Dissolution behavior and bioactivity study of glass ceramic scaffolds in the system of CaO–P 2O 5–Na 2O–ZnO prepared by sol–gel technique

Abstract

Three-dimensional glass ceramic scaffolds from the system CaO–P 2O 5–Na 2O–ZnO have been prepared by coating polyurethane foams with sol–gel derived glass slurry. Main phase catena hexaphosphate (Ca 4P 6O 19), minor phases calcium pyrophosphate (β-Ca 2P 2O 7) and calcium metaphosphate (β-Ca(PO 3) 2) were detected in the prepared glass ceramics. In order to assess the potential use in hard tissue engineering, the dissolution and precipitation behavior of the glass ceramics was investigated in vitro after soaking in simulated body fluid (SBF) for different periods of time, and the bioactivity and biocompatibility studies were conducted using mouse MC3T3-E1. Ca 4P 6O 19 phase showed a good chemical durability in SBF solution over the period time of soaking. However, there were small quantities of apatite-like deposits formed on the surfaces after soaking 28 days, exhibiting a poor ability of inducing calcification in SBF. In vitro cell culture, a high degree of cell adhesion and spreading was achieved and large number of mineralized deposits composed of Ca, P and Zn were detected in these porous scaffolds. These results confirmed the biocompatibility and bioactivity of the glass ceramics and the positive effects on mouse MC3T3-E1 cell behavior although no continuous apatite layer was formed on scaffold surfaces after soaking in SBF, and also demonstrated that Zn doped this glass ceramics could strongly stimulate the formation of mineralized deposits in vitro culture of MC3T3-E1 cells.