Development of Blood Compatible Alpha-lipoic acid Coated Stent with a Good Adhesive by Low Temperature Plasma Polymeriza
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1132-Z08-01
Development of Blood Compatible Alpha-lipoic acid Coated Stent with a Good Adhesive by Low Temperature Plasma Polymerization Sun-Jung Song1, Kyoung Seok Kim1, Dong Lyun Cho1*, Myung Ho Jeong2 1 Center for Functional Nano Fine Chemicals, 2nd stage of Brain Korea 21, Chonnam National University, Gwangju 500-757, Korea 2
The Heart Center of Chonnam National University Hospital
ABSTRACT Neointimal hyperplasia is a main cause for in-stent restenosis after stent-implantation and is triggered by inflammatory response to foreign materials. It can be inhibited if the stent is modified to have good blood compatibility by coating drug compounds. Low temperature plasma polymerization of 1,2-diaminocyclohexane was performed to prepare more adhesive polymeric thin film onto the metallic stent. Then, the chemical grafting of α-lipoic acid (ALA) was carried out to improve blood compatibility of stent. Drugs containing carboxylic groups can be chemically grafted through the formation of amide bond in the presence of 1-ethyl-3-(3dimethylaminopropyl) carbodiimide methiodide onto the DACH deposited stent surface. ALA grafted film showed good mechanical stability and blood compatibility. INTRODUCTION The drug eluting stent reduced the rate of restenosis as compared with bare metal stent by preventing proliferation or thrombus formation [1-3]. In-stent restenosis, however, still remained even after drug eluting stent. Many efforts have been performed by coating onto the metallic stent surface with anti-proliferative and anti-inflammatory drugs to inhibit in-stent restenosis aroused by anti-proliferative and inflammatory response. Most conventional drug eluting stents were coated with polymeric matrix onto the metallic stent surface to combine drug compound. These drug containing polymeric matrices must inhibit the platelet aggregation and inflammation but these polymer thin films usually possess poor adhesion to the stent surface. So, the remaining synthetic polymer may cause inflammatory reaction or late thrombosis after drug elutes [4-5]. Therefore, it is important to improve adhesion between stent surface and drug containing polymeric matrix. In this presentation, we tried to prepare more adhesive drug containing polymeric thin film onto the metallic stent using low temperature plasma polymerization process and to improve blood compatibility by grafting α-lipoic acid (ALA). It has been reported that ALA may be used to inhibit the develop neointimal hyperplasia [6-7]. So, metal stent surface was modified with DACH (1,2-diaminocyclic hexane) to have amine functional group on the surface of metal stent by low temperature plasma polymerization process at first [8]. Then, the amine group on the surface of stents could be chemically grafted with carboxyl group in ALA to form the amide bond in the presence of carbodiimides. It was also investigated some factors influencing the amide formation in grafting reactions, such as pH, molar ratio of ALA to carbodiimieds. To identify of attachment ALA grafted polymeric thin film betwee
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