Hierarchical Micro–Nano Porous Structure of Diatom Biosilica Induces Selective Absorption and Protease Inhibition for Bleeding Control

Diatom biosilica (DB), derived from the shells of diatoms,
is a
natural micronano inorganic porous material with excellent properties
for protein adsorption that show strong, powerful procoagulant activity.
However, the precise mechanism by which DB affects physiological processes
in blood has not been elucidated. Herein, we explore DB-initiated
blood coagulation at the molecular level, revealing that the selective
absorption and protease inhibition behavior induced by the size sieving
effect of DB can drive the blood system into a hypercoagulable state.
Unlike physiological coagulation, DB-induced blood coagulation displays
an unusual negative feedback regulation pattern, with exceptionally
selective absorption of antithrombin III and alpha-2-antiplasmin by
at least 10-fold and inhibition of their activity by more than 70%,
thus giving it super procoagulant activity. The animal studies confirmed
that DB could control bleeding in heparinized rats and rabbits within
5 min, demonstrating its potential application in hemorrhagic diseases.
Our findings provide a mechanistic understanding of how the hierarchical
porous structure of DB functionally contributes to blood coagulation,
providing insight into the design of improved hemostatic agents for
bleeding control.