Multifunctional poly(2-methoxyethyl acrylate) coatings with intermediate water on titanium implants enhance...

Robust, rapid osseointegration is critical for the success of orthopaedic and dental implants, yet it remains challenging, particularly in patients with compromised bone quality. Although many surface modifications have shown promise, no polymer-based strategies have achieved widespread clinical adoption. Moreover, the roles of hematoma formation and thrombosis at bone regeneration sites in subsequent osteogenesis remain controversial, and the effects of antithrombogenic surface modifications on bone formation are poorly understood. Herein, poly(2-methoxyethyl acrylate) (PMEA), a bifunctional polymer that couples blood compatibility with permissisve cell adhesion, was coated onto titanium implants. Upon hydration, PMEA forms an "intermediate water" state at the interface, which provides excellent blood compatibility while allowing adherent cell attachment. The performance of PMEA-coated substrates is compared with that of uncoated controls and a reference polymer coating with minimal intermediate water. In vitro, PMEA altered early cell adhesion and upregulated osteogenic genes, significantly promoting osteoblast differentiation. Alkaline phosphatase activity and other osteogenic markers increased significantly compared with uncoated controls, while intrinsic antithrombotic properties of the titanium surface were preserved. In a rat femoral implantation model, PMEA-coated titanium implants achieved significantly greater bone-implant mechanical fixation strength than controls throughout the post-implantation period. Histology studies demonstrated accelerated bone maturation, increased lamellar bone formation, reduced disorganized woven bone, and more continuous bone-implant contact around PMEA-coated implants. Collectively, these results indicate that PMEA functions as a trifunctional implant coating that integrates blood compatibility, tissue compatibility, and bone affinity, and thus provides a practical multifunctional surface design strategy to improve early osseointegration.