Boosting synergistic osteogenic and antibacterial effects by constructing ZnO nanoparticle-doped hetero-polyelectrolyte multilayer coatings

The long-term success of titanium implants is often limited by poor osseointegration and implant-associated infections. Here, a multifunctional zinc-containing polyelectrolyte multilayer coating was fabricated on titanium substrates via a layer-by-layer assembly method. The coating, composed of polyethylenimine, polymethacrylic acid, ZnO nanoparticles, and rhBMP-2, enabled the synergistic and sustained release of Zn 2+ and rhBMP-2. Characterization confirmed a uniform structure, enhanced hydrophilicity, and stable interlayer bonding. The optimized ZnO concentration maintained Zn 2+ release within a cytocompatible range, promoting cell proliferation and osteogenic differentiation. Moreover, the coating exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli . In vivo studies revealed good biosafety, improved bone regeneration, and a more favorable local microenvironment. This study presents a practical surface modification strategy for titanium implants, achieving synergistic antibacterial and osteogenic effects with potential for long-term clinical application.