Dual action antibacterial TiO2 nanotubes incorporated with silver nanoparticles and coated with a quaternary ammonium salt (QAS)

To exploit titanium implants with long-term antibacterial property, TiO2 nanotubes were firstly generated onto titanium substrates via an anodization method, silver nanoparticles were then formed in situ within the TiO2 nanotubes and a quaternary ammonium salt (QAS, 3-trimethoxysily-propyldimethyloctadecyl-ammonium chloride) was immobilized onto TiO2 nanotubes. The successful construction of the antibacterial TiO2 nanotubes was revealed by field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), thin-film X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and contact angle measurements, respectively. The antibacterial property of the prepared substrates was determined using zone of inhibition (ZoI) and antibacterial rates of Escherichia coli (E. coli). The cytotoxicity of the substrates was evaluated with osteoblasts in vitro. The Ag nanoparticle loaded and QAS coated TiO2 nanotube substrates (TiO2 nanotube-Ag-QAS) demonstrated long-term antibacterial effect. Moreover, TiO2 nanotube-Ag-QAS substrates displayed good biocompatibility. The study presented a promising approach to fabricate antibacterial titanium-based implants for orthopedic application.