Electrophoretic, deposition and characterization of composite chitosan-based coatings incorporating bioglass and sol-gel glass particles on the Ti-13Nb-13Zr alloy

Composite bioglass/chitosan and sol-gel glass/chitosan coatings were electrophoretically deposited (EPD) on a near-beta Ti-13Nb-13Zr alloy. The influence of EPD parameters, such as chemical composition and suspension pH as well as potential difference and deposition time, on the uniformity of coatings has been studied. It was found that the pH value of the suspension and chemical composition have a significant impact on the electrokinetic properties of suspended chitosan molecules and glass particles, which in turn affect the deposition rate of EPD and the uniformity of as-deposited coatings. The thicknesses of the bioglass/chitosan and sol-gel glass/chitosan coatings were up to 2 mu m and 860 nm, respectively. The microstructure of the coatings was characterized by scanning and transmission electron microscopy as well as X-ray diffractometry. The coating microstructure was composed of sol-gel glass particles or amorphous bioglass separate particles or agglomerates, homogeneously embedded in an amorphous chitosan matrix. The sol-gel particles consisted of hydroxyapatite (hp), CaSiO3 (tp) phases. The sol-gel glass/chitosan coating exhibited better adhesion to the titanium alloy substrate than the bioglass/chitosan coating. It was found that both types of coating improve the electrochemical corrosion resistance of the Ti-13Nb-13Zr alloy in Ringer's solution and are cytocompatible with osteoblast-like cells. (C) 2017 Elsevier B.V. All rights reserved.