Attachment and Detachment of Circulating Tumor Cells in an Antibody-Functionalized Microsystem

Persistent Link:
http://hdl.handle.net/10150/195478
Title:
Attachment and Detachment of Circulating Tumor Cells in an Antibody-Functionalized Microsystem
Author:
Cheung, Siu Lun
Issue Date:
2009
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The attachment and detachment of circulating tumor cells in a functionalized microchannel under hydrodynamic loading have been studied. For the cell attachment experiments, EpCAM antibodies are immobilized on the microchannel surface to capture either PC3N prostate or MDA-MB-231 breast cancer cells from homogeneous cell suspensions. Using the same protocol, N-Cadherin antibodies are immoblilzed and used to study the detachment of target cancer cells captured in the microchannels.A critical flow rate Qc has been identified to characterize the kinetics of cell capture in a functionalized microchannel. Approaching one limit, when the receptor-ligand interaction dominates, more than 90% of moving cells can be captured and a sharp peak is observed in the spatial distribution of the captured cells. Approaching another limit, when hydrodynamic loading dominates, almost all cells cannot be captured in the channel. Between these two limits, there is a transition region in which both capture efficiency and cell distribution are sensitive to the flow parameters. Proper characteristic time and length scales have been identified to describe the cell spatial distribution using a log-normal statistical model. The kinetic details of cell capture are determined by the competition between the flow rate and the ligand-receptor association/dissociation rates.Additionally, the attachment dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading has been explored. The target cells initially role along the microchannel with fluctuating velocity prior to firm adhesion. When a successful bond is established, the cancer cells require a certain length to come to a complete stop; this stopping length is found to depend linearly on the applied hydrodynamic flow rate. The force balance in the vertical cross stream direction is dominated by the gravitational force; as a result, all cells loaded into a microchannel intimately contact the functionalized channel bottom surface within a short time. The streamwise horizontal motion of the cells on the surface is dominated by the balance between the shear flow hydrodynamic loading and the receptor-ligand binding interaction. A linear spring element is incorporated in the physical model to represent the dynamics of a cancer cell captured by immobilized antibodies. Featuring a mobility matrix, a proposed theoretical model is utilized to estimate the binding and hydrodynamic forces acting on the cell in a microchannel. Inserting certain fitting parameters, the time evolution of a stopping cell is successfully predicted by a simplified exponential function.The mechanical response of a captured cancer cell to a hydrodynamic flow field is investigated and, in particular, the effect of flow acceleration is examined. The observed cell deformation is dramatic under low acceleration, but is negligible under high acceleration. Consequently, the detachment of captured cells depends on both flow rate and flow acceleration. The flow rate required for cell detachment is a random variable that can be described by a log-normal distribution. Two flow acceleration limits have been identified for proper scaling of the flow rate required to detach captured cells. A time constant on the order of 1min for the mechanical response of a captured cell has been identified for scaling the flow acceleration. Based on these acceleration limits and the time constant, an exponential-like empirical model is proposed to predict the flow rate required for cell detachment as a function of flow acceleration.
Type:
text; Electronic Dissertation
Keywords:
Antibody coating; Attachment; Circulating tumor cells; Detachment; Microchannel; Viscoelastic
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Mechanical Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Zohar, Yitshak
Committee Chair:
Zohar, Yitshak

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleAttachment and Detachment of Circulating Tumor Cells in an Antibody-Functionalized Microsystemen_US
dc.creatorCheung, Siu Lunen_US
dc.contributor.authorCheung, Siu Lunen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe attachment and detachment of circulating tumor cells in a functionalized microchannel under hydrodynamic loading have been studied. For the cell attachment experiments, EpCAM antibodies are immobilized on the microchannel surface to capture either PC3N prostate or MDA-MB-231 breast cancer cells from homogeneous cell suspensions. Using the same protocol, N-Cadherin antibodies are immoblilzed and used to study the detachment of target cancer cells captured in the microchannels.A critical flow rate Qc has been identified to characterize the kinetics of cell capture in a functionalized microchannel. Approaching one limit, when the receptor-ligand interaction dominates, more than 90% of moving cells can be captured and a sharp peak is observed in the spatial distribution of the captured cells. Approaching another limit, when hydrodynamic loading dominates, almost all cells cannot be captured in the channel. Between these two limits, there is a transition region in which both capture efficiency and cell distribution are sensitive to the flow parameters. Proper characteristic time and length scales have been identified to describe the cell spatial distribution using a log-normal statistical model. The kinetic details of cell capture are determined by the competition between the flow rate and the ligand-receptor association/dissociation rates.Additionally, the attachment dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading has been explored. The target cells initially role along the microchannel with fluctuating velocity prior to firm adhesion. When a successful bond is established, the cancer cells require a certain length to come to a complete stop; this stopping length is found to depend linearly on the applied hydrodynamic flow rate. The force balance in the vertical cross stream direction is dominated by the gravitational force; as a result, all cells loaded into a microchannel intimately contact the functionalized channel bottom surface within a short time. The streamwise horizontal motion of the cells on the surface is dominated by the balance between the shear flow hydrodynamic loading and the receptor-ligand binding interaction. A linear spring element is incorporated in the physical model to represent the dynamics of a cancer cell captured by immobilized antibodies. Featuring a mobility matrix, a proposed theoretical model is utilized to estimate the binding and hydrodynamic forces acting on the cell in a microchannel. Inserting certain fitting parameters, the time evolution of a stopping cell is successfully predicted by a simplified exponential function.The mechanical response of a captured cancer cell to a hydrodynamic flow field is investigated and, in particular, the effect of flow acceleration is examined. The observed cell deformation is dramatic under low acceleration, but is negligible under high acceleration. Consequently, the detachment of captured cells depends on both flow rate and flow acceleration. The flow rate required for cell detachment is a random variable that can be described by a log-normal distribution. Two flow acceleration limits have been identified for proper scaling of the flow rate required to detach captured cells. A time constant on the order of 1min for the mechanical response of a captured cell has been identified for scaling the flow acceleration. Based on these acceleration limits and the time constant, an exponential-like empirical model is proposed to predict the flow rate required for cell detachment as a function of flow acceleration.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAntibody coatingen_US
dc.subjectAttachmenten_US
dc.subjectCirculating tumor cellsen_US
dc.subjectDetachmenten_US
dc.subjectMicrochannelen_US
dc.subjectViscoelasticen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMechanical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorZohar, Yitshaken_US
dc.contributor.chairZohar, Yitshaken_US
dc.contributor.committeememberWong, Pak Kinen_US
dc.contributor.committeememberWu, Xiaoyien_US
dc.identifier.proquest10610en_US
dc.identifier.oclc659752376en_US
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