| Cardiovascular stent is considered one of the most effective means for treatment of coronary artery disease.However,thrombosis and in-stent restenosis（ISR）are the main obstacles during interventional therapy.With the development of coronary stent and antiplatelet therapy,ISR has been reduced in a certain extent,but the prevention of ISR remains a difficult problem in the cardiovascular stent.Surface modification of the cardiovascular stent can improve the performance of stent in the clinical treatment.The healthy and intact vascular endothelium can maintain the homeostasis of the vascular microenvironment,prevent thrombosis by regulating the behavior of platelet,and prevent ISR by regulating vascular smooth muscle cells（VSMCs）growth by releasing growth factors.It is advantageous to realize rapid reendothelialization on the implanted stent surface by introducing bioactive molecules and providing a microscopic environment favored by vascular endothelial cells（VECs）.The self-assembling peptide（RADA）4 can spontaneously self-assemble to form orderly and stableβ-sheet nanofiber structures in aqueous solution,which can further form 3-D network hydrogels by bundling and entanglement under physiological conditions.The self-assembling peptide nanofiber scaffold hydrogel is biodegradable,non-immunogenic and non-toxic,which can be applied to provide a microenvironment for cells growth as the biomimetic extracellular matrix（ECM）.The functional motif can be introduced into the peptide to form nanofibers with active motif because of its programmability.In this study,the functionalized peptide（RADA）4-GGGG-REDV with the functional motif REDV,which has been reported to selectively promote endothelial cell adhesion and spreading,was designed to form functionalized self-assembling peptide nanofiber scaffold hydrogel by self-assembling with the motif（RADA）4.The hydrogel,called REDV&RADA hydrogel,was then directly constructed on the surface of the 316L stainless steel（316L SS）substrate pretreated with polydopamine to prepare the hydrogel coating.The self-assembly behavior of the peptides was demonstrated by Congo red staining,circular dichroism（CD）,transmission electron microscopy（TEM）and zeta potential.The physicochemical properties of the hydrogel coating were characterized by Fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,water contact angle analysis,scanning electron microscopy（SEM）,detection of surface carboxyl content,thickness and stability.The results of evaluation of cytocompatibility demonstrated that the REDV&RADA hydrogel coating could selectively promote the adhesion,proliferation and migration of VECs.Besides,the results of evaluation of hemocompatibility showed that the REDV&RADA hydrogel coating could reduce the activation of prothrombin and complement system in blood,but the coating was ordinary in inhibiting platelet adhesion,fibrinogen adhesion and activation.The results of stent implantation indicated that the REDV&RADA hydrogel coated stent had the ability to promote rapid reendothelialization and inhibit intimal hyperplasia.In summary,the functionalized self-assembling peptide hydrogel,as a surface modification coating,is promising to be used to prevent the ISR and its clinical complications in clinical.In addition,this study can provide a new idea for the surface modification of vascular stent with hydrogel coatings,and provide a reference for the application of self-assembling peptide hydrogel in the surface modification of implanted devices. |
