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, Bacillus cereus (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 in vitro/in vivo 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.