Biomolecular surface coating to enhance orthopaedic tissue healing and integration

Implant osseointegration is a prerequisite for clinical success in orthopaedic and dental applications, many of which are restricted by loosening. Biomaterial surface modification approaches, including calcium-phosphate ceramic coatings and macro/microporosity, have had limited success in promoting integration. To improve osseointegration, titanium surfaces were coated with the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) collagen-mimetic peptide, selectively promoting alpha(2)beta(1) integrin binding, a crucial event for osteoblastic differentiation. Titanium surfaces presenting GFOGER triggered osteoblastic differentiation and mineral deposition in bone marrow stromal cells, leading to enhanced osteoblastic function compared to unmodified titanium. Furthermore, this integrin-targeted coating significantly improved in vivo peri-implant bone regeneration and osseointegration, as characterized by bone-implant contact and mechanical fixation, compared to untreated titanium in a rat cortical bone-implant model. GFOGER-modified implants also significantly enhanced osseointegration compared to surfaces modified with full-length type I collagen, highlighting the importance of presenting specific biofunctional domains within the native ligand. In addition, this biomimetic implant coating is generated using a simple, single-step procedure that readily translates to a clinical environment with minimal processing and cytotoxicity concerns. Therefore, this study establishes a biologically active and clinically relevant implant-coating strategy that enhances bone repair and orthopaedic implant integration. (C) 2007 Published by Elsevier Ltd.