Synergistic Effects of ZrO₂ and MWCNT Duplex Coatings on TiO₂ Nanotube Arrays for Enhanced Osteogenic, Mechanical, and Antibacterial Properties.

Abstract

Electrochemically prepared self-organized titanium nanotube arrays have emerged as a platform of considerable interest owing to their unique structural and functional attributes, driving advances across energy, photocatalytic, and biomedical fields. Their potential as one-dimensional biomaterials have sparked intensive research focused on their controlled fabrication, properties, surface modification, and integration into advanced biomedical technologies. Herein, zirconium dioxide and multi-walled carbon nanotubes coated titanium nanotube arrays heterostructures were fabricated using different electrolytic combinations (organic electrolyte and water-based electrolyte). Zirconium dioxide coating contributes to enhanced chemical stability and mechanical strength. In parallel, the incorporation of multi-walled carbon nanotubes not only offers increased electrical conductivity and promotes cellular interactions, facilitating osteogenic cell adhesion and proliferation, but also promotes mechanical reinforcement and antibacterial efficacy. Comprehensive physical characterizations, including X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier-transform infrared spectroscopy, confirmed successful deposition and morphological uniformity of the duplex coating. In vitro biocompatibility tests using MG-63 osteoblast-like cells demonstrated excellent cytocompatibility, cell adhesion and proliferation. Additionally, water contact angle measurements and nanoscale roughness evaluations revealed considerable surface wettability and superior topography, conducive to osteogenic differentiation. These findings highlight a scalable, chemically stable, and biologically active surface strategy that poses the duplex-coated heterostructure as a next-generation platform for load-bearing implants in bone tissue engineering and regenerative medicine.