Preparation And Properties Of Polydopamine-like Organic Functional Coatings

Cardiovascular disease is the leading cause of death worldwide,posing a great threat to human health and life,and coronary heart disease is a highly vascular-derived disease.At present,percutaneous coronary intervention for coronary heart disease is the main way to treat atherosclerosis clinically.Vascular stents have been widely used as clinical implant instruments commonly used in percutaneous coronary intervention.However,it is often accompanied by a series of complications such as thrombosis,inflammatory response,and late stent restenosis.Thrombosis and restenosis have become major factors limiting cardiovascular clinical applications.The problem of blood clotting caused by the surface of the material is the primary problem that cardiovascular implants need to solve.Therefore,improving the biocompatibility of cardiovascular implant materials is of great significance for the wide application of implanted devices in clinical practice.In this paper,N-3,4-dihydroxyphenethyl acrylamide(DAA)with catechol structure was synthesized for improving the biocompatibility of cardiovascular implant materials.DATA organic functional coating of polydopamine-like dopamine was prepared on the surface of the implant material by reaction of DAA with tris(2-aminoethyl)amine(TAEA).The coating was characterized and analyzed by scanning electron microscopy,in vitro immersion,water contact angle and electrochemistry.The results show that the organic functional coating has uniform surface,corrosion resistance and stability.Quantitative analysis of XPS,FTIR and amino groups indicated that the surface of the DATA organic coating contained different amino groups.The coating has much functional groups suchas amino groups,so biological multi-functionalization of the material surface can be achieved by introducing biomolecules on the surface of the DATA organic coating by chemical grafting.In addition,platelet adhesion and activation,fibrinogen denaturation experiments showed that DATA organic coating can certain anti-platelet adhesion and activation.Culture of endothelial cells and smooth muscle cells showed that the DATA organic coating can inhibitie the growth and adhesion of endothelial cells,but had no significant effect on smooth muscle cells.In order to improve the surface cytocompatibility of the DATA organic functional coating,heparin(Hep)and specific polypeptide(TK-14)were immobilized on the SS-DATA4 surface by EDC/NHS to achieve surface biochemical modification.The surface of the modified coating was characterized and analyzed by SEM,UV absorption,etc.The results show that the coating after biochemical modification has certain stability.The grafting amount of heparin and peptide was quantitatively analyzed by XPS and QCM-D.Platelet adhesion and activation as well as fibrinogen denaturation evaluation showed that the DATA biomimetic coating has good blood compatibility.The results of in vitro cell culture showed that SS-DATA4-TK-14,SS-DATA4-Hep and SS-DATA4-Hep/TK-14 could promote the proliferation and adhesion of endothelial cells and inhibit the proliferation and adhesion of smooth muscle cells.In summary,DAA and TAEA undergo Michael addition reaction and Schiff base reaction under alkaline conditions to construct an amino-rich functional coating.The coating can stably adhere to the substrate material and can be used as a secondary reaction platform to introduce other molecules to achieve material functionalization.DATA organic coatings exhibit good stability,cytocompatibility,corrosion resistance,anti-platelet adhesion and activation.The active group on the surface of the coating can be introduced into the peptide(TK-14),heparin,etc.and can maintain the original activity.The DATA organic coating can be used as a secondary reaction platform to achieve secondary functionalization.This study provides a method for preparing an amino-rich coating by using dopamine derivatives and primary amino-containing molecules.The coating can introduce multiple biomolecules to achieve secondary multi-functionalization,provides a reference for multi-functional surface of implantable instruments.