Impact of Silica Concentration on the Calcium Phosphate-Based Composite Coatings Prepared by Pulsed Co-Electrodeposition

In this study, calcium phosphate/nano silica (CaP/SiO₂) composite coatings with different concentrations of silica were developed on the pretreated titanium using pulsed co-electrodeposition to improve their biocompatibility. The scanning electron microscopy images showed that silica nano-particles could act as nucleators for the CaP crystals during electrodeposition; therefore, all composite coatings showed different morphologies, in comparison with the pure CaP one. Increasing the concentration of silica particles in bath to 1 g/L changed the morphology of the composite coatings from the clove-like structure to the sunflower-like one. Next, the composite coating obtained from the bath containing 1 g/L silica revealed poor coverability, and some uncoated areas were found on the surface of the pretreated titanium substrate. In addition, the results of cell culture test demonstrated that the coated areas were more biocompatible so that the fibroblast cells were only adhered onto the areas covered with the CaP-based coating.