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|Title: ||Towards automatic batch biomanipulation : study on robotic suspended cell injection system|
|Other Titles: ||Mian xiang da pi liang zi dong hua sheng wu zhi zao de ji xie xuan fu xi bao zhu she xi tong yan jiu|
|Authors: ||Huang, Haibo (黃海波)|
|Department: ||Department of Manufacturing Engineering and Engineering Management|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2008|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Manipulators (Mechanism) -- Automatic control.|
Robots, Industrial -- Automatic control.
Injections -- Microbiology.
|Notes: ||x, 121 leaves : ill. 30 cm.|
Thesis (Ph.D.)--City University of Hong Kong, 2008.
Includes bibliographical references (leaves 102-116)
CityU Call Number: TJ211 .H83 2008
|Abstract: ||Biological cell injection has been widely applied in gene injection, in-vitro fertilization,
intracytoplasmic sperm injection and drug development. The cells injected in
biotechnology are classified as either adherent or suspended cells, corresponding to two
distinct biomanipulation tasks. Currently, commercial devices are available for
automation of adherent cell injection tasks. In contrast, development of methodologies for
injection of suspended cells, has been the focus of many research groups.
In this study, a cell injection system for automatic batch injection of suspended cells is
developed. The suspended cells are held and fixed to a cell array by a specially designed
cell holding device, which enables automatic injection of batch of suspended cells.
Starting from image identifying the embryos and injector pipette, a proper batch cell
injection process, including the injection trajectory of the pipette, is designed for this
automatic suspended cell injection system. Based on those preparative works, two kinds
of methodologies were developed to enhance the performance of cell injection.
The first methodology is to regulate cell injection forces using geometry of cell
deformations and micro vision feedback. The microscope vision system, which is already
present in the biomanipulation system, is utilized to measure cell deformations, further to
estimate the cell injection forces, based on a cell biomembrane point-load model. In outof-
plane injection process, the total cell membrane deformation is estimated, based on the
X −Y coordinate frame deformation of the cell, as measured with microscope, and the
known angle between the injector and the X −Y plane. Further, a relationship between
the injection force and the injector displacement of the cell membrane, as observed with
the camera, is derived. Based on this visual force estimation scheme, an impedance
injection force controller is developed to control the injection process. Although this visual-based force control method only utilizes the microscope for not adding complexity
to this system, the limitation of the proposed approach is that the injector can only be
imaged from above in depth direction, and hence the actual penetration distance into the
cell, depending on the vertical position of the injector with respect to the insertion point
on the cell, cannot be known.
To solve this problem, in the second method, it is demonstrated that the motion of the
injector pipette can be controlled through integration of a polyvinylidene fluoride (PVDF)
film micro force sensor installed on the injection pipette to the visual control system. This
force sensor is utilized to measure the real time injection force applied to the cells with a
sensitivity of 0.1901mV /μN . The out-of-plane cell injection task can be decoupled into
two relatively independent control processes: the position control in the X −Y horizontal
plane and the impedance control in Z − axis. In X −Y plane, a computed torque based
position control with visual feedback is used. The purpose is to accurately control the
injector pipette to follow the desired injection trajectory in X −Y plane. Based on the
measured injector position in X −Y plane and the calibrated relationship between the
injection trajectory and force, the desired injection force in Z − axis at the moment can be
determined according to the available cell deformation in X −Y plane. Utilizing this
desired force, an impedance control algorithm is developed to control the injection force
to follow the desired value and thus indirectly control the depth motion of the injector
pipette in Z − axis.
This research provides a systematic solution for automation of batch suspended cell
injection. The proposed visual control methodologies have potential prospects not only in
inserting genetic materials into embryos, but also in general biomanipulation tasks. The
research outputs will eventually benefit the biotechnology industry and release people
from laborious works.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2268739|
|Appears in Collections:||MEEM - Doctor of Philosophy |
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