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A comparison of mechanical models for the viscoelastic response of human breast carcinomas

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dc.contributorUnnikrishnan, Vinu U.
dc.contributorTodd, Beth A.
dc.contributor.advisorMahmoodi, S. Nima
dc.contributor.authorCarmichael, Benjamin Daniel
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2017-03-01T17:11:35Z
dc.date.available2017-03-01T17:11:35Z
dc.date.issued2014
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractThe mechanical response of a living cell is notoriously complicated. The complex, heterogeneous characteristics of cellular structure introduce difficulties that simple linear models of viscoelasticity cannot overcome, particularly at moderate indentation depths. Herein, a nano-scale stress-relaxation analysis performed with an Atomic Force Microscope reveals that isolated human breast cells do not exhibit simple exponential relaxation capable of being modeled by the Standard Linear Solid (SLS) model. Therefore, this work proposes the application of a progression of more sophisticated models that may extract the mechanical parameters from the entire relaxation response, improving upon existing physical techniques to probe isolated cells. The first model under consideration is the Generalized Maxwell (GM) model that distributes the response of the cell across multiple time scales in an attempt to replicate the interaction of subcellular components. The second is a fractional model that operates without a priori assumptions of the cell's internal structure and describes the fractional time-derivative dependence of the response. The results show an exceptional increase in conformance to the experimental data compared to that predicted by the SLS model. Both models excel at mapping the relaxation behavior of the cells that occurs within a few seconds of the initial force. This area is generally ignored with an SLS fit and therefore not included in most cell differentiation studies. The results of the GM model show a significant change in the mechanical properties of the first relaxation mode, which validates the necessity of the early behavior's inclusion. The FZ model preserves the distinctions highlighted in the SLS model, but also incorporates the disparity in the early-relaxation times seen in the GM model as a change in the composite relaxation time.en_US
dc.format.extent62 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0001714
dc.identifier.otherCarmichael_alatus_0004M_12147
dc.identifier.urihttps://ir.ua.edu/handle/123456789/2164
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectBiomechanics
dc.subjectMechanics
dc.titleA comparison of mechanical models for the viscoelastic response of human breast carcinomasen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Mechanical Engineering
etdms.degree.disciplineMechanical Engineering
etdms.degree.grantorThe University of Alabama
etdms.degree.levelmaster's
etdms.degree.nameM.S.

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