An improved blood hemorrhaging treatment using diatoms frustules, by alternating Ca and light levels in cultures

Hemorrhage control requires hemostatic materials that are both effective and biocompatible. Among these, diatom biosilica (DBs) could significantly improve hemorrhage control, but it induces hemolysis (the hemolysis rate > 5%). Thus, the purpose of this study was to explore the influence of Ca²⁺ biomineralization on DBs for developing fast hemostatic materials with a low hemolysis rate. Here, CaCl₂ was added to the diatom medium under high light (cool white, fluorescent lamps, 67.5 µmol m⁻² s⁻¹), producing Ca-DBs-3 with a particle size of 40–50 μm and a Ca²⁺ content of Ca-DBs-3 obtained from the higher concentration CaCl₂ group (6.7 mmol L⁻¹) of 0.16%. The liquid absorption capacity of Ca-DBs-3 was 30.43 ± 0.57 times its dry weight; the in vitro clotting time was comparable to QuikClot^® zeolite; the hemostatic time and blood loss using the rat tail amputation model were 36.40 ± 2.52 s and 0.39 ± 0.12 g, which were 40.72% and 19.50% of QuikClot^® zeolite, respectively. Ca-DBs-3 showed no apparent toxicity to L929 cells (cell viability > 80%) and was non-hemolysis (the hemolysis rate < 2%). This study prepared Ca-DBs-3 with a rapid hemostatic effect and good biocompatibility, providing a path to develop diatom biosilica hemostatic materials.