Radially Aligned Microchannels in a Hemostatic Sponge: Orchestrating Directional Transport, Active Sieving, and Coagulation.

Abstract

Uncontrollable bleeding from non-compressible bone defects remains a significant clinical challenge. While silk fibroin-based hemostatic sponges hold promise, their development is plagued by the inherent conflict between rapid water absorption and poor dimensional stability. Herein, a combination of radially aligned microchannel architecture and a stable crosslinked network is designed to overcome this limitation. The sponge is fabricated via directional freezing and stabilized using a crosslinker, ethylene glycol diglycidyl ether. The formed elastic network reconciles mechanical robustness (2.4-fold increase in Young's modulus). The radial architecture creates a Laplace pressure gradient, enabling ultra-fast fluid absorption (16-fold) and blood cell sieving. Furthermore, surface modification with chitosan confers a positive charge, facilitating strong electrostatic adhesion to blood cells via a mechanism unraveled by molecular dynamics simulations, which reveal a binding free energy of -107.93 kcal/mol. By synergistically integrating thrombin protein corona particles, the final construct orchestrates a dual hemostatic mechanism: rapid physical blood cell sieving/enrichment, and activated biological coagulation. This synergy delivers exceptional hemostatic performance in rat calvarial defect models, achieving hemostasis in 64 s, faster than the 185 s required by the random sponge. This study provides a novel paradigm for developing high-performance hemostatic materials through rational structural and multi-mechanistic integration.