Electrochemical deposition of a biofunctionalised silver and strontium substituted hydroxyapatite nanocomposite coating on a β-type titanium alloy

ABSTRACT As a result of hydroxyapatite’s (HAp) similarity to the mineral component of bone, it has been extensively investigated for biomedical application. To mimic the non-stoichiometric hydroxyapatite of bone or add positive features to it, different cationic and anionic substitutions have been studied. In this study, the nanocomposite coating of strontium (Sr) and silver (Ag) substituted HAp was deposited on a rarely investigated β type titanium alloy with low Young’s modulus to investigate its morphological and chemical features, crystallographic structure, thickness, biocompatibility, and hydrophilicity. The coating was deposited via a little reported electrochemical method which has the advantages of both electrolytic and electrophoretic deposition. The process is simple and can be conducted under mild experimental conditions to prevent potential high-temperature induced-thermal stress complications. The chemical, morphological and crystallographic features were characterised using EDAX, FE-SEM, and XRD analysis. The coating thickness was measured using a profilometry test. The biocompatibility and wetting behaviour were evaluated by MTT assay and the sessile drop technique, respectively. The coatings have shown rod-shaped, homogenous, and nano-sized HAp particles, with a close Ca/P ratio to stoichiometric apatite; meanwhile, Sr and Ag nanosphere particles are capable of modifying its surface. The coating can support cell growth and proliferation and shows a superhydrophilic surface.