Sintering of nano-porous biosilica diatoms for tissue scaffolding

Abstract In this paper, we discuss the effects of sintering temperature on the properties of diatomite ceramic biomaterials. Diatomite from Cyclostephanos sp. was sintered at 950 °C, 1100 °C, and 1250 °C to evaluate how thermally driven phase transitions, pore architectures, and wetting behaviour govern its application for cell culturing and tissue scaffolding. X-ray diffraction revealed that sintering at 1100 °C and 1250 °C produced predominantly β−cristobalite ceramics, whereas 950 °C samples retained substantial amorphous silica, leading to rapid disintegration in aqueous media and exclusion from biological testing. Model endothelial cells (MDCK-2) exhibited good adhesion and proliferation on both 1100 °C and 1250 °C ceramics, with significantly higher cell densities observed on 1250 °C samples from days 6-8. Image-based pore analyses revealed that 1250 °C sintering generated larger and more numerous micron-scale pores, as well as a 1.18-fold increase in water imbibition velocity, suggesting enhanced early-stage cell attachment via improved capillarity and surface accessibility. Both materials have shown similar efficacy as bioplatforms for pre-osteoblasts (MC3T3-E1) differentiation and mineral deposits formation. Collectively, the results show that sintering temperature critically determines crystalline phase, mechanical stability, and pore morphology, which in turn affects cell proliferation rate.