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Laying the foundations for drag reduction using ferrofluids in stent applications

Applicant Holzner Markus
Number 200727
Funding scheme Project funding (Div. I-III)
Research institution Eidgenössische Forschungsanstalt WSL für Wald, Schnee und Landschaft
Institution of higher education Swiss Federal Institute for Forest, Snow and Landscape Research - WSL
Main discipline Fluid Dynamics
Start/End 01.12.2021 - 30.11.2025
Approved amount 522'864.00
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All Disciplines (2)

Discipline
Fluid Dynamics
Biomedical Engineering

Keywords (4)

drag reduction; stent; blood damage; ferrofluids

Lay Summary (German)

Lead
Dieses Projekt soll Reibungsverminderung für medizinischen Stent-Anwendungen mittels Ferrofluiden erzielen.
Lay summary

Dieses Projekt verbindet Prinzipien der Strömungsmechanik und Biomedizintechnik, um eine neue Technologie zur Reduzierung von Stentthrombosen und -restenosen zu entwickeln.

Wir verwenden dafür magnetorheologische Flüssigkeiten, auch Ferrofluide (FF) genannt, die als Gleitmittel zur Reduzierung schädlicher Wandschubspannungen an der Stentoberfläche eingesetzt werden.

Die Ziele des Projekts sind, erstens, die Effektivität verschiedener biokompatibler FF unter unterschiedlichen Scher- und Magnetfeldstärken zu untersuchen, um die besten Fluide für Stents auszuwählen. Zweitens werden wir Widerstandsreduzierung quantifizieren, indem wir umfangreiche FF-beschichtete Rohrströmungsexperimente durchführen. Drittens werden wir die Effizienz der neuartigen Reibungsverminderungs-Technik bei magnetisierten Stents in vitro evaluieren. Schließlich werden wir die Fähigkeit von FFs überprüfen, Blutschäden, Thrombusbildung und die Wahrscheinlichkeit einer Restenose zu mildern.

In diesem Projekt werden Prinzipien der Strömungsmechanik mit Nanotechnologie kombiniert, um unser Verständnis der Physik der Widerstandsreduktion zu verbessern und dies zu nutzen, um die Grundlagen für eine neuartige biomedizinische Anwendung zu schaffen, nämlich Reibungsvermindernde Stents.

Direct link to Lay Summary Last update: 16.11.2021

Lay Summary (English)

Lead
This project aims at laying the foundations for drag reduction in stent applications using ferrofluids. To achieve this, it will develop cutting-edge technology for the reduction of stent thrombosis and restenosis events, based on a multidisciplinary approach linking fluid mechanics and biomedical engineering.
Lay summary
The nanotechnology is based on magnetorheological fluids, also called ferrofluids (FFs), which will be used as a lubricant for the reduction of harmful wall shear stresses generated at the stent surface. The objectives are, firstly, to evaluate the performance in terms of magnetoviscous effects of various biocompatible FFs varying shear and magnetic field strength to select the best candidate FFs for stents. Secondly, we will evaluate the fundamentals of FF-based drag reduction by performing extensive FF-coated pipe flow experiments. Thirdly, we will evaluate the efficiency of the novel drag reduction technique in magnetized stents in vitro. Finally, we will verify the ability of FFs to mitigate blood damages, thrombus formation and the probability of re-stenosis.

In this project, principles of fluid mechanics are combined with nanotechnology to advance our understanding of the physics of drag reduction and exploit this to establish the foundations for a novel biomedical engineering application, namely, the next generation of stents termed Drag Reducing Stents (DRS). The proposed technology strives to complement or even replace adjunctive pharmacological treatments usually adopted after stent implantation, which often have significant harmful side effects. It thus has the potential to improve the quality of life of millions of patients worldwide that undergo coronary stenting each year, and to provide a new solution for patients in which pharmacological therapies cannot be prescribed. More broadly, the project results are also expected to foster other applications of FFs in the bioengineering medical field, e.g. lubricated mechanical heart valves, and to aid the development of new drag reduction techniques applicable in other research areas (e.g., naval sector and oil pipe industries) that seek to reduce energy losses for greener technology.
Direct link to Lay Summary Last update: 16.11.2021

Responsible applicant and co-applicants

Employees

Project partner

Associated projects

Number Title Start Funding scheme
191987 Flow-structure interaction in pulsatile flow 01.11.2019 Project funding (Div. I-III)

Abstract

This project aims at laying the foundations for drag reduction in stent applications using ferrofluids. To achieve this, it will develop cutting-edge technology for the reduction of stent thrombosis and restenosis events, based on a multidisciplinary approach linking fluid mechanics and biomedical engineering. The nanotechnology is based on magnetorheological fluids, also called ferrofluids (FFs), which will be used as a lubricant for the reduction of harmful wall shear stresses generated at the stent surface. The objectives are, firstly, to evaluate the performance in terms of magnetoviscous effects of various biocompatible FFs varying shear and magnetic field strength to select the best candidate FFs for stents. Secondly, we will evaluate the fundamentals of FF-based drag reduction by performing extensive FF-coated pipe flow experiments. Thirdly, we will evaluate the efficiency of the novel drag reduction technique in magnetized stents in vitro. Finally, we will verify the ability of FFs to mitigate blood damages, thrombus formation and the probability of re-stenosis.Work package (WP) 1 will use microfluidics to investigate the rheology of biocompatible ferrofluids as a function of shear rate and ferrofluid magnetization rate and relate it to FF structure at the microscale, i.e. the magnetite chain characteristics. This will allow understanding the FF behavior at the ferrofluid-blood interface and selecting the most promising FF types for drag reduction. In WP2, we will conduct pressure transducer- and high speed imaging-based velocity measurements in FF-coated pipe flow to quantify drag reduction over a wide range of shear and magnetic field strengths. We will investigate key factors such as the viscosity ratio between the ferrofluid and the inner fluid and turbulence. Based on this fundamental understanding, in WP3 we address the drag reduction performance of FFs in stents. First, we will conduct flow visualization and velocity measurements using a simplified stent model to verify that stent struts’ lubrication is effective and recirculation zones in their lee side are suppressed. Second, we evaluate drag reduction in real FF-coated stents in vitro using pressure readings. In the final WP4 we examine the efficiency of the proposed approach with real blood in vitro by comparing FF coated stents with uncoated ones. Secondly, we will investigate possible biocompatibility issues related to the FF biochemical environment and other physical forces (i.e. electrostatic, surface tension).In this project, principles of fluid mechanics are combined with nanotechnology to advance our understanding of the physics of drag reduction and exploit this to establish the foundations for a novel biomedical engineering application, namely, the next generation of stents termed Drag Reducing Stents (DRS). The proposed technology strives to complement or even replace adjunctive pharmacological treatments usually adopted after stent implantation, which often have significant harmful side effects. It thus has the potential to improve the quality of life of millions of patients worldwide that undergo coronary stenting each year, and to provide a new solution for patients in which pharmacological therapies cannot be prescribed. More broadly, the project results are also expected to foster other applications of FFs in the bioengineering medical field, e.g. lubricated mechanical heart valves, and to aid the development of new drag reduction techniques applicable in other research areas (e.g., naval sector and oil pipe industries) that seek to reduce energy losses for greener technology.
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