Hollow Mesoporous Silica Nanoparticles Decorated with Cyclodextrin for Inhibiting the Corrosion of Mg Alloys

Silica-based controlled-release materials show great potential for medical-therapy applications but have also been introduced into the area of metal anticorrosion. However, few silica-based controlled-release materials are multiresponsive based on their pseudorotaxane structure and are especially responsive to metal ions. In this work, we modified hollow mesoporous silica (HMS) with cysteine (Cys) and cyclodextrin (CD) to construct a pH/glutathione (GSH)/Mg(II)-responsive nanocontainer. The pH/GSH responsiveness takes advantage of the typical charged functional group of amino acids and the unique thiol group of Cys. Mg(II) can form complexes with CD ("cap" in pseudorotaxane), which has been proven to be correlated with the pH. Further studies have revealed that the release curve can be affected by the size of a drug or macrocycle molecule and the HMS thickness. In the end, we loaded an anticorrosion inhibitor into the carrier. The results and conclusion described in this paper can be used for the rational design of a pseudorotaxane-based delivery system and to alleviate the corrosion of Mg alloys (AZ31) in a neutral 3.5% NaCl solution.