2026-09-19T06:32:45Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/1327392025-10-30T17:03:45Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023

Lydia Bourouiba and Thomas Heldt. Lee, Sungkwon(Mechanical engineer)Massachusetts Institute of Technology. Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2021-10-06T19:56:56Z 2021-10-06T19:56:56Z 2019 2019 https://hdl.handle.net/1721.1/132739 1263579857 Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, 2019 Cataloged from the PDF version of thesis. Includes bibliographical references (pages 75-81). The ventricular catheter for treatment of hydrocephalus has a low lifespan due to obstruction by brain tissue. Multiple catheter designs have been proposed, but breakthroughs have not been made yet particularly due to the lack of understanding of the obstruction mechanisms that appear to be coupled with the fluid dynamics of ventricular catheters and cerebrospinal fluid (CSF). Recent studies have shown that glial tissue, which is mainly comprised of astrocytes, is the major contributor to obstruction. Impeding glial tissue formation should then be the foremost goal of the next-generation catheter, which leaves a crucial question that has not been answered yet: How does the fluid dynamics of ventricular catheters affect glial tissue formation? Answering this question, this thesis suggests a new design objective based on in vitro microfluidic experiments on astrocytes and proposes a novel design scheme developed on a lumped-element model describing the fluid dynamics of ventricular catheters. The thesis conducted long-term in vitro microfluidic culture of astrocytes and showed that fluid shear stress inhibits astrocytes from increasing confluency and reduces their viability. In light of the result, using Computational Fluid Dynamics (CFD) simulations, we showed that the conventional geometry of ventricular catheters is vulnerable to astrocytes ingrowth. To find improved catheter geometries, we performed a numerical optimization based on a lumped-element model. We validated the lumped-element model against CFD simulations also in good agreement with the direct flow visualization we performed in the actual catheters. Apart from flow analysis, CSF was investigated, determining its range of surface tension and showing it to be shear thinning at low shear rates. Finally, we propose a new design paradigm for more robust catheters for hydrocephalus patients. by Sungkwon Lee. S.M. S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering 88 pages eng Massachusetts Institute of Technology MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. Flow optimization of ventricular catheters for shear stress-induced death of astrocytes Thesis application/pdf 2021-10-06T19:56:56Z Publication Master MechE unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="d94c96d8-2ca3-4dd0-a81f-e646a28e8d1b"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Flow optimization of ventricular catheters for shear stress-induced death of astrocytes</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2019</PublicationDate> <Authors> <Author> <DisplayName>Lee, Sungkwon(Mechanical engineer)Massachusetts Institute of Technology.</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>The ventricular catheter for treatment of hydrocephalus has a low lifespan due to obstruction by brain tissue. Multiple catheter designs have been proposed, but breakthroughs have not been made yet particularly due to the lack of understanding of the obstruction mechanisms that appear to be coupled with the fluid dynamics of ventricular catheters and cerebrospinal fluid (CSF). Recent studies have shown that glial tissue, which is mainly comprised of astrocytes, is the major contributor to obstruction. Impeding glial tissue formation should then be the foremost goal of the next-generation catheter, which leaves a crucial question that has not been answered yet: How does the fluid dynamics of ventricular catheters affect glial tissue formation? Answering this question, this thesis suggests a new design objective based on in vitro microfluidic experiments on astrocytes and proposes a novel design scheme developed on a lumped-element model describing the fluid dynamics of ventricular catheters. The thesis conducted long-term in vitro microfluidic culture of astrocytes and showed that fluid shear stress inhibits astrocytes from increasing confluency and reduces their viability. In light of the result, using Computational Fluid Dynamics (CFD) simulations, we showed that the conventional geometry of ventricular catheters is vulnerable to astrocytes ingrowth. To find improved catheter geometries, we performed a numerical optimization based on a lumped-element model. We validated the lumped-element model against CFD simulations also in good agreement with the direct flow visualization we performed in the actual catheters. Apart from flow analysis, CSF was investigated, determining its range of surface tension and showing it to be shear thinning at low shear rates. Finally, we propose a new design paradigm for more robust catheters for hydrocephalus patients.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>