Biomimetic Poly(NaSS) Grafted on Ti6Al4V: Effect of Pre-adsorbed Selected Proteins on the MC3T3-E1 Osteoblastic Development

Titanium alloy Ti6Al4V has been extensively used in biomedical applications as implants and prostheses with successful results. In order to improve its long term performance in vivo, a bioactive polymer, poly(sodium styrene sulfonate) (poly(NaSS)), was chemically grafted onto its surface. The chemical characterization of poly(NaSS) grafted Ti6Al4V materials was performed by ATR-FTIR, XPS and toluidine blue colorimetric assay highlighting the presence of sulfonate groups. The poly(NaSS) grafting led to a significant increase in the hydrophilicity of the surface (contact angle and surface energy) as well as a strong improvement of the osteoblast cells response.

Proteins play a major role in the interactions between cells and surfaces since adsorbed proteins may modify the cell signaling process. The influence of three proteins - fibronectin (Fn), collagen I (Col I) and albumin (BSA) - involved in osteoblast cell response was studied on ungrafted and grafted surfaces. The osteoblastic cell behavior, differentiation and development/maturation was followed. Fn and Col I tend to facilitate cell adhesion and interactions with the surfaces, respectively in terms of quantity (proliferation) and cell spreading. This result was intensified in the presence of NaSS groups. The pre-adsorption of Col I on grafted surfaces was also associated with significant improvements on the osteoblastic early differentiation (higher alkaline phosphatase activity) compared to the rest of the tested groups.

Generally, it was seen that the poly(NaSS) grafting process on titanium based surfaces instigates osteoblastic development.