Development of Hydroxyapatite Coating on Titanium Alloy for Orthopedic Applications

Abstract

Titanium and its alloys have long been employed in biomedical applications due to its remarkable features, such as good bio-compatibility, resistance to bodily fluid effects, tremendous tensile strength, flexibility, and high corrosion resistance. If these materials are used as bio-implant, it releases toxic ions like aluminium and vanadium in the body fluid environment after implantation to overcome the problem Ti-6Al-4V alloy was coated with hydroxyapatite (HAp) which provides better bioactivity, osteocompatibility, and antibacterial activity. The present work is to synthesize HAp from snail shells using a simple wet precipitation method. The prepared SHAp was coated on the Ti-6Al-4V alloy using electro-deposition method. The coated alloy was characterized by various techniques such as FTIR, XRD, FESEM, EDAX, AFM and antibacterial activity. The spherical like structures was observed on the coated metal surface using FESEM. The potentiodynamic polarization study indicate that the breakdown potential (Eb) and repassivation potential (Ep) of uncoated sample was found to be 175.5 mV and −105.1 mV and for the coated sample was noticed at 357.2 mV and −50.2 mV respectively. The potential shift was moving towards the noble direction and it controls the rate of corrosion on coated Ti-6Al-4V. The zone of inhibition values were found to be 11.0 ± 0.45 mm for gram negative bacteria and 8.2 ± 0.28 mm for gram positive bacteria which was confirmed by the antibacterial activity study. The anti-bacterial activity of SHAp coated Ti-6Al-4V was superior to E. coli than Staphylococcus aureus. It is concluded that SHAp coated Ti-6Al-4V alloy may be considered a better material for orthopedic applications.