Comparison study of different coatings on degradation performance and cell response of Mg-Sr alloy

• The MAO, PED and Sr-P coating were fabricated on Mg-Sr alloy to evaluate the degradation.
• The MAO coating showed the greatest degradation performance among these three coatings.
• The PED coating exhibited worse corrosion resistance even than Mg-Sr substrate.
• The value of cell proliferation and ALP activity were ranked in the following order: MAO > Sr-P > PED.

To solve the problem of rapid degradation for magnesium-based implants, surface modification especially coating method is widely studied and showed the great potential for clinical application. However, as concerned to the further application and medical translation for biodegradable magnesium alloys, there are still lack of data and comparisons among different coatings on their degradation and biological properties. This work studied three commonly used coatings on Mg-Sr alloy, including micro-arc oxidation coating, electrodeposition coating and chemical conversion coating, and compared these coatings for requirements of favorable degradation and biological performances, how each of these coating systems has performed. Finally the mechanism for the discrepancy between these coatings is proposed. The results indicate that the micro-arc oxidation coating on Mg-Sr alloy exhibited the best corrosion resistance and cell response among these coatings, and is proved to be more suitable for the orthopedic application.