A redox-sensitive coating with disulfide bonds is a promising candidate for surface-modified interventional devices

Many diseases are accompanied by changes in the redox environment, such as the reducing environment of the tumor cytoplasmic matrix and oxidative stress and the pathological microenvironment of coronary heart disease. The surface modification of interventional devices often ignores these environmental changes. A redox-sensitive coating can better adapt to the changes of pathological environment and achieve more accurate treatment of diseases. In response to these environmental changes, we constructed a sensitive coating to modify the surface of interventional devices. Two kinds of functional molecules, epigallocatechin gallate (EGCG) and cystamine, were chosen to construct the redox-sensitive coating. The phenolic hydroxyl group of EGCG could chelate metal ions and enable it to bind to a metal substrate, while cystamine molecules containing disulfide bonds (-S-S-) can react with EGCG through Michael addition and Schiff base reactions to form EGCG-Cys crosslinked coatings. The disulfide bond in the coating could respond to the redox environment, which could be reduced to-SH by glutathione (GSH) or oxidized to-SO3H by reactive oxygen species (ROS). The sensitivity and response capability of the coating were determined via X-ray photoelectron spectroscopy (XPS) and quartz crystal microbalance (QCM-D) analysis. Furthermore, the safety and cytocompatibility of the coating were evaluated using an in vitro co-culture of vascular endothelial cells (ECs) and smooth muscle cell (SMCs). The histocompatibility of the coating in vivo was confirmed via subcutaneous implantation in rats. Overall, we found that the redox-sensitive coating has potential applications for the surface modification of interventional devices.