Browsing by Author "Shih, Po-Chen"

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Fabrication of 3D Microfluidic Chip integrating Concentration gradient design and Perfusion system for Embryo coculture with Stromal cells
(2012-01-01)
Chang, Pei-Yu
;
Chang, Kuo-Wei
;
Lin, Ciou-Wen
;
Shih, Po-Chen
;
Liu, Cheng-Hsien
Fabrication of 3D chip that enables cell culture under continuous flow perfusion and repeated in situ observation by light microscopy is described. Thin polydimethylsiloxane PDMS) membrane was etched to create an array of through-holes, and sandwiched between two PDMS channels to form an upper chamber and lower chamber. Thus we fabricated a 3D microfluidic chip which integrates the concentration gradient design and perfusion system for proposed embryo coculture with stromal cells.
Finger-powered agglutination lab chip with CMOS image sensing for rapid point-of-care diagnosis applications
(2020-01-21)
Lu, Chung Hsiang
;
Shih, Ting-Sheng
;
Shih, Po-Chen
;
Pendharkar, Gaurav Prashant
;
Liu, Cheng-En
Agglutination is an antigen-antibody reaction with visible expression of aggregation of the antigens and their corresponding antibodies. Applications extend to the identification of acute bacterial infection, hemagglutination, such as blood grouping, and diagnostic immunology. Our finger-powered agglutination lab chip with external CMOS image sensing was developed to support a platform for inexpensive, rapid point-of-care (POC) testing applications related to agglutination effects. In this paper, blood grouping (ABO and Rh grouping) was utilized to demonstrate the function of our finger-powered agglutination lab chip with CMOS image sensing. Blood antibodies were preloaded into the antibody reaction chamber in the lab chip. The blood sample was pushed through the antibody reaction chamber using finger-powered pressure actuation to initiate a hemagglutination reaction to identify the blood type at the on-chip detection area using our homemade CMOS image sensing mini-system. Finger-powered actuation without the need for external electrical pumping is excellent for low-cost POC applications, but the pumping liquid volume per finger push is hard to control. In our finger-powered agglutination lab chip with CMOS image sensing, we minimized the effects of different finger push depths and achieved robust performance for the test results with different push depths. The driving sample volume per finger push is about 0.79 mm(3). For different chips and different pushes, the driven sample volume per finger push was observed to vary in the range of 0.64 to 1.18 mm(3). The red blood cells were separated from the plasma on-chip after the whole blood sample was finger pumped and before the red blood cells reached the antibody chamber via an embedded plasma-separation membrane. Our homemade CMOS image mini-system robustly read and identified the agglutination results on our agglutination lab chip.
Measurement of macrophage adhesion by optical tweezers with backward-scattered detection
(2010)
Wei, Sung-Yang
;
Su, Yi-Jr
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Shih, Po-Chen
;
Yang, Shih-Mo
;
Hsu, Long
Macrophages are members of the leukocyte family. Tissue damage causes inflammation and release of vasoactive and chemotactic factors, which trigger a local increase in blood flow and capillary permeability. Then, leukocytes accumulate quickly to the infection site. The leukocyte extravasation process takes place according to a sequence of events that involve tethering, activation by a chemoattractant stimulus, adhesion by integrin binding, and migrating to the infection site. The leukocyte extravasation process reveals that adhesion is an important part of the immune system. Optical tweezers have become a useful tool with broad applications in biology and physics. In force measurement, the trapped bead as a probe usually uses a polystyrene bead of 1 mu m diameter to measure adhesive force between the trapped beads and cell by optical tweezers. In this paper, using the ray-optics model calculated trapping stiffness and defined the linear displacement ranges. By the theoretical values of stiffness and linear displacement ranges, this study attempted to obtain a proper trapped particle size in measuring adhesive force. Finally, this work investigates real-time adhesion force measurements between human macrophages and trapped beads coated with lipopolysaccharides using optical tweezers with backscattered detection.