Bioactive HA/TiO2 coating on magnesium alloy for biomedical applications

Magnesium alloys are new class of biodegradable alloys having many favourable properties to overcome the limitations of currently used biomedical alloys. Recently, several coatings have been developed to overcome their higher degradation rate. In this regard, a new attempt has been made to develop Hydroxyapatite and Hydroxyapatite/TiO2 coatings on magnesium alloys to increase the biocompatibility and reduce the corrosion rate. The coated surfaces were characterized by Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) Spectroscopy, Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). Contact angle measurements proved higher hydrophilic nature of HA/TiO2 coating compared to HA coating. In-vitro studies showed that HA–TiO2 coated alloy exhibited higher osteoinduction compared to HA coated alloy. Hydrogen evolution studies and corrosion studies confirmed greater reduction in degradation rate of HA/TiO2 coated alloy. Vickers microhardness test also showed enhancement in mechanical strength of the composite coated alloy compared to HA coated alloy. Three point bend test depicted better adherence of the HA/TiO2 coating compared to HA coating on the substrate. Cell culture studies proved higher cell attachment and proliferation on composite coated alloy by controlling the release of magnesium ions into the surrounding body tissue.