3D printing of a titanium-tantalum Gyroid scaffold with superb elastic admissible strain, bioactivity and in-situ bone regeneration capability

摘要

The simultaneous achievement of admirable mechanical compatibility and osteoinduction in metallic implants can avoid stress shielding and facilitate osseointegration and osteogenesis. Herein, we reported a titaniumtantalum (Ti-Ta) Gyroid scaffold in-situ fabricated with selective laser melting (SLM), a powder-bed-fusion three-dimensional (3D) printing process, enabling superb elastic admissible strain (EAS), bioactivity and insitu bone regeneration capability. The printed scaffold with 90% porosity exhibited a good combination of low elastic modulus (1.8 GPa) and high compressive yield strength (55.5 MPa), resulting in a superb EAS (3.03%) that is suitable for the reconstruction of cancellous bone. The mechanisms of the high EAS were ascribed to the formation of 13(Ti, Ta) solid solution, ultrafine 13 grains accompanying with nanocrystalline alpha' grains, and the existence of dislocations and stacking faults. Bone-like apatite was spontaneously induced on the surface of the printed Ti-Ta alloy due to the generation of self-passivating Ta2O5 film, indicating a good biomineralization ability. Compared to pure Ti, the printed Ti-Ta alloy exhibited enhanced expression of vinculin, earlier cell extension, increased nuclei density, better cell proliferation, and the up-regulated expression of osteogenesis genes. Animal studies further validated that the printed Ti-Ta scaffold was capable to reinforce bone integration and accelerate bone regeneration. These findings provided a promising strategy for treating bone defects through 3D printing of metallic scaffolds.

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