Achieving a “all in one” Fe/Tm-MOFs with controllable photothermal and catalytic performance for imaging-guided multi-modal synergetic therapy

Targeting excess H₂O₂ in the tumor microenvironment, nanotheranostic agents for catalytic therapy are designed based on Fenton reaction, catalyzing H₂O₂ into oxygen and hydroxyl radical (OH). But the catalytic efficiency in tumor microenvironment is not satisfactory. In order to solve the problem, a series of bimetallic-dual ligands metal-organic frameworks Fe/Tm-MOFs were designed, that Fe³⁺ and Tm³⁺ as metalions, 2-methylimidazole and trimesic acid as ligands. Due to the doped Tm³⁺ in Fe/Tm-MOFs and the conjugated structures formed by two ligands, the rate of electron transfer was improved, thus promoting the generation of OH at some extent. In addition, the photothermal effect of Fe/Tm-MOFs further promotes the generation of OH, which was evidenced by the 3,3′,5,5′-tetramethylbenzidine(TMB). Combining the drug loading and release capabilities of Fe/Tm-MOFs, synergetic therapy of photothermal/chemo-/catalytic therapy can be achieved. In vitro results reveal that DOX release behaviors are both pH- and thermal-responsive. In vivo anti-cancer results show that the tumors of mice almost disappeared within 10 days, which were injected with Fe/Tm-MOFs/DOX and irradiated with 808 nm for 10 min. Thus, an excellent therapeutic performance has been achieved. Besides, Fe/Tm-MOFs can serve as a multimodality bioimaging contrast agent, covering fluorescence imaging, photothermal imaging and magnetic resonance imaging. Thus, an all-in-one nanotheranostic agent is constructed, improving the catalytic efficiency and providing a novel method to design an efficient nanotheranostic agent.