Porous Silica Material as Hemostatic Dressing for Acute Blood Loss: Influence of Pore Structure

Porous silica materials can serve as hemostats, offering a promising approach to promote the coagulation speed. The pore structure of porous silica is a critical property, which may influence the hemostatic effectiveness, though its exact role in the hemostasis process remains unclear. Given that the key structural parameters of porous silica, including pore size, surface area, and pore volume, exhibited strong interrelationships that significantly influence each other, we prepared porous silica with pore sizes ranging from 2.5 to 50 nm to study their hemostatic effects by both in vitro and in vivo assessments. The results demonstrated that the mesoporous material MCM-41 with small pore size (2.5 nm) and high specific surface area exhibited superior contact activation capability to the coagulation pathway. In contrast, the macroporous siliceous foam (MSF) with large pore size (50 nm) and large pore volume showed enhanced absorption of blood cells and proteins. The mesoporous SBA-15 with pore size of 5.3 nm displayed intermediate properties between the two materials. The in vivo experiments showed that among the three kinds of porous silica, the MCM-41 provided the highest pro-coagulant capacity in the tail transection rat model with minor bleeding, and the MSF performed the best hemostatic effect in the femoral artery injury rat model with spurting hemorrhage. Our study elucidates the role of pore structure of porous silica as hemostats, which may give hint to the design of such materials.