Abstract: PURPOSE: To fabricate micro-nano titanium phosphate coating on the surface of titanium (Ti) material to promote osseointegration. METHODS: Through the hydrothermal reaction of phosphoric acid under specific conditions, a Ti sheet/cylinder with a coating of micro-nano titanium phosphate, namely micro/nanorod Ti (P-R-Ti), was prepared. The control group was untreated smooth pure Ti (cp-Ti). The materials were characterized and analyzed in terms of composition, morphology, hydrophilicity, etc., and the cell proliferation activity was tested in vitro. The changes in protein and gene expression related to cell adhesion and differentiation were analyzed to explore the effect of P-R-Ti on the biological behavior of rat bone marrow mesenchymal stem cells (BMSCs). At the same time, the effects of P-R-Ti on bone union were evaluated 12 weeks after implantation into rat tibia, and its biomechanical strength was tested.SPSS 21.0 software package was used for data analysis. RESULTS: The material characterization showed that the surface of P-R-Ti had a dense micro nano rod structure. In vitro experiments showed that the expression of adhesion related proteins and mRNA in P-R-Ti group was up-regulated, and the cell viability was significantly enhanced. The expression levels of ALP activity, Runx-2, Col-1, OPN, OCN mRNA in P-R-Ti group were significantly higher than those in cp Ti group. In vivo experiments showed that the bone area ratio and the contact between bone and implant in P-R-Ti group were significantly higher than those in cp-Ti group. The maximum pushing force was(179.3±11.3)N, and the ultimate shear strength was (19.25±1.85)N/mm². CONCLUSIONS: P-R-Ti can effectively promote the osseointegration of titanium material. It is expected to be used as an excellent method of titanium surface modification for clinical application.

Key words: Micro/nano interface, Osseointegration, Implant, Titanium phosphate