Biphasic calcium phosphate/polyvinyl alcohol scaffolds prepared by 3D-printing at room temperature and their impact on in vitro osteogenic differentiation

Abstract

Objective To prepare biphasic calcium phosphate/polyvinyl alcohol scaffolds by 3D printing at room temperature and explore the effect of 3D scaffolds on in vitro osteogenic differentiation of the bone marrow mesenchymal stem cells (BMSCs). Methods After biphasic calcium phosphate and polyvinyl alcohol solutions were mixed, the biphasic calcium phosphate/polyvinyl alcohol composite scaffolds were prepared by room temperature 3D printing combined with freeze drying technique. Non-printing scaffolds were prepared by injection molding. The surface microstructure, porosity, elastic modulus and hydrophilicity of the 2 sorts of scaffolds were measured. The cytological experiments were carried out in 3 groups (n=3): printed scaffold group, non-printed scaffold group and blank control group (no scaffold). After the BMSCs were seeded onto the scaffolds for 7 and 14 days, the 3 groups were compared in terms of cellular proliferation, alkaline phosphatase activity and expression levels of osteogenesis-related genes. Results 3D composite scaffolds with controllable pore size and porosity were prepared successfully, with an average porosity of 59.6%±3.6% and an average elastic modulus of 429.3±54.3 kPa. After culture for 7 and 14 days, the cellular absorbance values in the printed scaffold group (0.987±0.047 and 1.497±0.076) were significantly higher than those in the non-printed scaffold group (0.767±0.063 and 1.181±0.098) (P 0.05), but were significantly higher than those in the blank control group (P< 0.05). Conclusions Tissue-engineered composite biphasic calcium phosphate/polyvinyl alcohol scaffolds with controllable pore size and good connectivity can be prepared by freeze-drying and room temperature 3D printing techniques. Co-culture of the scaffolds and BMSCs in vitro promotes adhesion, proliferation and osteogenic differentiation of the cells. Key words: Tissue engineering; Biocompatible materials; Cell proliferation; Osteodifferentiation; 3D printing