Preparation of injectable 3D-formed β-tricalcium phosphate bead/alginate composite for bone tissue engineering

Abstract

A novel, injectable bone tissue engineering material was developed that consisted of β-tricalcium phosphate (β-TCP) beads as the solid phase and alginate as the gel phase. To prepare the instantaneously formed composite scaffold, an aqueous calcium chloride solution was dried on the surface of β-TCP beads and crosslinked with an alginic acid sodium solution, thereby forming stable β-TCP beads and alginate gel which were injectable via a syringe. This biodegradable composite was a three-dimensional (3D) material that could be used as an injectable scaffold for bone tissue engineering. In particular, the composite with 2.0 wt% alginate concentration exhibited a compressive strength of 69 kPa in dry conditions, which was significantly higher than that exhibited by 1.0 wt%. Furthermore, mesenchymal stem cells (MSC) were 3Dcultured within the composite and then investigated for osteogenic markers. MSC-loaded composite was subjected to scanning electron microscope (SEM) examination and implanted subcutaneously for in vivo experiment. Results showed that the scaffold provided support for osteogenic differentiation. In light of the encouraging results obtained, this novel injectable composite material may be useful for bone tissue engineering.