Design and evaluation of mixed self-assembled monolayers for a potential use in everolimus eluting coronary stents.

Coronary artery disease (CAD) is still the leading cause of death throughout the world. Metal stents are used to widen narrowed arteries. In addition, drug-eluting stents (DES) are widely implanted to decrease the risk of in-stent restenosis. Commercially available polymer-based DES suffer from some limitations. To avoid these drawbacks, the use of self-assembled monolayers (SAMs) in DES has recently been investigated. In this study, methyl- and carboxyl-terminated mixed SAMs on gold (Au) surfaces were successfully prepared. The samples were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and contact angle goniometry (CA). The mixed SAM-coated surfaces were evaluated for everolimus delivery. The drug release in PBS was studied using high performance liquid chromatography (HPLC) and quartz crystal nanobalance (QCN). The results were compared with those related to homogenous SAM-coated surfaces. Significant differences (p<0.05) were found in the amount of drug eluted between the mixed SAM and the homogenous one. The findings are promising for the application of mixed SAMs in DES.