Polydopamine coatings embedded with silver nanoparticles on nanostructured titania for long-lasting antibacterial effect

Abstract

Although silver (Ag)-containing biomaterials have been considered as an effective way to prevent bacteria-induced implant infection, the sustaining and long-lasting release of Ag modified on the coating layer remains a problem for the clinical application. Herein, we designed a polydopamine coating with silver nanoparticles on TiO2 nanotube arrays (Ag-PDA-TiO2) by a series of treatment of electrochemical anodization, self-polymerization of dopamine, and the following reduction reaction between PDA and Ag ions. In the system, Ag nanoparticles were synthesized in situ through the reduction action of polydopamine on the surface of anodized titanium oxide nanotube array and PDA was used as reduction and adhesive agent simultaneously. The substrate of PDA coating with silver nanoparticles on titanium surface (Ag-PDA-Ti) and silver nanoparticles prepared by ultraviolet irradiation on TiO2 nanotube array (Ag-TiO2 (UV)) were used as control samples. The morphology, component and wettability of the coating were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and water contact angle analysis. The release rate of Ag of Ag-PDA-TiO2 was slow down due to the adhesion strength of PDA to Ag nanoparticles and the storage capacity of nanotubes. The antibacterial effect of Ag-PDA-TiO2 to E. coli lasted for 14days which is obviously longer than Ag-PDA-Ti and Ag-TiO2 (UV). The method used here could be an effective strategy to prevent implant-associated infection showing significant meaning in clinical application.