Comparative Study of Sr+2 and Zn+2 Incorporation in the Biomimetic Coating of a Prosthetic Alloy

Abstract

The next great wave of innovation and development for implantable medical devices focuses on surface engineering. This would enhance their performance, restore lost functions and ultimately reduce pain. Biomimetic coating is a promising approach, used in that concern. In the present work, an attempt was made to develop the function of the biomimetic coating rather than the classical biocompatibility. Corrected simulated body fluid, leading the conventional fluid concentration by one half, 1.5 c-SBF, was prepared with adequate supplement of Sr +2 , or Zn +2 according to the permissible therapeutic doses, 0.5 mM. The selection of Sr +2 and Zn +2 as additives was owing to their anti-osteoporotic and antimicrobial/bacterial activity respectively. The bioinert discs of titanium aluminum vanadium alloy, Ti-6Al-4V, were pretreated according to our previously developed protocol [Alaa Adawy et al. 2009, Biomimetic Coating of Precalcified Ti-6Al-4V Alloy, J. Open Medical Devices, 1(2009)19]. Subsequently, they were soaked in the prepared SBFs. Stepwise surface characterization was assessed using Diffuse Reflectance Infra-red Fourier Transform Spectroscopy, DRIFTS. In parallel, the remnants of the soaking solutions were analyzed chemically by atomic absorption and biochemical kits, and physically by AC electrical conductivity measurements at room temperature. Scanning electron microscopy, SEM, was used to assess surface final morphology post the whole treatment duration. Incorporation of Sr +2 and Zn +2 resulted in the growth of calcium deficient apatite of high carbonate content. The former increased the activity of biomimetic deposition while the latter induced more uniformity in the resultant coating.