Evaluation of the in vitro bioactivity of chitosan/Bioglass®/TiO2 composite coatings

Abstract

Since the discovery of Bioglass®, a large number of ceramic materials have been investigated for potential use in the field of tissue engineering. The ability of bioactive materials to bind to bone tissue through the formation of a crystalline hydroxyapatite layer upon contact with simulated or real physiological fluids is well known in this field. In the area of bioactive materials, composite coatings represent a very attractive option to promote functional properties different from those of individual materials. In order to obtain composite coatings with high bioactivity, chitosan/Bioglass®/TiO2 coatings were fabricated by electrophoretic deposition (EPD). A series of experiments were developed to optimise the quality of the EPD deposited films taking into account the density and adhesion of the deposits to the substrate, including the evaluation of parameters such as deposition time, applied voltage, pH of the suspension, and conductivity. Subsequently, the obtained deposits were immersed in simulated physiological fluid (SBF) at pH 7.25 and a temperature of 37ºC for a period of 14 and 21 days. The microstructural changes generated during the reaction on the surface of the composite material were characterised using scanning electron microscopy (SEM).

According to the results obtained in the present work, the formation of a dense and homogeneous layer of crystalline hydroxyapatite on the surface of all the composite deposits obtained was demonstrated. The results obtained indicate that composite materials made from chitosan and Bioglass® are highly potential materials for bone tissue regeneration.