A bilayer coating of nHA/PLGA to progress Mg corrosion resistance and cytocompatibility for orthopedic application

Abstract

The similar mechanical properties of magnesium and its alloys to natural bone, along with their appropriate biodegradability, make them promising candidates for orthopedic implant applications. However, there are concerns regarding their poor corrosion resistance. In this study, a double-layer coating of ceramic-polymer (nHA/PLGA) was applied to Mg to address this challenge. In the first step, the hydroxyapatite coating was deposited using the electrodeposition method. The poly(lactic-co-glycolic) acid coating was then applied to the coated samples using the dip method. Scanning electron microscopy of the samples reveals a uniform double-layer coating with a thickness ranging from 20 to 30 μm. The mechanical properties of the coatings were examined through the indentation testing, which revealed a higher degree of adhesion of the double-layer coating to the substrate. Potentiodynamic polarization of the double-layer coating indicates an increase in the corrosion potential from −1.82 to −1.4 V and a decrease in the corrosion current from 2.3 to 0.37 μA/cm2. Moreover, the MTT assay of double-layer coated samples showed an increase in cell proliferation near the 48-h extract of the samples. This indicates a decrease in the release of ions from the surface of magnesium when this coating is applied.

Keywords

• Magnesium
• Hydroxyapatite
• Poly (lactic-co-glycolic) acid
• Double-layer coating
• Corrosion
• Biocompatibility