Electroactive barium titanate coated titanium scaffold improves osteogenesis and osseointegration with low-intensity pulsed ultrasound for large segmental bone defects

Abstract

For large segmental bone defects, porous titanium scaffolds have some advantages, however, they lack electrical activity which hinders their further use. In this study, a barium titanate (BaTiO ₃) piezoelectric ceramic was used to modify the surface of a porous Ti6Al4V scaffold (pTi), which was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and roughness and water contact angle analyses. Low intensity pulsed ultrasound (LIPUS) was applied in vitro and in vivo study. The activity of bone marrow mesenchymal stem cells, including adhesion, proliferation, and gene expression, was significantly superior in the BaTiO ₃/pTi, pTi + LIPUS, and BaTiO ₃/pTi + LIPUS groups than in the pTi group. The activity was also higher in the BaTiO ₃/pTi + LIPUS group than in the BaTiO ₃/pTi and pTi + LIPUS groups. Additionally, micro-computed tomography, the mineral apposition rate, histomorphology, and the peak pull-out load showed that these scaffold conditions significantly enhanced osteogenesis and osseointegration 6 and 12 weeks after implantation in large segmental bone defects in the radius of rabbits compared with those resulting from the pTi condition. Consequently, the improved osteogenesis and osseointegration make the BaTiO ₃/pTi + LIPUS a promising method to promote bone regeneration in large segmental bone defects for clinical application.

Graphical abstract

Highlights

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  BaTiO ₃ coating was successfully fabricated by a wet chemical method on the surface of porous Ti6Al4V scaffolds.

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  BaTiO ₃ coating showed better surface hydrophilicity and roughness than pure porous Ti6Al4V scaffolds.

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  BaTiO ₃ coating improved the biological behavior of BMSCs in vitro and promoted the formation of new bones in vivo.

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  LIPUS activated piezoelectric effect of BaTiO ₃ coating, enhanced cell viability in vitro and promoted osteogenesis in vivo.

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  BaTiO ₃/pTi + LIPUS conditions showed promising potential as a method to repair long bone defects for clinical application.