In Vitro and In Vivo Evaluation of Biodegradation and Osteoinductive Properties of Tantalum and Zinc Co-Doped β-TCP Porous Bioceramic Scaffolds.

Abstract

β-Tricalcium phosphate (β-TCP) ceramics suffer from inadequate mechanical strength and uncontrolled degradation in critical bone defect repair. To address this, Tantalum/Zinc co-doped β-TCP （Ta/Zn-β-TCP） porous ceramics are developed via a novel microwave-ultrasound hydrothermal method. Physicochemical analyses confirms successful incorporation of Ta⁵⁺ (2.46 mol%) and Zn²⁺ (2.35 mol%) into the β-TCP lattice without phase alteration, inducing bidirectional lattice distortion that enhances compressive strength by 90% (10.72 ± 0.31 MPa and pure β-TCP: 5.65 ± 0.20 MPa) while maintaining optimal porosity (63.7 ± 1.2%). In vitro, Ta⁵⁺ formed a passivation layer regulating Ca²⁺ release (degradation rate: 5.96% at 28 days and 9.8% for pure β-TCP), while Zn²⁺ enriched PO₄ ^3- ions to accelerate biomimetic mineralization. The co-doped ceramic significantly upregulates osteogenic genes (Runx2: ↑180%, BMP2: ↑230%, OCN: ↑190%) in rat bone marrow mesenchymal stem cells (rBMSCs. In a rat calvarial critical-sized defect model, micro-CT and histology revealed superior bone regeneration with Ta/Zn-β-TCP (BV/TV: 45.98% at 12 weeks), outperforming pure β-TCP (22.27%) and commercial Novabone (45S5 bioglass-based) (41.67%). The material's triple synergy mechanical reinforcement, immunomodulation, and coupled angiogenesis-osteogenesis, establishes it as a promising candidate for non-load bearing bone repair.