Cryochemically Engineered Sponges with Directional Channels and Anisotropic Surfaces for Improved Hemorrhage Control

Effective management of severe hemorrhage remains a critical clinical challenge, necessitating advanced hemostatic materials capable of rapid fluid absorption and enhanced coagulation. Here, we introduce a scalable unidirectional freezing method at moderately elevated temperatures (−30 °C) to fabricate chitosan-based cryosponges featuring directional channels with superior liquid absorption properties. The liquid absorption dynamics were rigorously validated using the Box-Lucas and Washburn equations, revealing a predictive scaling relationship ( v ∼ d 5 / 2 ) between absorption velocity ( v ) and directional channel width ( d ). Furthermore, anisotropic surfaces were controllably engineered within these channels via cryopostmodification using polymerized tannic acid (PTA), significantly promoting interactions with blood-clotting components. These structurally and chemically optimized sponges exhibited rapid blood coagulation initiation, superior platelet adhesion, and enhanced erythrocyte capture efficiency in vitro, as demonstrated through dynamic coagulation and quantitative cell adhesion assays. In vivo evaluations in a mouse liver injury model confirmed their exceptional hemostatic performance, markedly reducing blood loss and shortening hemostatic times relative to conventional sponge controls. Additionally, a semiconductor-based numerical control freezing platform facilitated reproducible and scalable fabrication of cryosponges across various dimensions. This study presents a promising strategy for designing clinically relevant hemostatic materials for emergency hemorrhage management.