The hierarchical porous structures of diatom biosilica-based hemostat: From selective adsorption to rapid hemostasis

Here, we developed a Ca²⁺ modified diatom biosilica-based hemostat (DBp-Ca²⁺) with a full scale hierarchical porous structure (pore sizes range from micrometers to nanometers). The unique porous size in stepped arrangement of DBp-Ca²⁺give it selective adsorption capacity during coagulation process, resulted in rapid hemorrhage control. Based on in vitro and in vivo studies, it was confirmed that the primary micropores of DBp-Ca²⁺gave it high porosity to hold water (water absorption: 78.46 ± 1.12 %) and protein (protein absorption: 83.7 ± 1.33 mg/g). Its secondary mesopores to macropores could reduce of water diffusion length to accelerate blood exchange (complete within 300 ms). The tertiary stacking pores of DBp-Ca²⁺ could absorb platelets and erythrocytes to reduce more than 50 % of thrombosis time, and provided enough contact between Ca active site and coagulation factors for triggering clotting cascade reaction. This work not only developed a novel DBs based hemostat with efficient hemorrhage control, but also provided new insights to study procoagulant mechanism of inorganic hemostat with hierarchical porous structure from selective adsorption to rapid hemostasis.