Preparation and chemical stability of CaO–P2O5–Na2O–B2O3 porous glass ceramics

CaO–P2O5–Na2O–B2O3 (CaO/P2O5 molar ratio is 1.25) glass ceramic scaffolds with good bioactivity and chemical stability for tissue engineering applications have been prepared by coating polyurethane foams with glass slurry, and subsequent heat treatment of the obtained porous structures. When heat treated at 700 °C for 1 h, the resultant foam structure has a porosity of 67–72%, and fine crystals of CaP2O6, Ca(PO3)2 and BPO4 crystallized and precipitated homogeneously in the glass matrix which conferred the scaffolds a high mechanical property. The scaffolds were soaked in the simulated body fluid to determine the solubility and observe apatite formation. The results show that B2O3 plays an important role in the crystallization of the glass and can improve the chemical stability. And the formation of an apatite-like layer covering certain areas of the scaffold surface exhibited a good ability of inducing calcification in the simulated body fluid. In vitro cell studies showed that cells exhibit normal morphologies and spread well on the scaffold specimens, indicating that the glass ceramics were biocompatible.