Tayloring Surface Properties of Rare Earth Magnesium Alloy for Biomedical Application Induced by Laser Processing

摘要

Magnesium alloy has attracted much attention as biodegradable material for medical devices in recent years. However, poor corrosion resistance is the main problem to limit practical applications. High degradation rate will cause fast increase in pH, while the large release of ions into the medium can lead to cytotoxicity. In this work, we demonstrate the capability of laser surface modification for corrosion resistance of Mg-Gd-Ca alloy to avoid rapid degradation, which helps to enhance the bio-compatibility. Microstructure of both as-received surface and laser-modified surface were analyzed carefully by Scanning Electron Microscopy and X-ray Diffraction. Electrochemical corrosion be-havior and immersion test was investigated in order to examine the degradable behavior of laser-modified Mg-Gd-Ca alloy. The enhanced corrosion resistance was found to be caused by the com-bined effect of secondary phase dissolution and galvanic corrosion reduction in the laser-modified zone. Results of direct cell culturing suggested that the laser-modified surface exhibited good cell adhesion property, spreading performance and proliferation capacity. Special attention was focused on the influence of laser-induced patterns on cell adhesion and growth process.