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|Title: ||Study for cell positioning and cell-to-cell interactions with robot-tweezer manipulation system|
|Other Titles: ||Ying yong ji qi ren fu zhu guang nie ji shu yan jiu xi bao ding wei ji xi bao jian xiang hu zuo yong|
|Authors: ||Hu, Songyu ( 胡松鈺)|
|Department: ||Department of Mechanical and Biomedical Engineering|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2011|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Optical tweezers.|
Cells -- Motility.
|Notes: ||CityU Call Number: TK8360.O67 H8 2011|
x, 87 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2011.
Includes bibliographical references (leaves 76-85)
|Abstract: ||Transportation and positioning of biological cells has become increasingly
important in contemporary biomedical research. A significant demand for both
accuracy and productivity in cell positioning highlights the need for automated cell
transportation with integrated robotics and micro/nano manipulation technologies.
Most of the existing methods for studying cell-to-cell interactions are based on a large
number of cells and a sufficient quantity of analytes, which unfortunately lose
heterogenous information of individual cells. Techniques which can be used to study
cell-to-cell adhesive interaction at the single-cell level are needed. In this study, a
robot-tweezer manipulation system for automatically positioning biological cells is
investigated, which enables further research on cell-to-cell interactions between
leukemia cells and bone marrow stromal cells. This thesis study includes the
following three aspects.
First, a new approach is proposed to incorporating robotics technologies into optical
tweezers for automated transportation of biological cells. A robot-tweezer
manipulation system is proposed. Dynamics of the cells in optical trapping is analyzed.
Cell motion in the x-y plane is mainly governed by the trapping force of the optical
trap and viscous drag force of the liquid. After discussion of these two forces,
theoretically, the dynamics of the trapped cell is reduced to a constrained first-order
system. A control algorithm for single-cell positioning is developed with micro/nano
precision, which enables the robot-tweezer system to position biological cells rapidly
Second, a synchronization controller is developed by utilizing the cross-coupling
approach, which can be used to address the multi-cell transportation problem.
Synchronous transportation of multiple cells while maintaining their original pattern is necessary in a variety of bioapplications, such as steady transportation of large
arrays of cells for simultaneous cellular assays in parallel, undisturbed positioning of
cell body" connected with cell-to-cell channels, movement of artificial biological
tissues fabricated with multiple cells, and so on. The basic idea of the proposed
control research is that multiple cells track each desired trajectory individually while
synchronizing motions amongst each other to maintain the required multi-cell pattern.
Simulation and experiments performed on transporting yeast cells and T cells while
maintaining their required shape patterns demonstrate the effectiveness of the
Third, the robot-tweezer manipulation system is used to study the cell-to-cell
adhesive interactions. Elucidation of the mechanism of leukemia cell adhesion to
stroma and the adhesion mediated interactions contributing to leukemia initiation and
progression may provide a promising new paradigm for development of specific
targeted therapies. Cell-to-cell adhesive interactions between leukemia cells and bone
marrow stromal cells are studied using the proposed approach. To demonstrate the
feasibility of this approach, the viability of leukemia cells after optical trapping is
tested and verified. Adhesion properties of leukemia cells on bone stromal cells are
then characterized. Adhesion ability of leukemia cells on stromal cells is reduced by
As2O3 and AMD3100 or by heparin, which preliminarily demonstrate the specificity
and mechanism of the adhesion.
In summary, the proposed robot-tweezer manipulation system and enabled closedloop
control technology provide a novel solution for positioning single/multiple cells
rapidly and precisely, which exhibits much biological relevance in cell-to-cell
interaction, drug discovery and tissue engineering. The study of leukemia-stromal
adhesive interactions provides insight into understanding interactions between
leukemia and stromal cells, which helps further with providing specific targets for
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b4086930|
|Appears in Collections:||MBE - Doctor of Philosophy|
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