Engineering tunable dual peptide hybrid coatings promote osseointegration of implants

Utilizing complementary bioactive peptides is a promising surface engineering strategy for bone regeneration on osteogenesis. In this study, we designed block peptides, (Lysine)₆-capped RGD (K₆-(linker-RGD)₃) and OGP (K₆-linker-(YGFGG)₂), which were mildly grafted onto PC/Fe-MPNs through supramolecular interactions between K₆ and PC residues on the MPNs surface to form a dual peptide coating, named PC/Fe@K₆-RGD/OGP. The properties of the block peptides coating, including mechanics, hydrophilicity, chemical composition, etc., were detailly characterized by various techniques (ellipsometry, quartz crystal microbalance, X-ray photoelectron spectroscopy, water contact angle, scanning electronic microscopy and atomic force microscopy). Importantly, the RGD/OGP ratio can be well adjusted, which allowed optimizing the RGD/OGP ratio to endow significantly enhanced osteogenic activity of MC3T3-E1 cells through the Wnt/β-catenin pathway, while also promoting cell adhesion, immune regulation, inhibiting osteoclast differentiation and oxidative stress reduction. In vivo, the optimized RGD/OGP coatings promoted bone regeneration and osseointegration around implants in rats with bone defects. In conclusion, rationally designed PC/Fe@K₆-RGD/OGP coating integrated RGD and OGP bioactivities, providing a convenient approach to enhance bioinert implant surfaces for bone regeneration.