Browsing by Author "Tseng, Sheng-Yang"

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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.
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
;
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.
Controlling the transverse momentum distribution of a light field via azimuth division of a hologram in holographic optical tweezers
(2011-12-01)
Tseng, Sheng-Yang
;
Hsu, Long
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電子物理學系
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Department of Electrophysics
This study proposes a method for creating a light field with controlled distribution of transverse momentum (TM) by displaying a hologram only in an azimuth region that centers at theta(0) and has a range of Delta theta of a spatial light modulator in holographic optical tweezers. This study utilized ray optics to analyze the TM of the resultant field, revealing that the direction of the TM is determined by the center angle of the azimuth region and that the magnitude of the TM is proportional to sind(Delta theta/2), without regarding the intensity. The relationship was verified experimentally. In addition, this study demonstrated moving particles along a designed path and depleting particles by the fields. (C) 2011 Optical Society of America
Effects on Organic Photovoltaics Using Femtosecond-Laser-Treated Indium Tin Oxides
(2016-09-28)
Chen, Mei-Hsin
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Tseng, Ya-Hsin
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Chao, Yi-Ping
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Tseng, Sheng-Yang
;
Lin, Zong-Rong
The effects of, femtosecond-laser-induced periodic surface structures (LIPSS) on an indium tin oxide (ITO) surface applied to an organic photovoltaic (OPV), system were investigated. The modifications of ITO induced by LIPPS in OPV devices result in more than 14% increase in power conversion efficiency (PCE) and short-circuit current density relative to-those of the standard device. The basic mechanisms for the enhanced short-circuit current density are attributed to better light harvesting, increased scattering effects, and more efficient charge collection between the ITO and photoactive layers: Results show that-higher PCEs would be achieved by laser-pulse-treated electrodes.
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.
Fast trapping force calculation by utilizing graphic processing unit
(2012)
Tseng, Sheng-Yang
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Chang, Ai-Tang
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Luo, Chih-Wei
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Hsu, Long
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Kobayashi, Takayoshi
Fast calculation of trapping force provides a more direct way for optimizing designs of optical systems which generate optical traps. In this study, a graphic processing unit (GPU), NVIDIA GTX 275, is used to boost the speed of trapping efficiency calculation under ray optics approximation. The codes of trapping efficiency calculation are implemented in C++. The computing power of GPU is utilized through compute unified architecture device (CUDA) toolkit 4.0. The computing speed is compared with that of central processing unit (CPU), Intel Core 2 Quad Q9550. Over 100x speedup is achieved when single-precision floating-point numbers were used in the calculation.
In-situ Formation and Assembly of Gold Nanoparticles by Gum Arabic as Efficient Photothermal Agent for Killing Cancer Cells
(2013-10-01)
Liu, Ching-Ping
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Lin, Fong-Sian
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Chien, Chih-Te
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Tseng, Sheng-Yang
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Luo, Chih-Wei
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
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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]
Optical guiding with cylindrical mirror system
(2010)
Chang, Ai-Tang
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Tseng, Sheng-Yang
;
Hsu, Long
;
電子物理學系
;
Department of Electrophysics
We proposed a method to guide micro-particles within a millimeter region. A cylindrical mirror is used to create an optical line segment for guiding particles. In order to increase the numerical aperture, Polydimethylsiloxane (PDMS) is poured on the cylindrical mirror. At the top of the PDMS layer, a fluidic channel is fabricated. As a collimated laser beam is incident on the cylindrical mirror, the laser beam is tightly focused and is transformed into a line-shaped pattern in the fluidic channel. In this way, a simple and cost-effective optical guiding system can be achieved.
ORGANIC PHOTOCONDUCTIVE DIELECTROPHORESIS BY USING TITANIUM OXIDE PHTHALOCYANINE FOR MICRO-PARTICLES MANUPULATION
(2010)
Yu, Tung-Ming
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Yang, Shi-Mo
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Huang, Hang-Ping
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Ku, Meng-Yen
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Tseng, Sheng-Yang
This paper reports our updating development for the organic photoconductive dielectrophoresis (OPDEP) by using titanium oxide phthalocyanine (TiOPc) material for the manipulation of micro-objects. The advantages of organic photoconductive material include non-toxicity, low cost, easy coating fabrication, flexibility, panchromaticity and high photosensitivity [1]. TiOPc has the high photoconductivity and the optical absorptions in the near infrared region (550 - 850 nm) to be a candidate of the light-sensitive charge generation layer. OPDEP chip is easily mass-produced by using a spin-coating process. Here, we demonstrate two kinds of the manipulations of micro-particles on our OPDEP chip. Firstly, the trapping and movement of single micro-particle is achieved by the ring shaped virtual electrode. Secondly, the steel rim shaped virtual electrode is designed to rotate micro-particles and characterize the OPDEP induced force.
Synthesis and characterization of a highly two-photon active dendrimer derived from 2,3,8-trifunctionalized indenoquinoxaline units
(2014)
Lin, Tzu-Chau
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Liu, Che-Yu
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Li, May-Hui
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Liu, Yi-You
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Tseng, Sheng-Yang
A dendritic chromophore derived from 2,3,8-trifunctionalized indenoquinoxaline units was synthesized and experimentally shown to manifest very strong and widely-dispersed two-photon absorption (2PA) across the dynamic tuning range of a Ti:sapphire laser. The maximum 2PA of the studied chromophore was found to reach approximate to 31 700 GM, indicating that 2,3,8-trifuctionalized indenoquinoxaline units are useful building moieties for the construction of highly active 2PA-dyes. In addition, this dendritic structure was also demonstrated to effectively regulate the optical power of femtosecond laser pulses at 800 nm.
Synthesis and Characterization of Two-Photon Chromophores Based on a Tetrasubstituted Tetraethynylethylene Scaffold
(2014-06-01)
Lin, Tzu-Chau
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Liu, Yi-You
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Li, May-Hui
;
Liu, Che-Yu
;
Tseng, Sheng-Yang
A new series of model dye molecules composed of three multibranched analogues based on the tetrasubstituted tetraethynylethylene structural motif have been synthesized and experimentally shown to possess strong and widely dispersed two-photon absorption (2PA) in the near-IR region. It was found that the spectral position of the major 2PA band could be tuned by the electronic nature of the selected substitution units. The studied model fluorophores also exhibited fairly low photodegradation of their fluorescence intensity even under prolonged UV-light irradiation, which is beneficial for the development of fluorescence probes that are needed for long-term light exposure. Furthermore, representative chromophores were selected to demonstrate the power-control properties within the femtosecond and nanosecond time domains.