Biofunctionalization of Mg implants with gadolinium coating for bone regeneration

Abstract

Magnesium (Mg) alloys are biodegradable and biocompatible in nature, hence used as bio-implants. Mg alloys possess favourable mechanical properties same as that of human bone. In this work, we demonstrate a simple strategy of formulating a gadolinium conversion coating (GCC) on a biodegradable AZ31 Mg implant that effectively diminishes the corrosion rate and enhances bone formation. AZ31 Mg alloys were immersed in gadolinium nitrate solution at different durations (5, 15, 30, 45 and 60 min) and labeled as GCC-5, GCC-15, GCC-30, GCC-45 and GCC-60 to fabricated gadolinium conversion coating (GCC) on AZ31 Mg alloys. The rapid degradation of AZ31 Mg alloy was reduced by GCC. The surface morphological analysis with the Scanning Electron Microscope (SEM) showed that the vertically arranged cross-linked nanolamellar plates were grown on the AZ31 Mg alloy surface. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results evident that the GCC consists of magnesium oxide and gadolinium oxide were present in the crystalline state. The in-vitro biomineralization of the GCC was analyzed by immersing in simulated body fluid (SBF) solution for 7 days and confirms the formation of nanoglobular hydroxyapatite. The cell culture studies showed an increase in the cell numbers than the bare.