Smart Oral Administration of Polydopamine‐Coated Nanodrugs for Efficient Attenuation of Radiation‐Induced Gastrointestinal Syndrome

Abstract High‐dose ionizing radiation can lead to death from the unrecoverable damage of the gastrointestinal tract, especially the small intestine. Until now, the lack of predilection for the small intestine and rapid clearance by digestive fluids limit the effects of conventional radioprotective formulations. Herein, an innovative radioprotective strategy is developed for attenuating gastrointestinal syndrome by smart oral administration nanodrugs. The nanodrug is first engineered by encapsulating thalidomide into chitosan‐based nanoparticles, and then coated with polydopamine. The behaviors of gastric acid‐resistance, and pH‐switchable controlled release in the small intestine enhance the oral bioavailability of the pyroptosis inhibitor thalidomide. In a mouse model, nanodrugs demonstrate prolonged small intestinal residence time and accessibility to the crypt region deep in the mucus. Furthermore, the nanodrugs ameliorate survival rates of C57BL/6J mice irradiated by 14 Gy of subtotal body irradiation and also maintain their epithelial integrity. This work may provide a promising new approach for efficiently attenuating lethal radiation‐induced gastrointestinal syndrome and add insights into developing nanodrug‐based therapies with improved efficacy and minimum side effects.