HYDROXYAPATITE/CHITOSAN COMPOSITE COATINGS ON TITANIUM SURFACES BY PULSED ELECTROCHEMICAL DEPOSITION

Abstract

A pulsed electrochemical deposition(ED) method was employed to produce hydroxyapatite(HA)/chitosan(CS) composite coatings on Ti substrates.HA dispersed uniformly in the CS network.There was nano-scale hybridization between HA and CS due to in situ co-precipitation.ED was conducted in the cell that had three electrodes:a Ti plate as the working electrode,a platinum plate as the counter electrode and a saturated calomel electrode(SCE) as the reference electrode.Electrolytes were aqueous solution of 5 mmol/L Ca(NO3)2,3 mmol/L(NH4)2HPO4 and CS aqueous solutions with different concentrations(0.17 g/L,0.33 g/L,0.67 g/L).The coatings were prepared under constant voltage and pulsed voltage modes.The experiment results indicated that the pulsed voltage mode can improve the CS content in the coatings and obtain uniform coatings,compared with the constant voltage mode.The pulsed voltage mode also promoted the interaction between Ca and CS according to XPS analysis.Pulsed voltage affected the morphology of the coatings and improved the efficiency of the deposition.The suitable pulsed voltage was-1.3 V.The concentration of CS in the electrolyte affected the CS content in the coatings and the efficiency of the deposition.The suitable concentration was 33.1 g/L.The antibacterial test indicated that HA/CS coatings had good bactericidal ability.Osteoblasts were cultured on the coatings to evaluate the biocompatibility of coatings and the results indicated that the composite coatings favored the attachment and proliferation of the osteoblasts.The results of present study provided valuable references for the further research in developing composite coatings for biomedical applications.