Diatoms, known as photosynthetic unicellular algae, can produce natural biosilica frustules that exhibit great biocompatibility, superhydrophilicity, and superhemophilicity. In our study, the diatom Navicula australoshetlandica sp. was isolated from aquaculture wastewater and pretreated to obtain frustules so as to explore their hemostasis characteristics. A special "porous web" (6-8 nm) substructure in the ordered nanopores (165-350 nm) of boat-shaped diatom frustule was observed in Navicula australoshetlandica sp. using SEM and TEM analysis. Moreover, X-ray, N2 adsorption-desorption isotherms, and BET analysis showed that the diatom frustule is a mesoporous material with a surface area of 401.45 m2 g-1 amorphous silica. FTIR analysis showed that Navicula australoshetlandica sp. frustules possessed abundant OH functional groups. A low hemolysis ratio was observed for 1-5 mg mL-1 diatom frustules that did not exceed 1.55 ± 0.06%, which indicates favorable hemocompatibility. The diatom frustules exhibited the shortest clotting time (134.99 ± 7.00 s) with a hemostasis material/blood (mg/μL) ratio of 1:100, which is 1.83 times (112.32 s) shorter than that of chitosan. The activated partial thromboplastin time (aPTT) of diatom frustule was also 44.53 s shorter than the control. Our results demonstrate the potential of Navicula australoshetlandica sp. diatom frustules to be used as medical hemostasis material.
Keywords: Navicula australoshetlandica sp.; biosilica frustule; hemocompatibility; hemostasis characteristics; mesoporous biomaterial.