Preparation And Biocompatibility Of 4D Printed Shape Memory Drug-loaded Vascular Stent

For symptomatic vascular disease,such as vascular stenosis caused by atherosclerosis,stent implantation can expand the stenotic lesions and fix the atherosclerotic plaques and tissues that affect hemodynamics.treatment strategy.Established bioscaffolds include bare metal stents(BMS),drug-eluting stents(DES),and bioabsorbable vascular stents(BVS).DES used an antiproliferative drug in a polymer coating that inhibits intimal hyperplasia more successfully than BMS.However,drug-coated stents may lead to an initial release of the drug,leading to an increased chance of late stent thrombosis,leading to myocardial infarction or cardiac death.Four-dimensional(4D)printing is an emerging technology with a powerful capability to fabricate complex,stimulus-responsive 3D structures,offering great potential for tissue and organ engineering applications.Compared with static objects created by 3D printing,with 4D printing,we can realize that 3D printed structures can change their form or function over time under external stimuli such as temperature,light,and water,so that 3D printing has vitality.Due to the adaptability and minimally invasive nature of fabrication devices,4D printing has shown great potential in various biomedical applications.In this study,a cyclodextrin-caprolactone shape memory everolimus drug-loaded scaffold based on a thiol/acrylate fast photocuring system was designed using 4D printing technology,the bioactivity of the thiol group and the thiol-acrylate click The fast and controllable step-size polymerization mechanism of chemical reaction significantly inhibits the accumulation of reactive oxygen species,which can generate low shrinkage stress and uniform network,which greatly improves the photocuring rate,reduces the exposure to radiation,and improves the biological activity of the material.The hollow hydrophobic inner cavity of cyclodextrin and the star-like longchain structure of caprolactone can realize long-term drug loading.The composite scaffold has good mechanical properties,shape fixation,shape recovery rate,and rapid temperature responsiveness.It is worth noting that this scaffold system exhibits excellent human umbilical vein endothelial cell(HUVEC)cell adhesion,proliferation,and differentiation.The ability of in vitro hemolysis test and platelet adhesion test all meet relevant standards and can be used for human implantation.And it shows good biocompatibility during subcutaneous implantation in mice.Therefore,4D printingbased thiol-acrylate shape memory everolimus drug-loaded stents may be a promising candidate for solving restenosis after stent implantation.