COFs (DMTP - TAPB) with a unique pore structure and excellent chemical stability were utilized as the shell, and Fe3O4 nanoparticles with favorable photothermal properties were adopted as the core to construction a core-shell structured drug carrier with a particle size of approximately 200 nm. The antitumor drug doxorubicin hydrochloride (DOX) was encapsulated into the pores of COFs. Subsequently, the composite material was modified with the thermosensitive material poly(N - isopropylacrylamide) (PNIPAM), which was used to seal the surface of the composite. Furthermore, under irradiation with 808 nm laser, Fe3O4 nanoparticles rapidly converted light energy into heat energy, thereby generating a temperature change that achieve two purposes, on the one hand, the temperature change reached the lower critical solution temperature of PNIPAM for phase transition, causing the structure contracts inward and thus achieving the controlled release of drug molecules. On the other hand, the high temperature could kill cancer cells effectively, thus exhibited chemo-photothermal tumor therapy performance. Finally, carbon dots were grafted on the surface of the system to achieve the folic acid-mediated target controlled release mechanism, and a temperature-sensitive drug controlled release system was constructed successfully. The system exhibited highly antitumor performance by combine with chemotherapy and photothermal therapy.

Key words: Covalent organic frameworks, Nanocarrier, Drug delivery, Photothermal combined chemotherapy, Antitumor