Janus Self-Propelled Chitosan-Based Hydrogel Spheres for Rapid Bleeding Control.

Uncontrolled hemorrhage is a major cause of potentially preventable death in civilian trauma nowadays. Considerable concern has been given to the development of efficient hemostats with high blood absorption, self-propelled property, and Ca 2+ release ability, for irregularly shaped and noncompressible hemorrhage. Herein, Janus self-propelled chitosan-based hydrogel with CaCO 3 (J-CMH@CaCO 3 ) is developed by partial ionic crosslinking of carboxylated chitosan (CCS) and Ca 2+ , gravity settlement, and photopolymerization, followed by removing the shell of CCS. The obtained J-CMH@CaCO 3 is further used as a hemostat powered by the internal CaCO 3 and coordinated protonated tranexamic acid (J-CMH@CaCO 3 /T). Bubbles are generated and detached to provide the driving force, accompanied by the release of Ca 2+ . The two aspects work in synergy to accelerate clot formation, endowing the J-CMH@CaCO 3 /T with excellent hemostatic efficiency. The J-CMH@CaCO 3 /T presents high blood absorption, favorable blood-clotting ability, desired erythrocyte and platelet aggregation, and acceptable hemocompatibility and cytocompatibility. In rodent and rabbit bleeding models, the J-CMH@CaCO 3 /T exhibits the most effective hemostasis to the best knowledge of the authors, wherein the hemorrhage is rapidly halted within 39 s. It is believed that the J-CMH@CaCO 3 /T with self-propelled property opens up a new avenue to design high-performance hemostats for clinical application.