Bioinspired Amine-Guided Polyphenol Coatings for Selective Bacterial Disruption and Osseointegration on Orthopedic Implants

Implant-related infections and inadequate osseointegration pose significant challenges in orthopedic surgery. However, current surface modification strategies are generally complex or necessitate harsh synthesis conditions, thereby limiting their versatility. We developed a facile, one-step method to fabricate a stable polyphenol-based coating on titanium using amine-directed self-polymerization. Amine forms covalent bonds with polyphenol, enhancing the coating stability, as confirmed by molecular dynamics simulations. This bioinspired coating eliminated over 90% of Staphylococcus aureus and Escherichia coli by disrupting bacterial chemotaxis and FTSI protein expression of the cell wall, thereby impairing bacterial respiration and interfering with proton and electron transfer in bacterial membranes, which could selectively eliminate pathogenic bacteria through a contact-killing mechanism without any negative effect on mammalian cells. It also promoted the growth and differentiation of bone mesenchymal cells via the Wnt/β-catenin pathway. Additionally, The bioinspired coating modulated macrophages toward a pro-repair M2 polarization. In cell-bacteria competitive coculture experiments, the coating exhibited superior antibacterial efficacy. In vivo studies demonstrate a 50% improvement in osseointegration in infected bone models. This approach is versatile and can be applied to various implant materials, offering a scalable solution for next-generation medical devices.