Electrophoretic deposition of biocomposite ceramic coatings of hydroxyapatite and chitosan with silver and gentamicin on titanium for medical applications

Abstract

Biocomposite ceramic coatings hydroxyapatite (HAP), silver/hydroxyapatite (Ag/HAP) and silver/hydroxyapatite/graphene (Ag/HAP/Gr) are obtained on titanium by electrophoretic deposition (EPD). The goal of this research was to develop multifunctional composite coatings as a suitable strategy to improve the surface properties of metallic implants. The deposition was performed on titanium electrodes with specific geometry suitable for implantation in the frontal bone of rabbits for in vivo experiments. The effect of deposition parameters on deposited mass was investigated by varying different values of constant voltage for various deposition time. Uniform and compact HAP coatings were successfully deposited at applied voltage of 30 V for 45 s, whereas Ag/HAP and Ag/HAP/Gr coatings with satisfying adhesion and coverage were deposited at applied voltage of 60 V for 1 min. Bearing in mind certain toxic effects of the nanoparticle silver, the deposition of the coating of hydroxyapatite/chitosan/graphene (HAP/CS/Gr) of the same composition with the addition of the antibiotic gentamicin was performed, in order to replace the silver nanoparticles. The antimicrobial activity of the coating HAP/CS/Gr without and with gentamicin against Staphylococcus aureus and Escherichia coli was examined by agar diffusion test. Moreover, disc diffusion test showed improved bactericidal effect of gentamicin-loaded composite coatings against Staphylococcus aureus and Escherichia coli compared to control non-gentamicin-loaded coatings.