Tantalum-doped β-TCP porous bioceramic scaffolds: In vitro and in vivo evaluation of biodegradation and osteoinductive properties

The development of biodegradable bone substitutes with balanced mechanical properties, osteogenic activity, and controlled degradation remains a critical challenge in bone tissue engineering. In this study, in situ doping Ta-doped β-tricalcium phosphate(β-TCP) powders were synthesized via a microwave-ultrasound-assisted method, and porous bioceramic scaffolds were prepared from this material. The effects of Ta doping concentration on the scaffolds' physicochemical properties, in vitro and in vivo biological safety and osteogenic properties of the scaffolds were systematically evaluated. The results showed that Ta⁵⁺ incorporation significantly improved structural stability and enhanced compressive strength from 5.65 MPa (pure β-TCP) to 9.84 MPa (2.5 % Ta group), while maintaining high porosity (65.98 %). In vitro, the scaffolds showed excellent cytocompatibility with cell viability exceeding 90 %, and the 2.5 % Ta group exhibited the most substantial promotion of osteogenic differentiation, as evidenced by enhanced ALP activity and calcium deposition. In vivo experiments further confirmed superior bone regenerative performance, with the 2.5 % Ta group achieving a bone volume fraction (BV/TV) of 42.29 % at 12 weeks, significantly higher than the 22.27 % observed in pure β-TCP. These findings underscore the role of Ta in simultaneously improving mechanical integrity, biodegradation kinetics, and osteoinductivity, establishing 2.5 % Ta-doped β-TCP as a highly promising scaffold for clinical bone regeneration applications.