Biofunctionalisation of magnesium alloys by successive immobilisation of poly(ethylene glycol), fibronectin and heparin

In the present study, with the aim of improving their corrosion resistance, anticoagulation and cytocompatibility with endothelial cells, a magnesium alloy (AZ31B) was modified by the alkali heat treatment followed by the immobilisation of the dopamine layer. Subsequently, molecules of poly(ethylene glycol) (PEG) and fibronectin or fibronectin–heparin complexes were successively immobilised on the dopamine-modified surface. After the surface modification, the hydrophilicity of magnesium alloy was obviously improved. The corrosion resistance of the magnesium alloy was improved through alkali heat treatment, and the immobilisation of dopamine and PEG can further reduce the corrosion rate. However, the corrosion resistance of the magnesium alloy was slightly reduced by the grafting of fibronectin or fibronectin–heparin complex. Furthermore, the modified samples showed improved hemocompatibility and good cytocompatibility with the endothelial cells on the fibronectin or fibronectin–heparin-modified surfaces. Therefore, the corrosion resistance, anticoagulation and cytocompatibility of the magnesium alloy can be enhanced by alkali heat treatment and subsequent immobilisation of biomolecules. The method of this study can be used for surface modification of magnesium alloys to impart these with better corrosion resistance, blood compatibility and cytocompatibility with endothelial cells simultaneously.