title: ALD mediated heparin grafting on nitinol for self-expanded carotid stents.
abstract: Carotid-artery atherosclerosis is a common cause of ischemic stroke. Carotid-artery stenting (CAS) is one of the most effective treatments. However, In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent which affect clinical safety and reduce effects. In this study, atomic layer deposition (ALD) technology was applied to deposit a layer (10nm) of Al2O3 on Nitinol surface as an intermediate functional layer. The alumina covered surface was then modified with a coupling agent 3-aminopropyltriethoxysilane (APS) and heparin sequentially in order to improve the hemocompatibility of Nitinol stents. The successful graft of APS and heparin onto Nitinol was proven by X-ray photoelectron spectroscopy. Furthermore, the predicted improvement in the biocompatibilities of modified Nitinol was confirmed by water contact angle measurement, protein adsorption, platelet adhesion, and plasma recalcification time determination. The results of hemolysis assay, cell proliferation and cytotoxicity tests revealed that the grafting of heparin on NiTi kept the original positive performance of nitinol material. The results indicate that ALD technology is of great potential for the manufacture of medical devices, especially for surface modifications and functionalization. ALD technology can help with modifications of inert metallic surfaces and therefore benefit implantable medical devices, especially intravascular stents.
authors.affiliation: College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; Nanjing Excellence Technology Center for Interventional Medical Devices, Nanjing 210093, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; Nanjing Excellence Technology Center for Interventional Medical Devices, Nanjing 210093, China.
authors.forename: Xiumian
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Shanghai Huashan Hospital, Shanghai 200040, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Leng
authors.affiliation: Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an 223003, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China; Nanjing Excellence Technology Center for Interventional Medical Devices, Nanjing 210093, China. Electronic address: ztnj@nju.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D000497:Alloys / Q000737:chemistry* / Q000494:pharmacology; D000537:Aluminum Oxide / Q000737:chemistry* / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006493:Heparin / Q000737:chemistry*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D056951:Photoelectron Spectroscopy; D010973:Platelet Adhesiveness / Q000187:drug effects; D061251:Primary Cell Culture; D011437:Propylamines / Q000737:chemistry; D000069322:Self Expandable Metallic Stents; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012821:Silanes / Q000737:chemistry
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D011437:Propylamines; D012821:Silanes; D012710:Serum Albumin, Bovine; C013616:nitinol; D006493:Heparin; C477625:amino-propyl-triethoxysilane; D000537:Aluminum Oxide
keywords: Atomic layer deposition; Heparin; Nitinol stents; Surface modification