Blood clot inspired pore‐gradient nanofiber sponge with “outer filtration” and “inner adsorption” bifunction for rapid stop of uncontrolled hemorrhage

Abstract Effectively controlling deep non‐compressible bleeding remains a major challenge. In this study, by mimicking nanofiber structure and netting blood cells function of fibrin network in blood clots, we develop a novel bioinspired quaternized chitosan nanofiber sponge with distinct blood cells filtration and blood plasma absorption bifunction for rapid hemostasis. The quaternized chitosan nanofiber sponge possesses a unique gradient pore structure with small pores on the outer surface and large pores in the inner part. The outer small pores effectively capture blood cells with a filtration efficiency as high as 91.7%, while the inner large pores endow with an ultrahigh liquid absorption capacity (93 g/g), surpassing previously reported literature records. The quaternized chitosan nanofiber sponge demonstrates a hemostasis time 2.5 times faster than that of the commercial gelatin® hemostatic sponge when treating the rat liver defect bleeding (noncompressible hemorrhage model). When applied to the rabbit arterial injury bleeding (lethal arterial hemorrhage model), the bioinspired nanofiber sponge achieves bleeding control within only 61.6 s, while both commercial gelatin® hemostatic sponge and commercial collagen® hemostatic sponge fail to stop bleeding even after 240 s. This bioinspired nanofiber sponge derived from the physiological coagulation process may hold great potential for pre‐hospital and battlefield first aid.