A hierarchical Chitosan-Alginate composite scaffold with surface Retention-Internal concentration synergy for efficient and atraumatic hemostasis in deep trauma

• A CS-SA scaffold with alginate nanofiber/tannic acid blood cell barrier was designed. • The scaffold realizes synergistic efficient hemostasis and antibacterial protection. • This work provides a new approach for efficient hemostatic materials. Deep non-compressive traumatic hemorrhage carries a high mortality rate. Existing hemostatic sponges are prone to cause secondary injury during removal due to blood cell entrapment, a critical clinical paradox that urgently demands resolution. In this study, a chitosan-alginate nanofibrous composite hemostatic sponge was constructed, featuring a core innovation of a surface blood cell-repellent layer. Through Ca 2+ crosslinking, the sponge achieves selective sieving with blood cell retention and plasma permeability. This design not only accelerates surface clot formation to enhance hemostasis but also avoids blood cell entrapment for atraumatic removal. In vitro and in vivo experiments verified that the sponge exhibits significantly superior hemostatic efficacy compared to commercial counterparts, reducing blood loss by over 40%, while also possessing favorable biocompatibility and antibacterial activity. This work resolves the functional contradiction of traditional hemostatic materials, proposes a structure zoning-function targeting design paradigm, and provides a high-performance solution for emergency hemostatic materials in deep trauma, holding substantial potential for clinical translation.