Hafnium-Based Metal–Organic Framework Nanoparticles as a Radiosensitizer to Improve Radiotherapy Efficacy in Esophageal Cancer

[Image: see text] Radiotherapy is one of the most widely used clinical treatments for tumors, but it faces limitations, such as poor X-ray retention at the tumor site. The use of radiosensitizers containing high Z elements is an effective way to enhance X-ray absorption. Here, we demonstrate a simple one-step method for the synthesis of UiO-66-NH(2)(Hf) metal–organic framework nanoparticles for use as radiosensitizers in radiotherapy. The UiO-66-NH(2)(Hf) nanoparticles had a diameter of less than 100 nm and were stable in the physiological environment. UiO-66-NH(2)(Hf) induced apoptosis by enhancing X-ray absorption, as confirmed by in vitro and in vivo experiments. These characteristics make UiO-66-NH(2)(Hf) a promising radiosensitizer for esophageal cancer radiotherapy.