A tailored hydroxyapatite/magnesium silicate 3D composite scaffold: Mechanical, degradation, and bioactivity properties

Abstract

Today, hydroxyapatite (HA)-based composite scaffolds are widely studied, but there is a lack of a doping method that can simultaneously improve the mechanical strength, degradation rate, and bioactivity of HA scaffolds. In this paper, the amorphous magnesium silicate (MS) with a low melting point is selected as the doping phase of HA. The hydroxyapatite/magnesium silicate composite was fabricated using photocuring technology. In addition, at high temperatures, ionic substitution can occur between the magnesium silicate glass phase and the HA lattice. Therefore, a new phase with a pinning effect can be obtained at the grain boundary and the magnesium silicate can further improve the biocompatibility of HA scaffolds. In the sintering process, the magnesium silicate was melted to a liquid state, and then the sintering temperature of the scaffold was reduced for grain refinement. The morphological analysis shows that MS doping is an important factor for grain refinement, which has been reduced from 12 μm to 6 μm. Furthermore, the formation of new diopside and whitlockite phases with a pinning effect has been observed at the grain boundaries. Specifically, the compressive stress of the composite scaffold is increased by 59.15% compared to the pure HA scaffold. However, the soaking and cell experimental findings show that the composite scaffold has a better degradation rate, cell activity, and bone induction. Finally, this study found that a composite scaffold with improved mechanical strength, degradation performance, and biocompatibility can be obtained with the addition of magnesium silicate as the doping phase of HA with 30 wt% of.