Anisotropic Shape-Memory Cryogel with Oriented Macroporous Channel for Hemorrhage Control and Tissue Generation

Injectable shape-memory materials represent a promising solution for managing severe bleeding from deep, inaccessible wounds. However, many existing expandable hemostats consist of randomly porous networks and often exhibit inadequate liquid absorption, non-degradability, and potential cytotoxicity, which limits their effectiveness in hemostasis and wound repair. To overcome these challenges, this study introduces an anisotropic hemostatic cryogel, SALC, featuring oriented macroporous channels made from biocompatible polymers (poly(ethylene glycol), gelatin, and lignin) through a simple one-step cryo-structuration process. This structural alignment provides the cryogel with low water flow resistance, efficient fluid transport, and rapid shape recovery. SALC demonstrates superior liquid adsorption and retention, in vitro tamponade sealing, and pro-coagulant properties compared to commercial gelatin sponges and XSTAT, along with favorable biocompatibility and biodegradability. The hemostatic efficacy of SALC surpasses clinically used counterparts in rat models of liver perforation and femoral artery transection. Remarkably, SALC achieves effective hemostasis in porcine models of severe hepatic, femoral artery, and cardiac injuries. Additionally, this anisotropic cryogel supports liver tissue regeneration by promoting cell migration and angiogenesis while mitigating inflammatory responses. The cryogel is also lightweight and easy to carry and implement. Overall, SALC shows promising clinical applications for treating severe hemorrhages and improving wound healing.