Development of functional coatings for the controlled degradation and corrosion protection of biocompatible Mg alloys

摘要

The advantage of using magnesium alloys over traditional metals, biodegradable polymer andceramics lies on their superior mechanical properties and their biocompatibility and biodegradability[1]. This advantage makes them suitable for biomedical applications [2] but prone to corrosion,therefore their biggest advantage is simultaneously a challenge [1]. Magnesium alloys degradation,by corrosion, is fast, localized, inhomogeneous and uncontrolled [2, 3]. In addition, it is usuallyaccompanied by hydrogen formation which lead to complications when used in biomedicalapplications [4].In this work we propose the development of a functional coating where gelatin-based capsules areincorporated for the controlled release of relevant active species. It aims at controlling and delayingMg alloy degradation. To achieve this a multistep approach is tackled: (1) Application ofappropriate surface treatments, (2) synthesis of gelatin-based capsules with biocompatiblecorrosion inhibitors, (3) selection of a coating or combination of coating formulations that will delayMg degradation, (4) Biocompatibility of all the materials in a biological environment (4) corrosiondegradation studies of selected coatings containing capsules.Gelatin capsules containing Ca2+were incorporated in different coating formulations and applied ondifferent Mg Alloys (Mg1Ca, Mg10Gd). Their behavior in corrosion prone environment was testedby different electrochemical techniques (DC polarization, electrochemical impedancespectroscopy). In addition, the different coating formulations were tested in relevant biologicalenvironments to access their biocompatibility and toxicity.