Enhanced wear resistance, antibacterial performance, and biocompatibility using nanotubes containing nano-Ag and bioceramics in vitro

Abstract

An ideal Ti-based implant should avoid stress shielding surrounding the implants, besides a requirement of bioactivity. To achieve the requirements, Ti-35Nb-2Ta-3Zr (wt.%) alloy with a low elastic modulus was used as the substrate for the coatings to avoid stress shielding. The study constructed the micro/nano functional coatings containing bioceramics and Ag ion onto TiO2 nanotubes by anodization, deposition and spin-coating methods. The tribocorrosion behavior, corrosion behavior, antibacterial activity and early osteogenic behavior of bioceramics (nano β-TCP, micro-HA and meso-CaSiO3) and Ag nanoparticles coated on TiO2 nanotubes in vitro were studied. Tribocorrosion and corrosion results exhibit the wear rate and corrosive rate was highly dependent on surface feature. The micro-structure could reduce wear tracks due to adhesive wear and abrasive wear. Compared with other scale structures, the nano-structured passive film showed higher density to prevent solution from corroding substrate. The meso-CaSiO3 was favorable to the cell adhesion, proliferation and early differentiation. It is demonstrated that Si and P enhanced osteogenic response due to the micro/nano structure and ion releasing. Besides, the micro/nano coatings containing Ag ion exhibit great antibacterial capacity against E. coli. The findings indicated that hybrid coating can be a potential coating to accelerate osteogenesis process for orthopedic implants in clinic.