Injectable dry cryogels with excellent blood-sucking expansion and blood clotting to cease hemorrhage for lethal deep-wounds, coagulopathy and tissue regeneration

Designing expandable dry cryogels with biodegradability, rapid blood-sucking expansion and hemostasis for lethal non-compressible hemorrhage and coagulopathy hemorrhage still remains a challenge. Herein, we designed a series of antioxidant, photo-thermal and antibacterial expandable dry cryogels based on polydopamine crosslinked chitosan. The cryogels presented excellent antioxidant activity, outstanding NIR-enhanced antibacterial activity, rapid thrombin release, better blood clotting capacity, and higher blood cells/platelets adhesion and activation than Combat Gauze and gelatin sponge. Besides, all the cryogels showed less blood losses than Combat Gauze and gelatin sponge in mouse liver trauma model, and CS20/PDA4.5 (prepared by 20 mg chitosan and 4.5 mg dopamine) showed the least blood loss. Moreover, CS20/PDA4.5 presented much better hemostatic performance than Combat Gauze and gelatin sponge in rabbit liver non-compressible hemorrhage model with and without administrating anticoagulant. Especially, CS20/PDA4.5 presented excellent hemostatic performance in lethal non-compressible swine subclavian artery and vein transection model. Furthermore, the cryogel showed better wound healing performance than chitosan sponge and Tegaderm (TM) film. This facile approach opens up new avenue to develop expandable dry cryogels hemostats for lethal non-compressible hemorrhage, coagulopathy hemorrhage and tissue engineering.