Polydopamine/chitosan layer-by-layer coating of Bacillus cereus enhances the robustness of live anti-oxidation materials for the treatment of radiation enteritis

Radiation enteritis (RE) is a common disease following radiotherapy in patients with abdominal and pelvic malignant tumors, but no specific medications are available. Probiotics, as a potential biological antioxidant, have become an emerging live therapeutic for RE; however, their fragile nature in the gastrointestinal tract and colonization resistance hinder their clinical application. Here, <i>Bacillus cereus</i> (BC) was selected among several marketed probiotic strains due to its strong antioxidant ability. A polydopamine (PDA)/chitosan layer-by-layer coating highly enhanced the robustness of BC to obtain live anti-oxidation materials. The physically engineered BC, namely BC@PCS, showed high tolerance to the harsh environments, including ionizing radiation, freeze drying, long-term preservation at room temperature, and gastric acid. More importantly, the coating improved the <i>in vitro</i>/<i>in vivo</i> ROS-scavenging ability of live materials and prolonged their intestinal retention. After BC@PCS was orally administered to the 12-Gy γ-ray abdomen-irradiated mice, the RE symptoms were highly alleviated, rather than those of the BC, PDA/chitosan mixture, and BC/PDA/chitosan mixture groups, involving body weight, intestinal length, tissue histopathology, local ROS clearance, local inflammation, and mucosal permeability. Layer-by-layer coating is a promising approach to enhance the robustness of live materials for disease treatment.