Hydrothermally fabricated chitosan-alginate polyelectrolyte complex-based hemostatic patches with shape recovery

Rapid control of blood loss upon trauma remains a predominant challenge in the medical and military settings. Most commercially available hemostats fail to achieve rapid hemostasis, shape recovery, and biocompatibility simultaneously, limiting their effectiveness in managing non-compressible hemorrhage. Herein, we report a novel crosslinker-free chitosan-alginate polyelectrolyte complex (PEC)-based hemostatic patch fabricated solely through hydrothermal treatment and freeze-drying, eliminating the need for chemical crosslinkers while preserving mechanical integrity and biofunctionality. The thermal treatment induced intermolecular hydrogen bonding between chitosan and alginate PEC, leading to physical gelation. This crosslinker-free strategy yielded highly biocompatible (cell viability >90%) and hemocompatible (hemolysis <2%) patches. The patches demonstrated significantly shorter in vitro hemostasis time (57 ± 6 s) than a commercial hemostat (127 ± 3 s). The highly porous architecture enabled rapid blood absorption and enhanced blood cell adhesion. The decreased activated partial thromboplastin time (aPTT) indicated an intrinsic mode of coagulation. The patches exhibited fluid-triggered shape recovery within 20 s in blood. Finally, in an in vivo rat liver injury model, the patch exhibited a shorter clotting time (141 ± 28 s) and less blood loss compared to the untreated group (238 ± 11 s). This study highlighted the potential of a PEC-based hydrothermal hemostatic shape-recovery patch for managing non-compressible hemorrhage.