Facile and green approach towards biomass-derived hydrogel powders with hierarchical micro-nanostructures for ultrafast hemostasis

Although a series of biomass-derived hemostats has been developed, the desire for green-prepared hemostatic materials with biosafety has not decreased. Herein, we constructed porous carboxymethyl chitosan/sodium alginate/Ca(OH)2 powders (PCSCPs) with suitable adaptability for instant control of irregular hemorrhage via a facile and green approach. By one-pot chemical crosslinking of carboxymethyl chitosan and sodium alginate, hydrogels were formed and immediately ionically cross-linked along with the generation of Ca(OH)2 to prepare PCSCPs. As hydrogel powders, PCSCPs with abundant hydrophilic carboxymethyl groups and porous hierarchically micro-nanostructures displayed a high water absorption ratio of over 1600%. The PCSCPs were confirmed with favorable hemocompatibility, non-cytotoxic effects and excellent degradability. Hemostasis assays in vitro showed that PCSCPs possessed an outstanding property of platelet activation and red blood cell aggregation. The PCSCPs effectively shortened the hemostatic time and blood loss to ca. 50% in rodent bleeding models compared with medical gauze and commercial chitosan-based hemostats. Furthermore, a mouse subcutaneous implantation model demonstrated an ignorable inflammation response and potential tissue repair capability of PCSCPs. It's believed that green-prepared and biomass-derived PCSCPs are feasible biomedical hemostatic materials in view of engineering and provide a promising platform to design hemostats in prehospital management and clinical settings.