Enhancement of Corrosion Resistance and Biological Performances of Cu-Incorporated Hydroxyapatite/TiO<sub>2</sub> Coating by Adjusting Cu Chemical Configuration and Hydroxyapatite Contents
Xinxin Zhang, Xueqin Lü, You Lv, Lei Yang, Erlin Zhang, Zehua Dong
Abstract
To simultaneously enhance the antibacterial efficacy and cell biocompatibility of titanium (Ti)-based orthopedic implants, Cu-incorporated hydroxyapatite (HA)/TiO2 coatings have been fabricated via the micro-arc oxidation method in an aqueous solution containing calcium lactate ((CH3CHOHCOO)2Ca) and sodium dihydrogen phosphate (NaH2PO4) along with different contents of ethylenediaminetetraacetic acid copper(II) disodium salt (Na2Cu-EDTA). Microstructural characterization reveals that with the addition of 2 g/L of Na2Cu-EDTA, the resultant coating contains uniformly distributed HA phase depositions with a high Cu+-to-Cu2+ ratio relative to those in the electrolytes containing 5 and 10 g/L of Na2Cu-EDTA, which contain reduced amounts of HA depositions with Cu species mainly existing as Cu2+. Further, electrochemical responses and in vitro biological tests were conducted to assess corrosion resistance, antibacterial capability, and cell biocompatibility. It is revealed that the Cu-incorporated HA/TiO2 composite coating produced by 2 g/L of Na2Cu-EDTA exhibits enhanced corrosion resistance, antibacterial capability, and cell biocompatibility relative to those fabricated in the electrolytes containing 5 and 10 g/L of Na2Cu-EDTA, which is mainly attributed to the increased amount of HA components and the chemical configurations of the Cu specie.