Application Of Nitric Oxide Catalytic Release Coating In Cardiovascular Medical Materials

In the medical process,the continuous development and progress of cardiovascular medical materials has brought more diversified treatment methods,which have saved more lives and created a huge market.However,there are still many problems in the clinical application of biological materials.For example,to solve the problems of blood coagulation and infection in the application of blood catheters,systemic anticoagulation and antibiotic therapy are commonly used methods,but they can cause the heparin-induced platelets and bleeding,and bacterial resistance caused by antibiotics.After the intervention of the cardiovascular stent,although the inflammatory process and intimal hyperplasia were significantly reduced in the process of drug elution,since the process of endothelialization was also inhibited by the drug,the incidence of restenosis and advanced thrombosis still existed.These diseases have a significant impact on the medical effect of cardiovascular biomaterials and the lives of patients.Surface modification of cardiovascular medical materials is an effective means to solve these problems.By improving the antibacterial properties of the materials,the possibility of iatrogenic infections can be greatly reduced,thereby reducing the use of antibiotics.By improving anti-clotting materials,dirt capacity,can reduce the material after the intervention as a foreign body caused by blood clots,to avoid the risks of systemic anticoagulation means.The increased selectivity of endothelial cells on the surface of the material avoids the indiscriminate cell inhibition of drug-eluting stents,accelerates the surface endothelialization of cardiovascular stents,and reduces the probability of restenosis and late thrombosis.Nitric oxide is an important signal molecule released by vascular endothelial,which can inhibit blood coagulation by regulating platelet cyclic guanosine monophosphate(c GMP)level,regulate the phenotype of smooth muscle,and promote the self-healing of endothelial cells.Nitric oxide(NO)while also demonstrated the ability of antibacterial and antiviral.Therefore,in this paper,the innovative construction of surface modified coating is combined with the catalytic release ability of NO,by regulating the catalytic release rate of NO and combining with other functional biomolecules,the coating is endowed with the abilities of anticoagulant,antibacterial,antifouling,inhibiting proliferation and promoting endothelialization.In this chapter,lactalbumin is oxidized by sodium persulfate(APS),which triggers changes in the secondary structure of proteins,resulting in mutual aggregation and selfassembly.This article constructs a protein cross-linked coating(α-La)with broad spectrum and versatility.Experiments have proved that there are functional groups that can be used twice on the surface of the coating,and it has a better performance than 316 L SS in terms of inflammatory factor expression and cell compatibility.In an application case,DOTA-Cu is grafted onto the surface of the coating to give it the ability to catalytically release NO and apply it to the surface modification of cardiovascular stents.The final stent implantation experiment results showed that the DOTA-Cu @α-La stent also showed a faster endothelialization process and lower intimal hyperplasia.In order to further apply the modified coating technology on the surface of various materials and adapt to various and complex working environments.Based on phenol-amine surface chemistry,ε-polylysine,hydrocaffeic acid and sodium periodate were mixed in one step to construct an ε-PL/HCA coating with a mussel bionic structure.The experimental results show that the ε-PL/HCA coating has good stability and tolerance,and huger amount of carboxyl groups and amino groups on Surface,and the ratio of amino groups to carboxyl groups can be controlled by the feed ratio,which can adapt to the needs of diversified biological materials.On this basis,the fourth chapter of this article is based on the endothelial bionic strategy,which covalently fixes DOTA-Cu,polyallylamine and hyaluronic acid(HA).Finally,a modified coating for cardiovascular stents with both the glycocalyx component on the surface of the vascular endothelium and the biomimetic NO in situ catalytic ability was constructed.And the functions of the two biomolecules are controllable and not affected by each other.Facing the two core requirements of cardiovascular stents: in terms of anticoagulation,the synergistic effect of the hydration layer formed by hyaluronic acid and the catalytic release of NO on platelet activation inhibition,the coating exhibits excellent anticoagulation ability.In terms of anti-proliferation,NO selectively inhibits smooth muscle,and accelerates the endothelialization process after stent implantation.The final stent implantation experiment results show that compared to the 316 L SS stent,the HA@DOTA-Cu stent exhibits faster endothelialization process and lower intimal hyperplasia.