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Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention. J Vis Exp 2015 Sep 18(103) PMID: 26436434 PMCID: PMC4692619

Pubmed ID

26436434

DOI

10.3791/53100

Abstract

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing.

Author List

Uthamaraj S, Tefft BJ, Hlinomaz O, Sandhu GS, Dragomir-Daescu D

Author

Brandon J. Tefft PhD Assistant Professor in the Biomedical Engineering department at Medical College of Wisconsin




Scopus

2-s2.0-84942866501   6 Citations

MESH terms used to index this publication - Major topics in bold

Animals
Computer-Aided Design
Cytological Techniques
Endothelial Cells
Equipment Design
Finite Element Analysis
Magnetics
Magnetite Nanoparticles
Magnets
Stents
Swine
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