Presence of sulfonate groups on Ti6Al4V surfaces enhances osteoblastic attachment strength at the interface

The application of the titanium alloy Ti6Al4V in the biomedical field is not new. It has been used for more than 50 years with excellent results. Nonetheless, the interactions developed at the interface biomaterial-cell still present some challenges during implantation. The use of bioactive polymers bearing anionic groups in combination with titanium-based materials has been shown to be an excellent solution. In this study, we demonstrated the impact of the poly(sodium styrene sulfonate) (or poly(NaSS)) chemical grafting on Ti6Al4V surfaces by following the attachment strength of the osteoblastic cells MC3T3-E1, in their initial moments of interaction, and by afterward examine their differentiation. The grafting process was proved to be successful by measuring the poly(NaSS) concentration on the Ti6Al4V using the toluidine blue colorimetric method. The cells morphology was observed without changes being detected between substrates. On the other hand, the presence of the sulfonate groups enhanced the strength of the cellular bond, enabling the MC3T3-E1 to resist to shear stress of 10 dyn/cm2 of magnitude. The poly(NaSS) was found to enhance the osteoblastic cells differentiation by increasing the alkaline phosphatase concentration and, consequently, the cells metabolic activity. This in vitro study proved once again the poly(NaSS) to be suitable for biomedical applications.