In vivo assessment of the osteointegrative potential of phosphatidylserine-based coatings

The successful implantation of titanium-based implants for orthopaedic and dental applications is often hindered because of their mobility, which arises because of a lack of direct binding of the metal surface to the mineral phase of the surrounding bone. Ceramic coatings, although ensuring the integration of the implant within the tissue, are unstable and carry risks of delamination and of failure. Recently, a novel biomimetic approach has been developed where porous titanium implants are coated with calcium-binding phospholipids able to catalyse the nucleation of discrete apatite crystals after only 30 min incubation in simulated body fluids. The present work assesses the osteointegrative potential of this new class of coatings in an in vivo rabbit model and compares its performance with those of bare porous titanium and hydroxyapatite-coated titanium. The data obtained show that phosphatidylserine- based coatings, whilst resorbing, drive the growing bone into apposition with the metal surface. This is in contrast to the case of bare titanium.