Precipitation of bone-like apatite on anodised titanium in simulated body fluid under UV irradiation

Abstract

Fabricating a photocatalytic oxide layer on biomaterial surfaces has recently attracted a great deal of attention owing to its effect in accelerating the osseointegration process. Anodic oxidation is a widely used electrochemical method to deposit ceramic coatings of photocatalytic titania on titanium metal substrates. The current study aims to investigate the effect of UV irradiation during in vitro testing on the precipitation of bone-like apatite on the anodised surface. High purity titanium foils were anodised with varying voltages (50–350 V) in a mixture of 0.04 M β-glycerophosphate disodium salt pentahydrate (β-GP) and 0.4 M calcium acetate monohydrate (CA) for 10 min. Subsequently, the anodised titanium foils were soaked in simulated body fluid (SBF) for 7 days with illumination under ultraviolet light C. The titanium foil produced using high voltage (350 V) appeared to be highly porous and demonstrated high crystallinity as well high hydrophilic properties. After soaking in SBF for 7 days, highly crystallised bone-like apatite was covered on the surface of anodised titanium. Interestingly, the smooth and partially porous surface of the anodised titanium was observed to be fully covered by the bone-like apatite layer, contradicting previous findings that smooth surfaces lack sufficient nucleation sites needed for the growth of bone-like apatite. The suggested mechanism for the formation of bone-like apatite under UV irradiation is illustrated in this article. The findings of this study indicate that UV irradiation is able to accelerate the formation of bone-like apatite on the surface of titanium.