Bioactive and anti-corrosive bio-MOF-1 coating on magnesium alloy for bone repair application

A novel bio-metal-organic framework (bio-MOF-1) coating was explored on the surface of AZ31B Mg alloy following silane treatment to improve the bioactivity and corrosion resistance. The surface topography of this coating is compact and homogeneous. The bioactivity of bio-MOF-1 coating was investigated through immersion test in simulated body fluid (SBF) at 37 degrees C. The results show that the bio-MOF-1 coating surface is covered fast by carbonated hydroxyapatite mineralization layer, demonstrating bio-MOF-1 coating has excellent bioactivity. We propose that the bioactivity of the bio-MOF-1 coating is mainly owing to its anionic framework, high specific surface area and the rough surface produced by bio-MOF-1 particles. In addition, the bio-MOF-1 coating can enhance effectively the corrosion resistance of Mg alloy. And the conclusion was proved by electrochemical measurement and the changes in morphology, weight and PH value. On the other hand, the mineralization layer as a new physical barrier also has great advantage to enhance the corrosion resistance of Mg alloy, compensating the degradation of bio-MOF-1 coating and offering a long term protection on Mg alloy implant. Moreover, in vitro cytotoxicity test indicates that bio-MOF-1 coating has a good biocompatibility. This work will offer a new thought for the surface modification of Mg alloys planned as bone repair implants. (C) 2019 Elsevier B.V. All rights reserved.