Preparation of nanoscale hafnium-containing metal-organic frameworks for X-ray-promoted chemodynamic synergistic therapy

Nanoscale hafnium-containing metal-organic frameworks (Hf-nMOFs) with octahedral (Hf-MOFs-1) and sheet-like (Hf-MOFs-2) structures were synthesized by a solvothermal method using hafnium clusters as the connection point of the MOF, rigid dicarboxylic ligand 2,2 '-bipyridyl-5,5 '-dicarboxylic acid as the connector, acetic acid or trifluoroacetic acid and water as the structural regulator. Subsequently, a post-modification method was used to incorporate Fe3+ into the backbone of Hf-nMOFs, leading to the creation of multifunctional nMOFs, designated as Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2. In a mimic tumor microenvironment, the detection of hydroxyl radicals showed that X-ray irradiation significantly increased the generation efficiency of hydroxyl radicals in both Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2, with a more generation ability of sheet-like Hf-Fe-MOFs-2 than that of octahedral Hf-Fe-MOFs-1. Additionally, cellular assays demonstrated successful uptake of the Hf-nMOFs by cells and confirmed their efficacy in achieving low-dose X-ray-promoted chemodynamic synergistic therapy.