Carbonated hydroxyapatite deposition at physiological temperature on ordered titanium oxide nanotubes using pulsed electrochemistry

The effect of temperature and nanotubular surface morphology on calcium phosphate deposition was investigated using a modified simulated body fluid and electrochemistry. Ordered nanotubular titanium oxide plates were coated by pulsed electrochemical deposition process, while titanium oxide and pure titanium surfaces were used as controls at 80 °C and 37 °C. The calcium phosphate deposit was characterized using XRD, FT-IR and FE-SEM. Carbonated hydroxyapatite was deposited at the physiological temperature of 37 °C on nanotubular surfaces, which provided a large surface area for hydroxide ion generation and a small volume for the confinement and concentration of hydroxide ions. Compounds containing carbonates and hydrogen phosphates were deposited on porous titanium oxide surfaces and flat titanium surfaces as the control group. This study demonstrates deposition of hydroxyapatite at physiological temperatures, which is essential for codeposition of organic bioceramics for medical use.