Biological properties of direct grafting by ultraviolet irradiation of vinyl benzyl phosphonic acid onto titanium surfaces

International audienceTitanium (Ti) and its alloys are the most effective metals for structural implantable deviceapplications. However, Ti-based materials are passively integrated into the bone, resulting in a purelymechanical attachment. Consequently, the loss of osseointegration often leads to implant failure. Therefore,enhancing bone formation surrounding the implant is primordial. In previous investigations conducted in ourlaboratory, grafting bioactive polymers with sulfonate groups, such as poly(sodium styrene sulfonate)(polyNaSS), was demonstrated to increase the adherence and differentiation of osteoblast cells. In this context,this contribution proposes to functionalize Ti with a phosphonic acid-based polymer, poly(vinyl benzylphosphonic acid) (poly(VBP)). A two-step UV-initiated grafting polymerization was developed to covalentlygraft VBP into Ti surfaces. The surfaces were characterized using colorimetry, Fourier-transformed infraredspectra recorded in an attenuated total reflection (FTIR-ATR), X-ray photoelectron spectroscopy (XPS)techniques, and water contact angle (WCA) measurements. The Ti substrates were evaluated for cell viability,spreading, alkaline phosphatase activity, and calcium formation using MC3T3-E1 osteoblast cells. Theinteraction of Ti grafted samples with osteoblast cells, was significantly improved as well as the cell/surfaceinteraction. Together, these findings demonstrated that poly(VBP) grafted on Ti surfaces improved osteoblasts'early cell adhesion and spreading activities, crucial for osseointegration applications