2022, Vol. 26 ›› Issue (4): 546-552

Preparation and characterization of tantalum functional coating on titanium implant

Chen Shuo1, Xiao Dongqin1, Li Xingping1, 2, Ran Bin1, 3, Shi Feng4, Zhang Chengdong1, Deng Li1, Huang Nanxiang1, Liu Kang1, Feng Gang1, Duan Ke3   

Abstract: BACKGROUND: Titanium (Ti) alloy is widely used in clinical orthopedics, because of its good biocompatibility. However, as a biological inert material, it is lack of osteoinductive activity, which is easy to cause implant loosening. Therefore, it is necessary to modify the surface of titanium implant for enhancing its osteogenic activity.
OBJECTIVE: To prepare Tantalum (Ta) functional coating on titanium surface by sol-gel method, and characterize the physicochemical properties and osteogenic properties of the coating.
METHODS: Ta functional coating was prepared on the surface of medical Ti sheet by sol-gel method (named as Ti-Ta). The surface morphology and element composition of the coatings were characterized by scanning electron microscope and energy spectrum analysis. The surface hydrophilicity of Ti sheet, Ta sheet, and Ti-Ta coatings was evaluated by contact angle test. Rabbit bone marrow mesenchymal stem cells were co-cultured with the Ti, Ta and Ti-Ta samples. Cell adhesion morphology on the material surface was observed by scanning electron microscope. Cell adhesion and survival were observed by fluorescence staining. Cell proliferation activity was detected by CCK-8 method. Alkaline phosphatase staining and alizarin red S staining were used to evaluate the osteogenic differentiation ability of cells on the material surface.
RESULTS AND CONCLUSION: (1) Scanning electron microscope images showed that nanoparticles were uniformly distributed on the surface of Ti-Ta sample and no cracks appeared. The elemental analysis showed that elements on the coating were mainly composed of Ta, O, Ti. Ti-Ta surface had better hydrophilicity than that of Ti and Ta. (2) Twelve hours after seeding, cells spread and adhered to the surface of Ti-Ta, protruding a large number of filamentous pseudopodia to the distance and connecting with adjacent cells. For cells on the surface of Ti and Ta, they showed long fusiform shapes, with a small amount of filamentous pseudopodia extending around. (3) The fluorescence staining results of living/dead cells showed that at 72 hours after seeding, a large number of living cells were observed on all surfaces. The number of adherent cells was more than that of Ti sheet and Ta sheet, and the number of living cells on the surface of Ti-Ta coating was more than that on Ti sheet and Ta sheet (P < 0.05). (4) CCK-8 results showed that Ti-Ta had the strongest ability to promote cell proliferation                (P < 0.05). (5) The content of alkaline phosphatase and the number of calcium nodules on the surface of Ti-Ta surfaces were much higher than those on the Ti and Ta surfaces. (6) In conclusion, the Ti surface modified by Ta coating was more favorable for the adhesion and osteogenic differentiation of bone marrow mesenchymal stem cells.

Key words:bone, implant, titanium alloy, tantalum coating, sol-gel method, osteogenic properties, cell adhesion