Browsing by Author "Yang, Shih-Mo"

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A microfluidic chip with a U-shaped microstructure array for multicellular spheroid formation, culturing and analysis
(2014-03-01)
Fu, Chien-Yu
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Tseng, Sheng-Yang
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Yang, Shih-Mo
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Hsu, Long
;
Liu, Cheng-Hsien
Multicellular spheroids (MCS), formed by self-assembly of single cells, are commonly used as a three-dimensional cell culture model to bridge the gap between in vitro monolayer culture and in vivo tissues. However, current methods for MCS generation and analysis still suffer drawbacks such as being labor-intensive and of poor controllability, and are not suitable for high-throughput applications. This study demonstrates a novel microfluidic chip to facilitate MCS formation, culturing and analysis. The chip contains an array of U-shaped microstructures fabricated by photopolymerizing the poly(ethylene glycol) diacrylate hydrogel through defining the ultraviolet light exposure pattern with a photomask. The geometry of the U-shaped microstructures allowed trapping cells into the pocket through the actions of fluid flow and the force of gravity. The hydrogel is non-adherent for cells, promoting the formation of MCS. Its permselective property also facilitates exchange of nutrients and waste for MCS, while providing protection of MCS from shearing stress during the medium perfusion. Heterotypic MCS can be formed easily by manipulating the cell trapping steps. Subsequent drug susceptibility analysis and long-term culture could also be achieved within the same chip. This MCS formation and culture platform can be used as a micro-scale bioreactor and applied in many cell biology and drug testing studies.
A novel optoelectrofulidic system for cells/particles manipulation and sorting
(2010)
Yang, Shih-Mo
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Yu, Tung-Ming
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Huang, Hang-Ping
;
Hsu, Long
;
Liu, Cheng-Hsien
A novel optoelectrofulidic system integrated optical image concentration and alignment system, dielectrophoresis phenomenon, microfluidic and friendly real-time control interface is first reported in this article. A new application of photoconductive material oxotitanium phthalocyanine (TiOPc) for microparticle applying has been first described and demonstrated by our research group. Basis on the special character of the photoconductive material, a TiOPc-based optoelectronic tweezers (Ti-OET) is utilized for single and massive cells/particles manipulation. The objects wanted to be manipulated are defined with different behaviors (e.g., press, release, drag and move) using Flash (R) software when the cursor acts on them. It also reveals the application for biological application to form the cells trapping with three sorts of cells, HMEC-1, HepG2 and HEK293t. Another application of our optoelectrofulidic system is to fabricate a TiOPc-based flow cytometry chip which can be used for sorting the 15 mu m diameter particles with 105 mu m/s velocity. When the 10Vp. p. voltage and 45 kHz AC frequency apply on the top and button ITO electrode, the illuminated light pattern will become a spatially virtual switch inside the microchannel. The dielectrophoresis force between top ITO glass and button photoconductive layer controlled by the friendly interface will concentrate the cells/particles as a straight line and individually direct each one in different paths. In summary, we have established an optoelectronfulidic-based chip and spatially virtual switch system which are applied for cell pattern and particles sorting. In the future, this easy manipulation approach can place the full power of optoelectronfulidic chip into the biological operators' hands.
Cell patterning via diffraction-induced optoelectronic dielectrophoresis force on an organic photoconductive chip
(2013)
Yang, Shih-Mo
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Tseng, Sheng-Yang
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Chen, Hung-Po
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Hsu, Long
;
Liu, Cheng-Hsien
A laser diffraction-induced dielectrophoresis (DEP) phenomenon for the patterning and manipulation of individual HepG2 cells and polystyrene beads via positive/negative DEP forces is reported in this paper. The optoelectronic substrate was fabricated using an organic photoconductive material, TiOPc, via a spin-coating process on an indium tin oxide glass surface. A piece of square aperture array grid grating was utilized to transform the collimating He-Ne laser beam into the multi-spot diffraction pattern which forms the virtual electrodes as the TiOPc-coating surface was illuminated by the multi-spot diffraction light pattern. HepG2 cells were trapped at the spot centers and polystyrene beads were trapped within the dim region of the illuminated image. The simulation results of light-induced electric field and a Fresnel diffraction image illustrated the distribution of trapped microparticles. The HepG2 morphology change, adhesion, and growth during a 5-day culture period demonstrated the cell viability through our manipulation. The power density inducing DEP phenomena, the characteristics of the thin TiOPc coating layer, the operating ac voltage/frequency, the sandwiched medium, the temperature rise due to the ac electric fields and the illuminating patterns are discussed in this paper. This concept of utilizing laser diffraction images to generate virtual electrodes on our TiOPc-based optoelectronic DEP chip extends the applications of optoelectronic dielectrophoretic manipulation.
Concentration of Magnetic Beads Utilizing Light-Induced Electro-Osmosis Flow
(2011-10-01)
Yang, Shih-Mo
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Harishchandra, Punde Tushar
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Yu, Tung-Ming
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Liu, Ming-Huei
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Hsu, Long
Magnetic beads are widely utilized for separating biomolecules, DNA and RNA. Traditionally, bulk magnet is utilized for manipulation these particles but when it comes to microscale bulk magnet is not the efficient method. Here, we utilize an organic photoconductive material, TiOPc, to generate light-induced electro-osmosis flow on chip. The fabrication process is convenient to be handled by the researchers and biologists without cleanroom IC fabrication facility. When specifically designed light pattern is projected onto the TiOPc substrate, the conductivity of the organic material layer within the illuminating region increases and the charges are locally assembled on its surface to form a virtual electrode. With an external ac voltage of 5 Vpp at 10 kHz, numerous magnetic beads are attracted from the nonilluminating region toward the center of light-pattern illuminating region. Driven by the moving light image, the grouped magnetic beads can be manipulated and merged in a desired way or direction. The light manipulation process provides a flexible and convenient approach for in vitro control of magnetic beads. We expect that this light-driven technology would display a multifunctional platform for manipulation of microparticles.
DIELECTROPHORETIC CONCENTRATOR FOR ENHANCED PERFORMANCE OF POLY-SILICON NANOWIRE FIELD EFFECT TRANSISTOR FOR BIOSENSING APPLICATION
(2012)
Puttaswamy, Srinivasu Valagerahally
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Su, Yi-, Jr.
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Sivashankar, Shilpa
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Yang, Shih-Mo
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Yang, Yuh-Shyong
Biological and medical fields have authenticated stupendous advancement in the development of biosensors and biochips. The development of highly sensitive biological sensors is need of the hour. This research work utilizes the dielectrophoretic concentrator chip with titanium (Ti) electrodes to shape the electric field, to pre-concentrate deoxyribo nucleic acid (DNA) within microfluidic channel onto nanowire region of poly-silicon nanowire field effect transistor (poly-Si NWFET). Preconcentration of biomolecules at the constriction site was demonstrated by focusing the DNA with negative dielectrophoresis (nDEP) manipulation technique. After integrating the DEP device with poly-Si NWFET, the I-V-G curve was plotted to ensure n-type behavior.
Dynamic manipulation and patterning of microparticles and cells by using TiOPc-based optoelectronic dielectrophoresis
(2010-06-15)
Yang, Shih-Mo
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Yu, Tung-Ming
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Huang, Hang-Ping
;
Ku, Meng-Yen
;
Hsu, Long
We develop light-driven optoelectronic tweezers based on the organic photoconductive material titanium oxide phthalocyanine. These tweezers function based on negative dielectrophoresis (nDEP). The dynamic manipulation of a single microparticle and cell patterning are demonstrated by using this light-driven optoelectronic DEP chip. The adaptive light patterns that drive the optoelectronic DEP onchip are designed by using Flash software to approach appropriate dynamic manipulation. This is also the first reported demonstration, to the best of our knowledge, for successfully patterning such delicate cells from human hepatocellular liver carcinoma cell line HepG2 by using any optoelectronic tweezers. (C) 2010 Optical Society of America
EMULATED CIRCULATORY SYSTEM INTEGRATED WITH LOBULE-MIMETIC LIVER TO ENHANCE THE LIVER FUNCTION
(2012)
Sivashankar, Shilpa
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Puttaswamy, Srinivasu Valagerahally
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Dai, Tz-Shuian
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Lin, Ciou-Wun
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Yang, Shih-Mo
In the proposed paper, we report dielectrophoresis (DEP) liver lab chip integrated with Poly ethylene glycol diacrylate (PEGDA) based blood vessel within the microfluidic system for reconstructing the engineered liver tissue with the feature of liver function enhancement. The titanium (Ti) electrodes are well designed to provide positive dielectrophoresis (pDEP) and negative dielectrophoresis (nDEP) force to pattern HepG2 and 3T3 fibroblast cells. To mimic the blood flow direction of the liver lobule in vivo, we have integrated the reconstructed liver lobule with hydrogel encapsulated blood vessel. As smooth muscle cells and endothelial cells are the main components of blood vessel, we have utilized these cells and encapsulated within PEGDA hydrogel to mimic blood vessels. When assayed for urea concentration in cultured medium for five time points, the trend illustrated the enhanced metabolism of hepatocytes via blood vessel integrated lobule-mimetic pattern.
Fabrication of PEG Hydrogel Microstructures in Microfluidic System for Multicellular Spheroid Formation, Culturing and Analysis
(2011)
Fu, Chien-Yu
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Tseng, Sheng-Yang
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Yang, Shih-Mo
;
Hsu, Long
;
Liu, Cheng-Hsien
This study presents a novel microfluidic device for 3 dimension cell culturing and analysis. Through defining the exposure to ultra-violet light by a photomask, localized photopolymerization of poly (ethylene glycol) diacrylate hydrogels form biocompatible and permselective microstructures within a microfluidic device. The designed geometry of microstructures allowed cells to be trapped into structures and to form spheroids in situ. Subsequent analysis and long-term three-dimension cell culture can achieve within the same device. This technique may apply as a microscale bioreactor or a platform for spheroid-based drug screening and study.
Integration of organic opto-electrowetting and poly(ethylene) glycol diacrylate (PEGDA) microfluidics for droplets manipulation
(2013-04-01)
Yu, Tung-Ming
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Yang, Shih-Mo
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Fu, Chien-Yu
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Liu, Ming-Huei
;
Hsu, Long
This paper reports a fabrication technology which integrates organic opto-electrowetting (OEW) with PEGDA-based microfluidics between stacked ITO glass chips for droplets generation and manipulation. Organic OEW can be realized by using titanium oxide phthalocyanine (TiOPc) as a photoconductive layer. Optical images can be projected on an organic OEW area to induce the local virtual electrodes which reduce the surface energy for actuating droplets. Low-molecular-weight (LMW) PEGDA (poly(ethylene) glycol diacrylate) material is used to form stable and biocompatible microchannels between the stacked ITO glass chips by UV photopolymerization process. PEGDA-based microfluidics provides a simpler way to enhance droplets applications in organic OEW. We demonstrate (1) the droplet formation in PEGDA microstructure, (2) the motion of droplet-in-air and droplet-in-oil operated by TiOPc OEW in this platform. This technology requires only spin-coating and UV exposure and is more cost-effective than previous methods. (C) 2011 Elsevier B.V. All rights reserved.
Light-driven manipulation of picobubbles on a titanium oxide phthalocyanine-based optoelectronic chip
(2011-04-11)
Yang, Shih-Mo
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Yu, Tung-Ming
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Huang, Hang-Ping
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Ku, Meng-Yen
;
Tseng, Sheng-Yang
Microbubbles have a variety of applications in science and biological technology. Here, we demonstrate the manipulation of the picoliter gas bubble (picobubble) based on the optoelectronic-mechanism. The organic photoconductive material, titanium oxide phthalocyanine (TiOPc), was developed to make the light-sensitive substrate of this optoelectronic chip. The virtual electrodes are formed by projecting the dynamic light pattern onto TiOPc layer for generating the desired nonuniform electric field. The picobubble suspended in silicone oil can be manipulated with the velocity of 40-50 mu m/s. The driving force up to 160 pico-Newtons could be generated for manipulating a gas bubble of 300 picoliters. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580760]
Measurement of macrophage adhesion by optical tweezers with backward-scattered detection
(2010)
Wei, Sung-Yang
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Su, Yi-Jr
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Shih, Po-Chen
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Yang, Shih-Mo
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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.