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|Title: ||Cell mechanical modeling and mechanical properties characterization|
|Other Titles: ||Xi bao li xue jian mo ji qi li xue te xing de biao zheng|
|Authors: ||Tan, Youhua (譚又華)|
|Department: ||Department of Manufacturing Engineering and Engineering Management|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2010|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Cells -- Mechanical properties.|
|Notes: ||CityU Call Number: QH645.5 .T36 2010|
x, 142 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2010.
Includes bibliographical references (leaves 112-136)
|Abstract: ||Cell biomechanics regulate cellular physiological functions, such as locomotion,
cell division, proliferation, mechanotransduction, and cell death. Current research reports
that alterations of the mechanical properties of cells may be associated with the
onset and progression of some diseases. Since mechanical properties are intrinsic to
biological cells, they can be used as biomarkers to (1) investigate property variation,
along with the developmental stages of cells; (2) distinguish normal cells from diseased
ones; and (3) measure the variation of cell properties after treatment by chemicals
or by varying their physiological environments. Several experimental techniques
and computational approaches have been proposed to measure the mechanical responses
of biological cells. However, the study of cell mechanical properties at the
single cell level remains challenging. In particular, there exists an increasing need for
a cell mechanical model for a variety of experimental conditions.
This thesis proposes a new cell mechanical model to predict the mechanical response
of cells during the process of cell manipulation and to characterize cell properties.
This model is based on membrane theory and establishes the relationship between
the imposed force and the induced cell deformation. Different cell properties
correspond to different force-deformation curves. Therefore, by comparing the experimental
data to the modeling results, the mechanical properties of cells can be
characterized. By varying the boundary conditions, the proposed cell model can be
applied in the following aspects.
First, the proposed cell mechanical model is used to describe the deformation behavior
of cells during microinjection. Based on this model, the relationship between
the injection force and the cell deformation can be obtained. To verify the proposed
model, microinjection experiments are performed on zebrafish embryos at different
developmental stages. The experimental data correspond with the modeling results,
which show that the proposed modeling methodology can be utilized to estimate the
mechanical responses of cells. Moreover, the elastic moduli of zebrafish embryos are
characterized, indicating embryos softening along with development before hatching. Furthermore, various constitutive materials are incorporated into the mechanical
model to represent the material behavior of embryos membranes. The most appropriate
material is recognized for a specific biomembrane when the best fitness between
the experimental and modeling results is achieved.
Second, optical tweezers technology is utilized to study the effect of osmotic
condition on the cell properties of human red blood cells (RBCs). The trapping forces
and the cell deformations are obtained through force calibration and image processing,
respectively. To extract the mechanical properties of RBCs, the cell mechanical
model is extended for spherical RBCs, and finite element (FE) analysis is conducted
for biconcave RBCs. Based on the cell modeling methods, shear moduli of RBCs in
different osmotic conditions are characterized, revealing an increase of cell stiffness
with increasing osmolality.
Third, the proposed mechanical model is applied to predict the deformation responses
of RBCs when stretched by two counter-propagating laser beams in an optical
stretcher. Comparison with the experiments reported in the literature reveals that the
modeling results agree with the experimental data, which in turn demonstrates the validity
of our developed model. Furthermore, the mechanical properties of RBCs are
obtained. This study demonstrates that our mechanical model can be used to predict
the deformation response and characterize the cell mechanics of RBCs in the optical
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b3947539|
|Appears in Collections:||MEEM - Doctor of Philosophy |
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