Studies On From Surface To Bulk Modification:Plasma Polymerized Amine-bearing Coating By Synergic Strategy Of Biomolecule Grafting And Nitric Oxide Loading

Along with the development and application of a series of blood contact materials such as artificial blood vessels and vascular stents,the treatment and diagnosis of cardiovascular diseases have been improved.But the problems of blood compatibility on the surface of materials have become the key to its successful application in clinical practice.When vessel are damaged or the material comes into contact with blood,a series of coagulation factors,such as thrombin and platelet,are activated and involve in the blood coagulation process,and triggers the coagulation cascade,leading to thrombosis.Therefore,thrombin activation and platelet activation adhesion become the important factors in the blood coagulation process.The thrombin direct inhibitor bivalirudin(BVLD),which specifically binds to thrombin,not only inhibits free thrombin,but also inhibits thrombus-bound thrombin,and occupies fibrin by binding to thrombin,causing the inhibition of fibrin production and reducing thrombosis.Endogenous nitric oxide(NO)has the function of inhibiting platelet activation and aggregation and reduces the calcium ion concentration required for platelet activation by activating guanylate cyclase(GC)of target cell such as platelets,and finally increasing the amount of cyclic guanosine monophosphate(cGMP).Based on this,a novel surface modification coating strategy was constructed to achieve the design of a synergistic anticoagulant multi-functional surface coating that inhibits thrombin and platelet activation.In this paper,316 L stainless steel was used as the base material,and allylamine and hexafluoroethane were used as polymerizable monomers.Plasma polyallylamine(PPAm)and fluorocarbon(C-F)polymerized alternating coatings was deposited on the surface of 316 L SS by alternating stacking.Anticoagulant biomolecules-BVLD was grafted on the surface of plasma-polymerized alternating coatings by primary amines,secondary amines in the coatings were converted to azodiol enol to store NO.The synergistic anticoagulant multifunctional surface coating was constructed by the combination of BVLD and NO.The results of water contact angle detection,fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)showed that the hydrophilicity of the stainless steel surface modified by the alternating polymer coating was improved and maintained the structure of the original monomer.After the alternating coating on the surface of the material with the BVLD and NO,the hydrophilicity of surface was significantly improved.The results of FTIR and XPS and NO release confirmed that the BVLD and NO were successfully fixed in the coating.The C-F Polymerized Coating in the alternating coating can significantly prolong the release of NO in the coating,overcoming the short duration of NO release.The results of compatibility experiments showed that the blood compatibility of the coatings modified by BVLD and NO were significantly improved.While double-modified by BVLD and NO,the BVLD/NO-PPAmF surface had the excellent anticoagulant effect.This provided a new strategy and method for the development of multifunctional anticoagulant coatings in the future.