摘要
Given the clinical challenge of implant-associated infections, the development of stimuli-responsive antibacterial surfaces is of great significance for the repair of infected bone defects. In this study, a multifunctional coating of TNT + PMAA with pH-responsive antibacterial and pro-osteogenic activities was designed and fabricated on the surface of orthopedic titanium implants. TiO 2 nanotubes (TNT), as nanocarriers, were first prepared via electrochemical anodization. Subsequently, Zn 2+ ions and naringin were loaded via hydrothermal treatment and spin-coating, respectively. Poly(methacrylic acid) (PMAA), acting as a molecular “gatekeeper”, was further grafted onto the surface via a carbodiimide reaction with pre-deposited polydopamine layers. The as-prepared coatings were systematically characterized in terms of their morphology, chemical composition, surface wettability, Zn 2+ and naringin release behaviors, antibacterial activity, and cytocompatibility. The TNT + PMAA coatings maintained the porous nanotubular structure of the original nanotubes, but the inner diameter was significantly reduced and the roughness increased. Owing to the introduction of abundant hydrophilic groups, the surface wettability was greatly enhanced. The TNT + PMAA coatings intelligently released Zn 2+ ions and naringin to significantly inhibit S . aureus and E . coli . Such release was notably triggered by acidification of the surrounding microenvironment, thus realizing on-demand release. The TNT + PMAA coatings displayed excellent cytocompatibility, which enhanced osteoblast adhesion and proliferation, up-regulated the function expressions of alkaline phosphatase (ALP), osteocalcin (OCN), and runt-related transcription factor-2 (RUNX2), and significantly accelerated the formation of bone-like apatite crystals. This work offers a novel approach for designing osteogenic and antibacterial surfaces for infected bone regeneration and repair, using natural components with low cytotoxicity.
危险品化学品经营许可证（带存储）