Osteoblastic Responses of Sandblasted <scp>TA6V</scp> Femoral Implants Functionalized With Phosphonate Polymers via <scp>UV</scp> ‐Induced Direct Grafting

Most of the orthopedic implants are nowadays manufactured using titanium or titanium alloy materials due to their mechanical properties and good compatibility with human tissues. Still, implant rejections frequently occur and are related to a loss of the osteointegration, which in turn is strongly linked to the implant surface's features. In particular, an increase in the roughness or functionalization with bioactive groups of the surface of a Ti implant demonstrates an enhanced osteointegration. In this study, we analyze the osteointegration of a femoral implant made of Ti alloy (TA6V) with high roughness (≈3.5 μm) and functionalized with polyvinyl benzyl phosphonic acid bioactive polymers (p(VBP)). The TA6V sample surfaces were sandblasted to increase their surface roughness and then followed a two-step UV-induced grating polymerization process to covalently link p(VBP) polymers to their surfaces. The prepared surfaces were characterized at each step using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), water contact angle measurement (WCA), and colorimetry (TB assay). Then, samples were incubated with MC3T3-E1 osteoblast cells, and cell viability, cell morphology, alkaline phosphatase activity, and formed calcium ions were evaluated. Finally, an in vivo study was carried out by integrating the grafted femoral implants in rabbits for 6 and 12 weeks, followed by quantitative ultrasound measurements (QUS) of the bone/implant interface. Successful grafting of p(VBP) is demonstrated on the rough TA6V surfaces, and in vitro results show an enhanced integration and activity of the osteoblastic cell.