Fabrication and in vitro biological performance of a double-layered nanoparticles-microarc oxidation composite coating on titanium for dental implant application

Abstract

Sufficient residual alveolar bone volume plays an important role in the success rate and service life of dental implants. However, alveolar bone deficiency is a common clinical phenomenon, and the alveolar bone would be further absorbed by peri-implant infection. Therefore, it is highly desirable to promote peri-implant alveolar bone regeneration and inhibit alveolar bone resorption when the alveolar bone mass is insufficient. For this purpose, a pH-sensitive double-layered nanoparticles-microarc oxidation (MAO) composite coating was fabricated on titanium for dental implant application in this study. The pH-sensitive double-layered nanoparticles were prepared by a poly(L-lactic acid) inner layer and a chitosan outer shell, containing stromal-cell derived factor-1, recombinant human bone morphogenetic protein 2 and osteoprotegerin. The composite coating was fabricated on MAO coating by cross-linking the pH-sensitive double-layered nanoparticles with gelatin. The surface morphology of the composite coating showed that the pH-sensitive double-layered nanoparticles were well distributed and tightly cross-linked in the pores of MAO coating. The composite coating could sustain release the three drugs for more than 30 days. With decreasing pH, the release of osteoprotegerin from the composite coating increased (p < 0.05). In vitro biological studies suggested that the composite coating exhibited no cytotoxicity, and can recruit bone marrow-derived mesenchymal stem cells (BMSCs), promote BMSC differentiation into osteoblasts, and inhibit osteoclast generation. Moreover, with decreasing pH, the inhibitory effect on osteoclast generation was enhanced (p < 0.05). It can be concluded that the fabricated composite coating, which can promote bone regeneration and inhibit bone resorption, has the potential to be applied on the surface of dental implant, especially when the residual alveolar bone is in poor condition.

Keywords

• bone regeneration
• bone resorption
• pH-sensitive
• composite coating
• controlled release