Preparation and in vitro biological evaluation of strontium doped β-tricalcium phosphate scaffolds for alveolar bone tissue regeneration

Alveolar bone defects resulting from periodontitis or other oral tissue diseases have garnered significant attention in regenerative medicine. A range of strategies have been devised to boost the osteogenic differentiation capacity of various biomaterials. As a human trace element, strontium (Sr) plays a vital role in bone remodeling. This study examines the fabricated porous β-TCP scaffolds doped with 0 at. %, 4 at. %, and 8 at. % Sr (designated as Sr0-TCP, Sr4-TCP, and Sr8-TCP respectively), utilizing a modified negative pressure injection molding process, given the chemical similarity between β-TCP and natural bone. Extensive research was conducted on the impact of Sr doping on the composition, microstructure, mechanical behavior, degradation, and biological activity of β-TCP. Materials characterization demonstrated the successful fabrication of high-purity Srx-TCP scaffolds with similar porous structures. The density enhanced with the increasing amount of Sr, achieving a compressive strength of 3.86 MPa in the Sr8-TCP scaffold, meeting the criteria for cancellous bone implantation. Confocal laser scanning microscopy analysis revealed that Srx-TCP offered favorable circumstances for cell adhesion. The alkaline phosphatase assay and mineralization staining confirmed the osteogenic differentiation potential of Srx-TCP in vitro, particularly evident in the Sr8-TCP scaffold. Overall, the experimental results indicate the remarkable biocompatibility and outstanding osteogenic differentiation ability of Srx-TCP scaffolds. This research suggests that Srx-TCP scaffolds, characterized by applicable compressive strength, hold promise as a viable candidate for alveolar bone tissue regeneration.