Preparation of micro-porous bioceramic containing silicon-substituted hydroxyapatite and beta-tricalcium phosphate

- Bone grafts consist of 70% Si-HA, 30% β-TCP, and calcium silicate were fabricated by a simple sol-gel and sinter process.
- This micro-porous bioceramic has high specific surface area, less sintering shrinkage and possesses comparable strength.
- A better viability for D1 mice stem cells cultured on TEOS treated HA was demonstrated when compared to the pure HA.

Dimensional instability caused by sintering shrinkage is an inevitable drawback for conventional processing of hydroxyapatite (HA). A new preparation method for biphasic calcium phosphates was developed to increase micro pores and biodegradation without significant dimensional change. Powder pressed HA discs, under 100 MPa, were immersed in a colloidal mixture of tetraethoxysilane (TEOS) and ammonium hydroxide for 10 min, followed by drying, and then were sintered at 900 °C, 1050 °C, and 1200 °C, respectively. Comparing with pure HA discs, the newly prepared product sintered up to 1200 °C contained silicon substituted HA, beta-tricalcium phosphate, and calcium silicate with better micro-porosity, high specific surface area, less sintering shrinkage and the strength maintained. The cytocompatibility test demonstrated a better viability for D1 mice stem cells cultured on TEOS treated HA for 14 days compared to the pure HA. This simple TEOS sol-gel pretreatment has the potential to be applied to any existing manufacturing process of HA scaffold for better control of sintering shrinkage, create micropores, and increase biodegradation.

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