title: Effects of interfacial layer wettability and thickness on the coating morphology and sirolimus release for drug-eluting stent.
abstract: Drug-eluting stents (DESs) have been used to treat coronary artery diseases by placing in the arteries. However, current DESs still suffer from polymer coating defects such as delamination and peeling-off that follows stent deployment. Such coating defects could increase the roughness of DES and might act as a source of late or very late thrombosis and might increase the incident of restenosis. In this regard, we modified the cobalt-chromium (Co-Cr) alloy surface with hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) or hydrophobic poly(2-hydroxyethyl methacrylate)-grafted-poly(caprolactone) (PHEMA-g-PCL) brushes. The resulting surfaces were biocompatible and biodegradable, which could act as anchoring layer for the drug-in-polymer matrix coating. The two modifications were characterized by ATR-FTIR, XPS, water contact angle measurements, SEM and AFM. On the control and modified Co-Cr samples, a sirolimus (SRL)-containing poly(D,L-lactide) (PDLLA) were ultrasonically spray-coated, and the drug release was examined for 8weeks under physiological conditions. The results demonstrated that PHEMA as a primer coating improved the coating stability and degradation morphology, and drug release profile for short-term as compared to control Co-Cr, but fails after 7weeks in physiological buffer. On the other hand, the hydrophobic PHEMA-g-PCL brushes not only enhanced the stability and degradation morphology of the PDLLA coating layer, but also sustained SRL release for long-term. At 8-week of release test, the surface morphologies and release profiles of coated PDLLA layers verified the beneficial effect of hydrophobic PCL brushes as well as their thickness on coating stability. Our study concludes that 200nm thickness of PHEMA-g-PCL as interfacial layer affects the stability and degradation morphology of the biodegradable coating intensively to be applied for various biodegradable-based DESs.
authors: Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology, 113 Gwahangno, Yuseong-gu, Daejeon 305-333, Republic of Korea; Chemistry Department, Faculty of Science, Minia University, El-Minia 61519, Egypt.
authors: Tarek M
authors: TM
authors: Bedair
authors: Department of Chemical and Biomolecular Engineering, and Graphene Research Center, KI for NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors: Seung Jung
authors: SJ
authors: Yu
authors: Department of Chemical and Biomolecular Engineering, and Graphene Research Center, KI for NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors: Sung Gap
authors: SG
authors: Im
authors: Department of Electronic Engineering & Institute of Gachon Fusion Technology, Gachon University, Gyeonggi 146-701, Republic of Korea.
authors: Bang Ju
authors: BJ
authors: Park
authors: Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology, 113 Gwahangno, Yuseong-gu, Daejeon 305-333, Republic of Korea. Electronic address: ykjoung@kist.re.kr.
authors: Yoon Ki
authors: YK
authors: Joung
authors: Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea; Department of Biomedical Engineering, Korea University of Science and Technology, 113 Gwahangno, Yuseong-gu, Daejeon 305-333, Republic of Korea. Electronic address: dkh@kist.re.kr.
authors: Dong Keun
authors: DK
authors: Han
mesh_terms: D000497:Alloys; D002021:Buffers; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002858:Chromium Alloys / Q000737:chemistry; D020099:Coated Materials, Biocompatible; D016503:Drug Delivery Systems; D065546:Drug Liberation; D054855:Drug-Eluting Stents; D006801:Humans; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D010949:Plasma / Q000187:drug effects; D011091:Polyesters / Q000737:chemistry; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry; D020123:Sirolimus / Q000008:administration & dosage*; D013052:Spectrometry, X-Ray Emission; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D000497:Alloys; D002021:Buffers; D002858:Chromium Alloys; D020099:Coated Materials, Biocompatible; D011091:Polyesters; D014867:Water; C016240:polycaprolactone; D011102:Polyhydroxyethyl Methacrylate; C033616:poly(lactide); D020123:Sirolimus
keywords: Biodegradable polymer; Drug-eluting stent; Photo-initiated chemical vapor deposition; Polymer brush; Ring-opening polymerization