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stent AND Fe

Chunling Qin, Qingfeng Hu, Yongyan Li, Zhifeng Wang, Weimin Zhao, Dmitri V Louzguine-Luzgin, Akihisa Inoue
We demonstrate, for the first time, that the (Fe0.75B0.15Si0.1)100-xNbx (x=0, 1 and 3at.%) metallic glasses without toxic and allergic elements exhibit excellent apatite-forming ability in simulated body fluids (SBF), which is expected to be a new generation of biomaterials in stents and orthopedic implants. For the alloys without any surface treatment, spherical particles corresponding to octacalcium phosphate are spontaneously nucleated and precipitated throughout the alloy surface after immersion only for 1day, indicating that the present alloys possess an unusual high bioactivity...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
E Mostaed, M Sikora-Jasinska, A Mostaed, S Loffredo, A G Demir, B Previtali, D Mantovani, R Beanland, M Vedani
The search for a degradable metal simultaneously showing mechanical properties equal or higher to that of stainless steel and uniform degradation is still an open challenge. Several magnesium-based alloys have been studied, but their degradation rate has proved to be too fast and rarely homogeneous. Fe-based alloys show appropriate mechanical properties but very low degradation rate. In the present work, four novel Zn-Mg and two Zn-Al binary alloys were investigated as potential biodegradable materials for stent applications...
July 2016: Journal of the Mechanical Behavior of Biomedical Materials
Ali I Alherz, Omar Tanweer, Vittoria Flamini
Dual-layer stents and multi-layer stents represent a new paradigm in endovascular interventions. Multi-layer stents match different stent designs in order to offer auxiliary functions. For example, dual-layer stents used in the endovascular treatment of intracranial aneurysms, like the FRED(TM) (MicroVention, CA) stent, combine a densely braided inner metallic mesh with a loosely braided outer mesh. The inner layer is designed to divert blood flow, whereas the outer one ensures microvessels branching out of the main artery remain patent...
August 16, 2016: Journal of Biomechanics
Essowè Mouzou, Carlo Paternoster, Ranna Tolouei, Agung Purnama, Pascale Chevallier, Dominique Dubé, Frédéric Prima, Diego Mantovani
High manganese austenitic steels such as Fe-20Mn-1.2C alloys are among the most promising candidates for biodegradable stents applications due to their high strength, high ductility and their chemical composition. In the current work, 14 day static in-vitro tests were performed in controlled atmosphere to assess the degradation behavior in three common pseudo-physiological solutions, i.e. commercial Hanks' (CH), modified Hanks' (MH) and albumin-enriched Dulbecco's modified phosphate buffered saline (DPBS) solutions...
April 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Francesco Iannaccone, Matthieu De Beule, Sander De Bock, Imramsjah M J Van der Bom, Matthew J Gounis, Ajay K Wakhloo, Matthieu Boone, Benedict Verhegghe, Patrick Segers
Clinical studies have demonstrated the efficacy of stent supported coiling for intra-cranial aneurysm treatment. Despite encouraging outcomes, some matters are yet to be addressed. In particular closed stent designs are influenced by the delivery technique and may suffer from under-expansion, with the typical effect of "hugging" the inner curvature of the vessel which seems related to adverse events. In this study we propose a novel finite element (FE) environment to study potential failure able to reproduce the microcatheter "pull-back" delivery technique...
February 2016: Annals of Biomedical Engineering
Jennifer Frattolin, Rajib Barua, Huseyin Aydin, Sriraman Rajagopalan, Luca Gottellini, Richard Leask, Stephen Yue, David Frost, Olivier F Bertrand, Rosaire Mongrain
The implementation of biodegradable stents has the potential to revolutionize obstructive coronary artery disease treatment. Limitations still currently exist, however, that prevent biodegradable stents from replacing permanent metallic stents in the global market. The ideal combination of stent properties, including sufficient mechanical strength, controlled degradation, and biocompatibility, has yet to be realized. A novel manufacturing process is proposed that utilizes cold gas-dynamic spraying to fabricate a metal structure with significantly reduced grain size...
February 2016: Annals of Biomedical Engineering
Daria Cosentino, Claudio Capelli, Graham Derrick, Sachin Khambadkone, Vivek Muthurangu, Andrew M Taylor, Silvia Schievano
AIMS: We report the application of patient-specific computational models to plan the treatment of complex aortic re-coarctation (rCoA) with a proximal aberrant right subclavian artery in a patient who had previously undergone bare metal stenting. METHODS AND RESULTS: Clinically acquired images were used to set up patient-specific computational models for finite element (FE) and fluid dynamics (CFD) analyses. The 3D geometry was reconstructed from computed tomography and echocardiography images...
October 2015: EuroIntervention
Sufia Islam, Stefan Jarosch, Juan Zhou, Maria del Carmen Parquet, James Thomas Toguri, Patricia Colp, Bruce E Holbein, Christian Lehmann
BACKGROUND: Sepsis is the systemic inflammatory response to an infection. Generation of reactive oxygen species represents an important part of the inflammatory cascade in sepsis. Dysregulation of iron homeostasis can further promote the generation of radicals and amplify the damage caused by systemic immune activation. This can potentially be suppressed or prevented by iron chelation. Therefore, this study was designed to examine the effects of a novel iron chelator (DIBI) with or without standard antibiotic treatment in colon ascendens stent peritonitis (CASP)-induced experimental sepsis...
January 2016: Journal of Surgical Research
Jan-Marten Seitz, Martin Durisin, Jeremy Goldman, Jaroslaw W Drelich
Sutures that biodegrade and dissolve over a period of several weeks are in great demand to stitch wounds and surgical incisions. These new materials are receiving increased acceptance across surgical procedures whenever permanent sutures and long-term care are not needed. Unfortunately, both inflammatory responses and adverse local tissue reactions in the close-to-stitching environment are often reported for biodegradable polymeric sutures currently used by the medical community. While bioabsorbable metals are predominantly investigated and tested for vascular stent or osteosynthesis applications, they also appear to possess adequate bio-compatibility, mechanical properties, and corrosion stability to replace biodegradable polymeric sutures...
September 16, 2015: Advanced Healthcare Materials
Lu Huang, Chao Pu, Richard K Fisher, Deidra J H Mountain, Yanfei Gao, Peter K Liaw, Wei Zhang, Wei He
UNLABELLED: Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility...
October 2015: Acta Biomaterialia
C Setacci, F Speziale, G De Donato, P Sirignano, F Setacci, L Capoccia, G Galzerano, W Mansour
According to the World Health Organization, every year, 5 million peoples die for stroke and another 5 million are permanently disabled. Although there are many causes of acute stroke, a common treatable cause of acute stroke is atheromatous narrowing at the carotid bifurcation. Carotid endarterectomy is still the standard of car, even if carotid artery stenting (CAS) has become an effective, less invasive alterantive. Unfortunately, CAS procedure is not yet perfect; regardless the use of an embolic protection device (EPD), percutaneous treatment has been correlated with a risk of cerebral ischemic events related to distal embolization...
October 2015: Journal of Cardiovascular Surgery
Alexander N Kharlamov, Anastasiya E Tyurnina, Vera S Veselova, Olga P Kovtun, Vladimir Y Shur, Jan L Gabinsky
BACKGROUND: Atheroregression becomes an attractive target for cardiovascular treatment. Some clinical trials have demonstrated that intensive therapy with rosuvastatin or recombinant ApoA-I Milano can partially reduce the total atheroma volume (TAV) up to 6.38 mm(3) or 14.1 mm(3) respectively. Our previous bench studies of selected nanotechnologies documented TAV reduction up to an unprecedented 79.4 mm(3). METHODS: The completed observational three arms (n = 180) first-in-man trial (the NANOM FIM trial) assessed (NCT01270139) the safety and feasibility of two delivery techniques for nanoparticles (NP), and plasmonic photothermal therapy (PPTT)...
May 7, 2015: Nanoscale
Giorgia M Bosi, Claudio Capelli, Sachin Khambadkone, Andrew M Taylor, Silvia Schievano
OBJECTIVES AND BACKGROUND: Patient-specific finite element (FE) simulations were used to assess different transcatheter valve devices and help select the most appropriate treatment strategy for a patient (17-year-old male) with borderline dimensions for Melody® percutaneous pulmonary valve implantation (PPVI). METHODS AND RESULTS: Patient-specific implantation site morphology was derived from cardiovascular magnetic resonance (CMR) images along with the implantation site mechanical behavior by coupling systolic/diastolic dimensions and the pressure gradient in a linear elastic model, and iterative tuning...
November 15, 2015: Catheterization and Cardiovascular Interventions
C A Sweeney, B O'Brien, F P E Dunne, P E McHugh, S B Leen
This paper presents a framework of experimental testing and crystal plasticity micromechanics for high cycle fatigue (HCF) of micro-scale L605 CoCr stent material. Micro-scale specimens, representative of stent struts, are manufactured via laser micro-machining and electro-polishing from biomedical grade CoCr alloy foil. Crystal plasticity models of the micro-specimens are developed using a length scale-dependent, strain-gradient constitutive model and a phenomenological (power-law) constitutive model, calibrated from monotonic and cyclic plasticity test data...
June 2015: Journal of the Mechanical Behavior of Biomedical Materials
Adil Mardinoglu, P J Cregg
Cancer is a leading cause of death worldwide and it is caused by the interaction of genomic, environmental, and lifestyle factors. Although chemotherapy is one way of treating cancers, it also damages healthy cells and may cause severe side effects. Therefore, it is beneficial in drug delivery in the human body to increase the proportion of the drugs at the target site while limiting its exposure at the rest of body through Magnetic Drug Targeting (MDT). Superparamagnetic iron oxide nanoparticles (SPIONs) are derived from polyol methods and coated with oleic acid and can be used as magnetic drug carrier particles (MDCPs) in an MDT system...
2015: TheScientificWorldJournal
Achmad Syaifudin, Ryo Takeda, Katsuhiko Sasaki
The physical properties of the stent surface influence the effectiveness of vascular disease treatment after stent deployment. During the expanding process, the stent acquires high-level deformation that could alter either its microstructure or the magnitude of surface roughness. This paper constructed a finite element simulation to observe the changes in surface roughness during the stenting process. Structural transient dynamic analysis was performed using ANSYS, to identify the deformation after the stent is placed in a blood vessel...
2015: Bio-medical Materials and Engineering
Natalia S Fagali, Claudia A Grillo, Susana Puntarulo, Mónica A Fernández Lorenzo de Mele
Fe-based biodegradable metallic materials (Fe-BMMs) have been proposed for cardiovascular applications and are expected to disappear via corrosion after an appropriate period. However, in vivo studies showed that Fe ions release leads to accumulation of orange and brownish insoluble products at the biomaterial/cell interface. As an additional consequence, sharp changes in pH may affect the biocompatibility of these materials. In the present work, the experimental protocols were designed with the aim of evaluating the relative importance that these factors have on biocompatibility evaluation of BMMs...
April 1, 2015: Colloids and Surfaces. B, Biointerfaces
Tao Huang, Jian Cheng, Dong Bian, Yufeng Zheng
In this study, Fe-Ag and Fe-Au composites were fabricated by powder metallurgy using spark plasma sintering. Their microstructures, mechanical properties, and biocorrosion behavior were investigated by using optical microscopy, X-ray diffraction, environment scanning electronic microscopy, compressive test, electrochemical measurements, and immersion tests. Microstructure characterization indicated that the as-sintered iron-based materials obtained much finer grains than that of as-cast pure iron. Phase analysis showed that the Fe-Ag composites were composed of α-Fe and pure Ag phases, and Fe-Au composites consisted of α-Fe and Au phases...
February 2016: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
A Francis, Y Yang, S Virtanen, A R Boccaccini
In the last decade, biodegradable metals have emerged as a topic of interest for particular biomedical applications which require high strength to bulk ratio, including for cardiovascular stents. The advantages of biodegradable materials are related to the reduction of long term risks associated with the presence of permanent metal implants, e.g. chronic inflammation and in-stent restenosis. From a structural point of view, the analysis of the literature reveals that iron-based alloys used as temporary biodegradable stents have several advantages over Mg-based alloys in terms of ductility and strength...
March 2015: Journal of Materials Science. Materials in Medicine
Camillus Sunday Obayi, Ranna Tolouei, Carlo Paternoster, Stephane Turgeon, Boniface Adeleh Okorie, Daniel Oray Obikwelu, Glenn Cassar, Joseph Buhagiar, Diego Mantovani
Iron-based biodegradable metals have been shown to present high potential in cardiac, vascular, orthopaedic and dental in adults, as well as paediatric, applications. These require suitable mechanical properties, adequate biocompatibility while guaranteeing a low toxicity of degradation products. For example, in cardiac applications, stents need to be made by homogeneous and isotropic materials in order to prevent sudden failures which would impair the deployment site. Besides, the presence of precipitates and pores, chemical inhomogeneity or other anisotropic microstructural defects may trigger stress concentration phenomena responsible for the early collapse of the device...
April 2015: Acta Biomaterialia
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