Investigating the early osteogenic potential of strontium doped titanium alloy surface

The current study was conducted to test the early osteogenic potential of strontium (Sr) doped titanium-aluminum-vanadium (Ti-6Al-4V) alloy using an in vitro cell culture experiment. Thirty Ti-6Al-4V alloy sheets were sandblasted and etched with large grit acid. Of these, 10 alloy sheets represented group I, 10 sheets doped with Sr using a hydrothermal process represented group II, and 10 sheets also coated with Sr-supplemented hydroxyapatite using a hydrothermal process represented group III. The surfaces of the three groups were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The three groups were also compared in terms of their water contact angle, protein adsorption, and Sr ion release profile. Further, bone marrow mesenchymal cells (BMSCs) obtained from the femora of 10 Sprague Dawley rats were used for the in vitro cell culture experiment, and the viability of the cultured cells was evaluated using the MTT assay and confocal microscopy; in addition, their osteogenic potential was assessed using alkaline phosphatase ALP activity. For statistical analysis, data were analyzed using one-way analysis of variance (ANOVA; IBM SPSS statistics 23), and p < 0.05 was considered statistically significant. SEM images revealed that the three groups had surface roughness, and EDS and XRD revealed the success of incorporating Sr to their surfaces. Group III had the best contact angle, protein adsorption, and Sr ion release rate. The cell culture also revealed that the surfaces of the titanium alloy sheets in group III were the most viable and had the best osteogenic potential; however, there was no statistically significant difference between groups I and II. In Conclusion, Sr alone was not able to improve the osteogenic potential of titanium alloy surfaces.