Synthesis and in-vitro biocompatibility study of bio-functionalized titania nanotubes for dental implants

Full text: Despite commercially pure titanium (cp-Ti)-based dental implants are widely used clinically, a significant number of failures still occur due to poor osseointegration. The modification of Ti features such as nanoscale topography and chemistry seems a good strategy to achieve enhanced bone-implant integration (osseointegration). The main aim of this work was to develop bio-functionalized titania nanotubes (NTs), doped with calcium (Ca) and phosphorous (P) and to study its in-vitro biocompatibility. Hence, Ca and P-doped NTs (Ca/P-NTs) were synthesized by two-step anodization process. Firstly, NTs were grown on Ti substrates by anodizing at 60V for 30min. in an electrolyte containing ethylene glycol, 0.3wt.% NH₄F and 3vol.% H₂O. Then, NT surfaces were anodically treated at 100V for 30min. in an electrolyte composed of calcium acetate and β-glycerophosphate. The surfaces were characterized by Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Water Contact Angle (WCA) measurements. The viability of MG63 cells was evaluated by MTT assay and the adhesion ability was studied by fluorescence microscopy and FESEM. One-Way ANOVA was used to determine statistical significance. Results showed that well-ordered Ca/P-NTs with 74.5±13.2 nm diameter and 13±1.1 μm length were synthesized. Chemical analysis of such NTs confirmed the presence of Ca and P. After two-step anodization, the hydrophilicity of Ti was enhanced as shown by the significant decrease of WCA from 45.4±3.1 deg to 14.1±1.3 deg (Ti vs. Ca/P-NTs; p<0.001). MG63 cells cultured on Ca/P-NTs showed similar biocompatibility behavior as cultured on NT surfaces. Osteoblastic cells were well-adhered presenting an elongated morphology with filopodia forming adhesion points with NTs. The Ca and P content appear to influence the cell viability/proliferation and adhesion ability. These are novel and promising surfaces for dental implants since they influence cell functions showing potential to improve osseointegration. (author)