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Gupta K, Meena K. A novel double arrowhead auxetic coronary stent. Comput Biol Med 2023; 166:107525. [PMID: 37778216 DOI: 10.1016/j.compbiomed.2023.107525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/17/2023] [Accepted: 09/19/2023] [Indexed: 10/03/2023]
Abstract
A stent implantation is a standard medical procedure for treating coronary artery diseases. Over the years, various different designs have been explored for the stents which come with a range of limitations, including late in-stent restenosis (due to low radial strength), foreshortening, radial recoil, etc. Contrary, stents with auxetic design, characterized by a negative Poisson's ratio, display unique deformation characteristics that result in enhanced mechanical properties in terms of its radial strength, radial recoil, foreshortening, and more. In this study, we have analysed a novel double arrowhead (DA) auxetic stent that aims to overcome the limitations associated with traditional stents, specifically in terms of radial strength, foreshortening, and radial recoil. The parametric analysis was done initially on the DA's unit ring structure to optimize the design by evaluating the effect of three design parameters (angle, amplitude, and width) on the mechanical characteristics (radial strength and radial recoil) using finite element analysis. The width of the strut was found to be the primary determinant of the stent structure's properties. Consequently, the angle and width were found to have the least effect on altering the stent's mechanical properties. After performing the parametric analysis, optimal design factors were selected to design the full-length DA auxetic stent. The mechanical characteristics of the DA auxetic stent were assessed and compared in a case study with the Cypher™ commercial stent. The radial strength of DA auxetic stent was found to be 7.26 N/mm, which is more than double the Cypher™ commercial stent's radial strength. Additionally, the proposed stent possesses reduced radial recoil property and completely eliminates the stent foreshortening issue, which shows the superior mechanical properties of the proposed auxetic stent and its potential as a promising candidate for future stent designs.
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Affiliation(s)
- Khanish Gupta
- Department of Mechanical Engineering, Indian Institute of Technology, Delhi, India.
| | - Kusum Meena
- Department of Mechanical Engineering, Indian Institute of Technology, Delhi, India.
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2
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McQueen A, Escuer J, Schmidt AF, Aggarwal A, Kennedy S, McCormick C, Oldroyd K, McGinty S. An intricate interplay between stent drug dose and release rate dictates arterial restenosis. J Control Release 2022; 349:992-1008. [PMID: 35921913 DOI: 10.1016/j.jconrel.2022.07.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/14/2022] [Accepted: 07/26/2022] [Indexed: 10/15/2022]
Abstract
Since the introduction of percutaneous coronary intervention (PCI) for the treatment of obstructive coronary artery disease (CAD), patient outcomes have progressively improved. Drug eluting stents (DES) that employ anti-proliferative drugs to limit excess tissue growth following stent deployment have proved revolutionary. However, restenosis and a need for repeat revascularisation still occurs after DES use. Over the last few years, computational models have emerged that detail restenosis following the deployment of a bare metal stent (BMS), focusing primarily on contributions from mechanics and fluid dynamics. However, none of the existing models adequately account for spatiotemporal delivery of drug and the influence of this on the cellular processes that drive restenosis. In an attempt to fill this void, a novel continuum restenosis model coupled with spatiotemporal drug delivery is presented. Our results indicate that the severity and time-course of restenosis is critically dependent on the drug delivery strategy. Specifically, we uncover an intricate interplay between initial drug loading, drug release rate and restenosis, indicating that it is not sufficient to simply ramp-up the drug dose or prolong the time course of drug release to improve stent efficacy. Our model also shows that the level of stent over-expansion and stent design features, such as inter-strut spacing and strut thickness, influence restenosis development, in agreement with trends observed in experimental and clinical studies. Moreover, other critical aspects of the model which dictate restenosis, including the drug binding site density are investigated, where comparisons are made between approaches which assume this to be either constant or proportional to the number of smooth muscle cells (SMCs). Taken together, our results highlight the necessity of incorporating these aspects of drug delivery in the pursuit of optimal DES design.
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Affiliation(s)
- Alistair McQueen
- Division of Biomedical Engineering, University of Glasgow, Glasgow, UK
| | - Javier Escuer
- Aragón Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | | | - Ankush Aggarwal
- Glasgow Computational Engineering Centre, Division of Infrastructure and Environment, University of Glasgow, Glasgow, UK
| | - Simon Kennedy
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | | | - Keith Oldroyd
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Sean McGinty
- Division of Biomedical Engineering, University of Glasgow, Glasgow, UK; Glasgow Computational Engineering Centre, Division of Infrastructure and Environment, University of Glasgow, Glasgow, UK.
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Bioresponsive starPEG-heparin hydrogel coatings on vascular stents for enhanced hemocompatibility. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 128:112268. [PMID: 34474827 DOI: 10.1016/j.msec.2021.112268] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/02/2021] [Accepted: 06/13/2021] [Indexed: 11/20/2022]
Abstract
Hydrogel coatings can improve the biocompatibility of medical devices. However, stable surface bonding and homogeneity of hydrogel coatings are often challenging. This study exploits the benefits of biohybrid hydrogels of crosslinked four-armed poly(ethylene glycol) and heparin to enhance the hemocompatibility of cobalt‑chromium (CoCr) vascular stents. A bonding layer of dual silane and poly(ethylene-alt-maleic anhydride) (PEMA) treatment was applied to the stent to provide covalent immobilization and hydrophilicity for the homogeneous spreading of the hydrogel. A spray coating technology was used to distribute the aqueous solution of the reactive hydrogel precursors onto the sub-millimeter struts of the stents, where the solution polymerized to a homogeneous hydrogel film. The coating was mechanically stable on the stent after ethanol dehydration, and the stents could be stored in a dry state. The homogeneity and stability of the coating during stent expansion were verified. Quasistatic and dynamic whole blood incubation experiments showed substantial suppression of the pro-coagulant and inflammatory activity of the bare metal by the coating. Translation of the technology to industrial coating devices and future surface modification of stents with anti-inflammatory hydrogels are discussed.
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Gagliardi M. Numerical analysis of paclitaxel-eluting coronary stents: Mechanics and drug release properties. Med Eng Phys 2020; 82:78-85. [PMID: 32709268 DOI: 10.1016/j.medengphy.2020.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 04/14/2020] [Accepted: 06/15/2020] [Indexed: 10/23/2022]
Abstract
Since theoretical models provide data that cannot be otherwise gathered, numerical methods applied to medical devices analysis have emerged as fundamental tool in preclinical development. Large efforts were done to study mechanical and drug-eluting properties in stents but often the coating modelling is neglected. This work presents a finite element framework to calculate mechanical loads and drug distribution in three commercial drug-eluting stents (Palmaz-Schatz, Palmaz Genesis and Multi Link Vision), to check coatings strength and drug distribution maps in biological tissues. The promising copolymer poly(methylmethacrylate-co-n-butylmethacrylate), loaded with paclitaxel, is analyzed. Results demonstrated that the coating undergoes localized plastic phenomena, and calculated stresses are lower than the ultimate stress, ensuring coating integrity. Computed drug concentration depends on stent geometry and its values are in all cases lower than the toxicity level for this drug.
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Escuer J, Cebollero M, Peña E, McGinty S, Martínez MA. How does stent expansion alter drug transport properties of the arterial wall? J Mech Behav Biomed Mater 2020; 104:103610. [DOI: 10.1016/j.jmbbm.2019.103610] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/23/2019] [Accepted: 12/29/2019] [Indexed: 11/28/2022]
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6
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Gagliardi M. Adhesion properties of poly(methylmethacrylate‐
co
‐
n
‐butylmethacrylate) copolymers in stent coatings. J Appl Polym Sci 2019. [DOI: 10.1002/app.47814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Chen C, Tan J, Wu W, Petrini L, Zhang L, Shi Y, Cattarinuzzi E, Pei J, Huang H, Ding W, Yuan G, Migliavacca F. Modeling and Experimental Studies of Coating Delamination of Biodegradable Magnesium Alloy Cardiovascular Stents. ACS Biomater Sci Eng 2018; 4:3864-3873. [DOI: 10.1021/acsbiomaterials.8b00700] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Chenxin Chen
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | - Jinyun Tan
- Department of Vascular Surgery, Huashan Hospital of Fudan University, No. 12 Mid-Wulumuqi Road, Shanghai 200040, China
| | - Wei Wu
- Department of Mechanical Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249-0669, United States
| | | | - Lei Zhang
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | - Yongjuan Shi
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | | | - Jia Pei
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | - Hua Huang
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | - Wenjiang Ding
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
| | - Guangyin Yuan
- National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China, 200240
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Stents: Biomechanics, Biomaterials, and Insights from Computational Modeling. Ann Biomed Eng 2017; 45:853-872. [PMID: 28160103 DOI: 10.1007/s10439-017-1806-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/28/2017] [Indexed: 01/02/2023]
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Saito N, Mori Y, Uchiyama S. Drug diffusion and biological responses of arteries using a drug-eluting stent with nonuniform coating. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2016; 9:33-43. [PMID: 27051322 PMCID: PMC4803265 DOI: 10.2147/mder.s102094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to determine the effect of a nonuniform coating, abluminal-gradient coating (AGC), which leaves the abluminal surface of the curves and links parts of the stent free from the drug coating, on the diffusion direction of the drug and the biological responses of the artery to drug-eluting stent (DES) by comparing the AGC-sirolimus stent and the conventional full-surface coating (CFC) sirolimus stent. The study aimed to verify whether the AGC approach was appropriate for the development of a safer DES, minimizing the risks of stent thrombosis due to delayed endothelialization by the drug and distal embolization due to cracking of the coating layer on the hinge parts of the DES on stent expansion. In the in vitro local drug diffusion study, we used rhodamine B as a model drug, and rhodamine B released from the AGC stent diffused predominantly into the abluminal side of the alginate artery model. Conversely, rhodamine B released from the CFC stent quickly spread to the luminal side of the artery model, where endothelial cell regeneration is required. In the biological responses study, the luminal surface of the iliac artery implanted with the AGC-sirolimus stent in a rabbit iliac artery for 2 weeks was completely covered with endothelial-like cells. On the other hand, the luminal surface of the iliac artery implanted with the CFC-sirolimus stent for 2 weeks only showed partial coverage with endothelial-like cells. While thrombosis was observed in two of the three CFC-sirolimus stents, it was observed in only one of the three AGC-sirolimus stents. Taken together, these findings indicate that the designed nonuniform coating (AGC) is an appropriate approach to ensure a safer DES. However, the number of studies is limited and a larger study should be conducted to reach a statistically significant conclusion.
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Affiliation(s)
- Noboru Saito
- Terumo Corporation R&D Center, Inokuchi, Nakai-machi, Ashigarakami-gun, Kanagawa, Japan
| | - Yuhei Mori
- Terumo Corporation R&D Center, Inokuchi, Nakai-machi, Ashigarakami-gun, Kanagawa, Japan
| | - Sayaka Uchiyama
- Terumo Corporation R&D Center, Inokuchi, Nakai-machi, Ashigarakami-gun, Kanagawa, Japan
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Hopkins C, Sweeney CA, O’Connor C, McHugh PE, McGarry JP. Webbing and Delamination of Drug Eluting Stent Coatings. Ann Biomed Eng 2015; 44:419-31. [DOI: 10.1007/s10439-015-1490-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
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WU WEI, MERCURI MASSIMILIANO, PEDRONI CHIARA, MIGLIAVACCA FRANCESCO, PETRINI LORENZA. A COMPUTATIONAL STUDY TO INVESTIGATE DEBONDING IN COATED BIORESORBABLE STENTS. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415400151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A new trend in the treatment of atherosclerosis foresees the exploitation of bioresorbable materials for stents. Magnesium alloys are good candidates since they are completely biocorrodible in human body. To overcome the limitation of very fast degradation, the bioresorbable scaffold can be coated with a polymer having lower degradation rate and taking advantages by coupling metal and polymer properties. However, the coating has a risk of debonding due to the high strain the stent undergoes during the expansion. In this paper two-dimensional (2D) finite element analyses are performed to provide a greater understanding of coating delamination and to show how computational analyses can be usefully employed in the design of coated bioresorbable stents.
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Affiliation(s)
- WEI WU
- Chemistry, Materials and Chemical Engineering 'Giulio Natta' Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan, 20131, Italy
| | - MASSIMILIANO MERCURI
- Chemistry, Materials and Chemical Engineering 'Giulio Natta' Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan, 20131, Italy
| | - CHIARA PEDRONI
- Chemistry, Materials and Chemical Engineering 'Giulio Natta' Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan, 20131, Italy
| | - FRANCESCO MIGLIAVACCA
- Chemistry, Materials and Chemical Engineering 'Giulio Natta' Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan, 20131, Italy
| | - LORENZA PETRINI
- Civil and Environmental Engineering Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan, 20131, Italy
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Schiavone A, Zhao L, Abdel-Wahab A. Effects of material, coating, design and plaque composition on stent deployment inside a stenotic artery—Finite element simulation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 42:479-88. [DOI: 10.1016/j.msec.2014.05.057] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 04/18/2014] [Accepted: 05/29/2014] [Indexed: 01/19/2023]
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13
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FEA Study on the Stress Distributions in the Polymer Coatings of Cardiovascular Drug-Eluting Stent Medical Devices. Ann Biomed Eng 2014; 42:1952-65. [DOI: 10.1007/s10439-014-1047-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 05/28/2014] [Indexed: 10/25/2022]
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14
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On the effect of macromolecular composition and drug loading on thermal and tensile mechanical properties of methyl methacrylate and butyl methacrylate copolymers. Polym Bull (Berl) 2013. [DOI: 10.1007/s00289-013-1075-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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15
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Denardo SJ, Carpinone PL, Vock DM, Tcheng JE, Phillips HR, Willenberg BJ, Batich CD, Pepine CJ. Detailed analysis of polymer response to delivery balloon expansion of drug-eluting stents versus bare metal stents. EUROINTERVENTION 2013; 9:389-97. [DOI: 10.4244/eijv9i3a62] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Taylor EN, Kummer KM, Durmus NG, Leuba K, Tarquinio KM, Webster TJ. Superparamagnetic iron oxide nanoparticles (SPION) for the treatment of antibiotic-resistant biofilms. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:3016-27. [PMID: 22777831 DOI: 10.1002/smll.201200575] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 04/24/2012] [Indexed: 05/14/2023]
Abstract
Bacterial infections caused by antibiotic-resistant strains are of deep concern due to an increasing prevalence, and are a major cause of morbidity in the United States of America. In particular, medical device failures, and thus human lives, are greatly impacted by infections, where the treatments required are further complicated by the tendency of pathogenic bacteria, such as Staphylococcus aureus, to produce antibiotic resistant biofilms. In this study, a panel of relevant antibiotics used clinically including penicillin, oxacillin, gentamicin, streptomycin, and vancomycin are tested, and although antibiotics are effective against free-floating planktonic S. aureus, either no change in biofilm function is observed, or, more frequently, biofilm function is enhanced. As an alternative, superparamagnetic iron oxide nanoparticles (SPION) are synthesized through a two-step process with dimercaptosuccinic acid as a chelator, followed by the conjugation of metals including iron, zinc, and silver; thus, the antibacterial properties of the metals are coupled to the superparamagnetic properties of SPION. SPION might be the ideal antibacterial treatment, with a superior ability to decrease multiple bacterial functions, target infections in a magnetic field, and had activity better than antibiotics or metal salts alone, as is required for the treatment of medical device infections for which no treatment exists today.
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Affiliation(s)
- Erik N Taylor
- Center for Biomedical Engineering and School of Engineering, Brown University, Providence, Rhode Island, USA
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Parry G, McGarry P. An analytical solution for the stress state at stent–coating interfaces. J Mech Behav Biomed Mater 2012; 10:183-96. [DOI: 10.1016/j.jmbbm.2012.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 02/08/2012] [Accepted: 02/13/2012] [Indexed: 10/28/2022]
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Bakhshi R, Darbyshire A, Evans JE, You Z, Lu J, Seifalian AM. Polymeric coating of surface modified nitinol stent with POSS-nanocomposite polymer. Colloids Surf B Biointerfaces 2011; 86:93-105. [PMID: 21515031 DOI: 10.1016/j.colsurfb.2011.03.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/14/2011] [Accepted: 03/18/2011] [Indexed: 11/19/2022]
Abstract
Stent angioplasty is a successful treatment for arterial occlusion, particularly in coronary artery disease. The clinical communities were enthusiastic about the use of drug-eluting stents; however, these stents have a tendency to be a contributory factor towards late stage thrombosis, leading to mortality in a significant number of patients per year. This work presents an innovative approach in self-expanding coronary stents preparation. We developed a new nanocomposite polymer based on polyhedral oligomeric silsesquioxanes (POSS) and poly(carbonate-urea)urethane (PCU), which is an antithrombogenic and a non-biodegradable polymer with in situ endothelialization properties. The aim of this work is to coat a NiTi stent alloy with POSS-PCU. In prolonged applications in the human body, the corrosion of the NiTi alloy can result in the release of deleterious ions which leads to unwanted biological reactions. Coating the nitinol (NiTi) surface with POSS-PCU can enhance surface resistance and improve biocompatibility. Electrohydrodynamic spraying was used as the polymer deposition process and thus a few experiments were carried out to compare this process with casting. Prior to deposition the NiTi has been surface modified. The peel strength of the deposit was studied before and after degradation of the coating. It is shown that the surface modification enhances the peel strength by 300%. It is also indicated how the adhesion strength of the POSS-PCU coating changes post-exposure to physiological solutions comprised of hydrolytic, oxidative, peroxidative and biological media. This part of the study shows that the modified NiTi presents far greater resistance to decay in peel strength compared to the non-modified NiTi.
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Affiliation(s)
- Raheleh Bakhshi
- University College London, Centre for Nanotechnology and Regenerative Medicine, London, UK
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Seidlitz A, Nagel S, Semmling B, Grabow N, Martin H, Senz V, Harder C, Sternberg K, Schmitz KP, Kroemer HK, Weitschies W. Examination of drug release and distribution from drug-eluting stents with a vessel-simulating flow-through cell. Eur J Pharm Biopharm 2010; 78:36-48. [PMID: 21182943 DOI: 10.1016/j.ejpb.2010.12.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/08/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
Abstract
The recently introduced vessel-simulating flow-through cell offers new possibilities to examine the release from drug-eluting stents in vitro. In comparison with standard dissolution methods, the additional compartment allows for the examination of distribution processes and creates dissolution conditions which simulate the physiological situation at the site of implantation. It was shown previously that these conditions have a distinct influence on the release rate from the stent coating. In this work, different preparation techniques were developed to examine the spatial distribution within the compartment simulating the vessel wall. These methods allowed for the examination of diffusion depth and the distribution resulting in the innermost layer of the compartment simulating the vessel wall. Furthermore, the in vitro release and distribution examined experimentally were modelled mathematically using finite element (FE) methods to gain further insight into the release and distribution behaviour. The FE modelling employing the experimentally determined diffusion coefficients yielded a good general description of the experimental data. The results of the modelling also provided important indications that inhomogeneous coating layer thicknesses around the strut may result from the coating process which influence release and distribution behaviour. Taken together, the vessel-simulating flow-through cell in combination with FE modelling represents a unique method to analyse drug release and distribution from drug-eluting stents in vitro with particular opportunities regarding the examination of spatial distributions within the vessel-simulating compartment.
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Affiliation(s)
- Anne Seidlitz
- Institute of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, EMA University of Greifswald, Greifswald, Germany.
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