Browsing by Author "Fan, Shih-Kang"

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3D droplet transportations by EWOD actuations on flexible polymer films
(2005)
Yang, Hanping
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Fan, Shih-Kang
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Lin, Chang-Pau
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Wu, Chien-Tai
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Hsu, Wensyang
3-D droplet transportation of ElectroWetting On Dielectric (EWOD) actuation with flexible substrate is proposed. Instead of glass substrate, a polymer film is taken to fabricate the microfluidic device for the droplet demonstrating out of plane motions. Two kinds of tests, tilted test and curved test, are performed, and a model of minimum required actuation voltage is presented, and compared with the results of tilted test. The current model matches experiment data much better than the conventional ones. In the curved test, the droplet successfully transports from bottom to the top.
A highly efficient bead extraction technique with low bead number for digital microfluidic immunoassay
(2016-01)
Huang, Cheng-Yeh
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Tsai, Po-Yen
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Lee, I-Chin
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Hsu, Hsin-Yun
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Huang, Hong-Yuan
Here, we describe a technique to manipulate a low number of beads to achieve high washing efficiency with zero bead loss in the washing process of a digital microfluidic (DMF) immunoassay. Previously, two magnetic bead extraction methods were reported in the DMF platform: (1) single-side electrowetting method and (2) double-side electrowetting method. The first approach could provide high washing efficiency, but it required a large number of beads. The second approach could reduce the required number of beads, but it was inefficient where multiple washes were required. More importantly, bead loss during the washing process was unavoidable in both methods. Here, an improved double-side electrowetting method is proposed for bead extraction by utilizing a series of unequal electrodes. It is shown that, with proper electrode size ratio, only one wash step is required to achieve 98% washing rate without any bead loss at bead number less than 100 in a droplet. It allows using only about 25 magnetic beads in DMF immunoassay to increase the number of captured analytes on each bead effectively. In our human soluble tumor necrosis factor receptor I (sTNF-RI) model immunoassay, the experimental results show that, comparing to our previous results without using the proposed bead extraction technique, the immunoassay with low bead number significantly enhances the fluorescence signal to provide a better limit of detection (3.14 pg/ml) with smaller reagent volumes (200 nl) and shorter analysis time (<1 h). This improved bead extraction technique not only can be used in the DMF immunoassay but also has great potential to be used in any other bead-based DMF systems for different applications. (C) 2016 AIP Publishing LLC.
A Monolithic Lab-on-a-Chip for Electrochemical Detection
(2012)
Chen, Jianfeng
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Yu, Yuhua
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Yang, Sheng
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Fan, Shih-Kang
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Zhou, Jia
This paper reports a novel monolithic lab-on-a-chip (LOC) with an electrochemical system embedded in an electrowetting on dielectric (EWOD) microfluidic device for the first time. The fabrication process is compatible with IC technology. This chip could not only merge and transport droplets successfully, but show good electrochemical responses of glucose and glucose oxidase with the sensitivity of 0.028mA/mM and the statistic adjust R-square of 0.9549.
A new supramolecular film formed from a silsesquioxane derivative for application in proton exchange membranes
(2012-01-14)
Cheng, Chih-Chia
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Yen, Ying-Chieh
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Ko, Fu-Hsiang
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Chu, Chih-Wei
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Fan, Shih-Kang
A new polyhedral oligomeric silsesquioxane ionomer (HO-doped PUSS-C11-Py) has been investigated. This new ionomer is able to self-assemble through macromers by quadruple hydrogen bonding interactions into a physically crosslinked polymer-like material that can be easily fabricated into films with micro-phase separation. This HCl-doped POSS-C11-Py membrane exhibits higher proton conductivity than a typical Nafion membrane at high temperature, which is extremely rare for a non-sulfonic acid system. This newly developed material may provide an alternative route toward design and fabrication of a new type of proton exchange membranes.
AMPFLUID: Aggregation Magnified Post-Assay Fluorescence for Ultrasensitive Immunodetection on Digital Microfluidics
(2015-02-01)
Huang, Cheng-Yeh
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Shih, Po-Huai
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Tsai, Po-Yen
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Lee, I-Chin
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Hsu, Hsin-Yun
Several strategies are currently employed to enhance the detection limit of bead-based assays, but all these approaches improve the sensitivity by varying the assay procedures chemically or biologically. In previous digital microfluidic setups for bead-based immunoassay, the magnetic beads were suspended for detection. We investigated the effect of bead aggregation in such an immunoassay system and propose the aggregation magnified post-assay fluorescence for ultrasensitive immunodetection on digital microfluidics (AMPFLUID). The detection signal and sensitivity are further enhanced even at the post-assay stage without altering the original assay protocol on employing magnetically triggered post-assay aggregation of beads in a digital microfluidic setup followed by processing of the fluorescent signal. This method is shown to enhance the fluorescent signal with increased consistency and sensitivity after appropriate charge-coupled device (CCD) calibration. This method of on-chip detection allows the fulfilment of consumption of a volume at the nanoliter level and a limit of detection in the range picogram/mL. In our sTNF-RI model immunoassay, only 2.5 nL of sample is required; a detection limit 15 pg/mL is achieved. The decreased uncertainty of the measure is indicated by the error bars and coefficient of variation.
AN AFFINITY SENSOR IMPROVED BY EWOD ACTUATOR-BASED MICROFLUIDIC CHIP
(2009-12-01)
Liu, Chin-Wei
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Lin, Chi-Chang
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Chen, Li-Chia
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Fan, Shih-Kang
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Chang, Hsien-Chang
We propose an improved immunoassay method with EWOD-based microfluidic biochip. Electro-wetting on dielectric (EWOD) is based on contact angle-changed phenomenon of droplet on the channel surface. The reactant-containing droplet can be moved from reservoir to a modified electrode area, which a stir function can be provided by controlling AC electro-osmosis flow (ACEOF). The immunochemistry reaction takes place on our modified area via electro-wetting actuation, and the signal from fluorescent or electrochemical impedance spectroscopy (EIS) was used to confirm the performance of designed element.
Asymmetric electrowetting - moving droplets by a square wave
(2007)
Fan, Shih-Kang
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Yang, Hanping
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Wang, Tsu-Te
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Hsu, Wensyang
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機械工程學系
Here droplet oscillation and continuous pumping are demonstrated by asymmetric electrowetting on an open surface with embedded electrodes powered by a square wave electrical signal without control circuits. The polarity effect of electrowetting on an SU-8 and Teflon coated electrode is investigated, and it is found that the theta-V ( contact angle-applied voltage) curve is asymmetric along the V = 0 axis by sessile drop and coplanar electrode experiments. A systematic deviation of measured contact angles from the theoretical ones is observed when the electrode beneath the droplet is negatively biased. In the sessile drop experiment, up to a 10 degrees increment of contact angle is measured on a negatively biased electrode. In addition, a coplanar electrode experiment is designed to examine the contact angles at the same applied potential but opposite polarities on two sides of one droplet at the same time. The design of the coplanar electrodes is then expanded to oscillate and transport droplets on square-wave-powered symmetric ( square) and asymmetric ( polygon) electrodes to demonstrate manipulation capability on an open surface. The frequency of oscillation and the speed of transportation are determined by the frequency of the applied square wave and the pitch of the electrodes. Droplets with different volumes are tested by square waves of varied frequencies and amplitudes. The 1.0 mu l droplet is successfully transported on a device with a loop of 24 electrodes continuously at a speed up to 23.6 mm s(-1) when a 9 Hz square wave is applied.
Atmospheric-pressure microplasma in dielectrophoresis-driven bubbles for optical emission spectroscopy
(2012)
Fan, Shih-Kang
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Shen, Yan-Ting
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Tsai, Ling-Pin
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Hsu, Cheng-Che
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Ko, Fu-Hsiang
"The manipulation of bubbles and the ignition of microplasma within a 200 nL bubble at atmospheric pressure and in an inert silicone oil environment were achieved. Driven by dielectrophoresis (DEP), bubble generation, transportation, mixing, splitting, and expelling were demonstrated. This process facilitated the preparation of various bubbles with tuneable gas compositions. Different gas bubbles, including air, argon (Ar), helium (He), and Ar/He mixtures, were manipulated and ignited to the plasma state by dielectric barrier discharge (DBD) within a 50 mm-high gap between parallel plates. Moving and splitting the atmospheric-pressure microplasma in different gas bubbles were achieved by DEP. The excited light of the microplasma was recorded by an optical spectrometer for the optical emission spectroscopy (OES) analyses. The characteristic peaks of air, Ar, and He were observed in the DEP-driven microplasma. With the capability to manipulate bubbles and microplasma, this platform could be used for gas analyses in the future."
Characterization and Packaging of Electronic Paper Display Based on Particle Polarization
(2009)
Chiu, Cheng-Pu
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Hsu, Ching-Hsiang
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Chen, Shih-Chiang
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Fan, Shih-Kang
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Chiang, Mei-Tsao
A particle-based reflective electronic paper has been characterized. Based on the particle polarization, we drive the neutral microspheres to form particle chains in a water solution by applying an AC electric field. The particle-chain transformation regulates the incident light and the reflectivity of the display. Here we developed the device packaging with hydrophilic surface treatments and UV sealing techniques. With a passive-matrix addressing scheme, a reflective electronic paper having 64x64 pixels by particle polarization is realized on a 4 inch by 4 inch panel.
Constructing 3D heterogeneous hydrogels from electrically manipulated prepolymer droplets and crosslinked microgels
(2016-10-01)
Chiang, Min-Yu
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Hsu, Yao-Wen
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Hsieh, Hsin-Yi
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Chen, San-Yuan
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Fan, Shih-Kang
Formation of multifunctional, heterogeneous, and encoded hydrogel building blocks, or microgels, by cross-linking and assembly of microgels are two essential steps in establishing hierarchical, complicated, and three-dimensional (3D) hydrogel architectures that recapitulate natural and biological structures or originate new materials by design. However, for the variety of the hydrogel materials crosslinked differently and for the varied scales of microgels and architectures, the formation and assembly processes are usually performed separately, which increases the manufacturing complexity of designed hydrogel materials. We show the construction of hydrogel architectures through programmable formation and assembly on an electromicrofluidic platform, adopting two reciprocal electric manipulations (electrowetting and dielectrophoresis) to manipulate varied objects (i) in multiple phases, including prepolymer liquid droplets and crosslinked microgels, (ii) on a wide range of scales from micrometer functional particles or cells to millimeter-assembled hydrogel architectures, and (iii) with diverse properties, such as conductive and dielectric droplets that are photocrosslinkable, chemically crosslinkable, or thermally crosslinkable. Prepolymer droplets, particles, and dissolved molecules are electrically addressable to adjust the properties of the microgel building blocks in liquid phase that subsequently undergo crosslinking and assembly in a flexible sequence to accomplish heterogeneous and seamless hydrogel architectures. We expect the electromicrofluidic platform to become a general technique to obtain 3D complex architectures.
Cross-scale electric manipulations of cells and droplets by frequency-modulated dielectrophoresis and electrowetting
(2008-08-01)
Fan, Shih-Kang
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Huang, Po-Wen
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Wang, Tsu-Te
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Peng, Yu-Hao
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材料科學與工程學系奈米科技碩博班
Two important electric forces, dielectrophoresis (DEP) and electrowetting-on-dielectric (EWOD), are demonstrated by dielectric-coated electrodes on a single chip to manipulate objects on different scales, which results in a dielectrophoretic concentrator in an EWOD-actuated droplet. By applying appropriate electric signals with different frequencies on identical electrodes, EWOD and DEP can be selectively generated on the proposed chip. At low frequencies, the applied voltage is consumed mostly in the dielectric layer and causes EWOD to pump liquid droplets on the millimetre scale. However, high frequency signals establish electric fields in the liquid and generate DEP forces to actuate cells or particles on the micrometre scale inside the droplet. For better performance of EWOD and DEP, square and strip electrodes are designed, respectively. Mammalian cells (Neuro-2a) and polystyrene beads are successfully actuated by a 2 MHz signal in a droplet by positive DEP and negative DEP, respectively. Droplet splitting is achieved by EWOD with a 1 kHz signal after moving cells or beads to one side of the droplet. Cell concentration, measured by a cell count chamber before and after experiments, increases 1.6 times from 8.6 x 10(5) cells ml(-1) to 1.4 x 10(6) cells ml(-1) with a single cycle of positive DEP attraction. By comparing the cutoff frequency of the voltage drop in the dielectric layer and the cross-over frequency of Re(f(CM)) of the suspended particles, we can estimate the frequency-modulated behaviors between EWOD, positive DEP, and negative DER A proposed weighted Re(f(CM)) facilitates analysis of the DEP phenomenon on dielectric-coated electrodes.
Dielectrophoresis-based microfluidic system
(2011-03-10)
Fan, Shih-Kang
A dielectrophoresis-based microfluidic system includes a first electrode plate, a second electrode plate and a spacing structure. The first electrode plate comprises a first substrate and an electrode layer disposed on one side surface of the first substrate. The second electrode plate comprises a second substrate and a plurality of electrodes. The electrodes are disposed on one side surface of the second substrate which is opposite to the electrode layer, and arranged in a microchannel pattern. The spacing structure is disposed between the first electrode plate and the second electrode plate so that a space is defined between the first electrode plate and the second electrode plate. Accordingly, users can inject microfluid into the space and apply voltage to different electrodes to drive the microfluid to flow towards different directions.
Dielectrophoretic cell concentrator on EWOD-Based chips
(2006)
Huang, Po-Weng
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Wang, Tsu-Te
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Lin, Sheou-Wei
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Chang, Yu-Chi
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Fan, Shih-Kang
Dielectrophoretic concentrators were successfully developed on a EWOD-based chip. In such a chip, two major electrokinetic forces were exerted on objects on different scales. EWOD is used to pump droplets on a mm scale, while DEP manipulates bio-particles on a pm scale. Both cells and polystyrene beads were used to demonstrate the concentration abilities by pDEP and nDEP forces, respectively. Since electrodes are covered with a dielectric layer, instead of creating nonuniform electric fields in the liquid, low frequency signals are consumed in the dielectric layer and providing EWOD. It is necessary to use high frequency signals to generate DEP on a EWOD-based chip. Concentration efficiency, measured by cell count chamber before and after experiments, is around 1.62 with single cycle of pDEP attraction.
Digital Microfluidic Dynamic Culture of Mammalian Embryos on an Electrowetting on Dielectric (EWOD) Chip
(2015-05-01)
Huang, Hong-Yuan
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Shen, Hsien-Hua
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Tien, Chang-Hung
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Li, Chin-Jung
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Fan, Shih-Kang
Current human fertilization in vitro (IVF) bypasses the female oviduct and manually inseminates, fertilizes and cultivates embryos in a static microdrop containing appropriate chemical compounds. A microfluidic microchannel system for IVF is considered to provide an improved in-vivo-mimicking environment to enhance the development in a culture system for an embryo before implantation. We demonstrate a novel digitalized microfluidic device powered with electrowetting on a dielectric (EWOD) to culture an embryo in vitro in a single droplet in a microfluidic environment to mimic the environment in vivo for development of the embryo and to culture the embryos with good development and live births. Our results show that the dynamic culture powered with EWOD can manipulate a single droplet containing one mouse embryo and culture to the blastocyst stage. The rate of embryo cleavage to a hatching blastocyst with a dynamic culture is significantly greater than that with a traditional static culture (p<0.05). The EWOD chip enhances the culture of mouse embryos in a dynamic environment. To test the reproductive outcome of the embryos collected from an EWOD chip as a culture system, we transferred embryos to pseudo-pregnant female mice and produced live births. These results demonstrate that an EWOD-based microfluidic device is capable of culturing mammalian embryos in a microfluidic biological manner, presaging future clinical application.
DISPLAY
(2009-05-28)
Fan, Shih-Kang
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Chiu, Cheng-Pu
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Mo, Chi-Neng
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Chiang, Mei-Tsao
A display including a first substrate, a first electrode, a second substrate, a second electrode, and a mixed solution is provided. The first electrode is disposed on the first substrate, and the second electrode is disposed on the second substrate. In addition, the mixed solution is disposed between the first electrode and the second electrode. Moreover, the mixed solution includes a solution and a plurality of first neutral micro-particles disposed in the solution.
DISPLAY
(2010-06-17)
Fan, Shih-Kang
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Chiu, Cheng-Pu
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Hsu, Ching-Hsiang
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Mo, Chi-Neng
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Chiang, Mei-Tsao
A display includes a first substrate, a first electrode, a second substrate, a second electrode and a display material layer. The first electrode is disposed on the first substrate and the second electrode is disposed on the second substrate. The display material layer is disposed between the first electrode and the second electrode. The display material layer of the invented display includes a solution and a plurality of first micro beads, wherein each of the first micro beads further has a plurality of different axis lengths in different axis directions, and the axis length in at least an axis direction is different from the axis lengths in the rest axis directions so that the first micro beads present different arrangement densities in different driving frequencies under the influence of polarized self-arrangement effect.
DISPLAY MEDIUM AND DISPLAY
(2010-04-01)
Fan, Shih-Kang
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Chiu, Cheng-Pu
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Hsu, Ching-Hsiang
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Chiang, Mei-Tsao
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Mo, Chi-Neng
A display medium and a display are provided. The display medium includes a thermal-sensitive solution and a number of micro particles. The micro particles are dispersed in the thermal-sensitive solution. At a first temperature, the thermal-sensitive solution is in a liquid form, such that the micro particles move freely. At a second temperature, the thermal-sensitive solution is in a colloid form, such that the micro particles are fixed. The first temperature differs from the second temperature.
Droplet manipulation by electrowetting on polymer dispersed liquid crystal
(2007)
Chiu, Cheng-Pu
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Lin, Shang-Chih
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Fan, Shih-Kang
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材料科學與工程學系奈米科技碩博班
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Graduate Program of Nanotechnology , Department of Materials Science and Engineering
Droplets were successfully manipulated on an electrowetting-on-dielectric (EWOD) device whose dielectric layer was a polymer dispersed liquid crystal (PDLC) thin film. Dielectric layer is essential to EWOD since it would store charges and change the surface wettability. Therefore, most of the research on the dielectric material was focused on its dielectric constant and strength. However, besides serving as only a capacitor, many dielectric materials possess other physical or chemical characteristics including optical, thermal, and mechanical properties. In this paper, we introduced and investigated electrowetting on an electro-optic material PDLC. By applying a voltage across the PDLC film, dual phenomena, EWOD and electro-optic effects, were achieved. The proposed droplet manipulating device would be beneficial when light regulation is necessary.
Droplet microfluidic transporting module
(2009-10-08)
Hsu, Wen-Syang
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Young, Han-Ping
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Fan, Shih-Kang
A droplet microfluidic transporting module adapted for transporting a droplet is disclosed to include one or a number of connectors and one or a number of microfluidic transporting platform. Each connector defines a passage extending in one or multiple predetermined directions, and a first driving electrode extending along one side of the passage for the contact of the droplet to be transported. The microfluidic transporting platform is detachably electrically connected with the connector, defining a channel in communication with the passage of the connector and having a second driving electrode extending along one side of the channel for the contact of the droplet to be transported.
Droplet routing in high-level synthesis of configurable digital microfluidic biochips based on microelectrode dot array architecture
(2011-12-01)
Chen, Zhongkai
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Teng, Daniel Hsiang-Yung
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Wang, Gary Chung-Jhih
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Fan, Shih-Kang
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材料科學與工程學系
Droplet-based digital microfluidic lab-on-chips exploiting electrowetting-on-dielectric (EWOD) have been studied over the last decade. With the recent introduction of new highly scalable, reconfigurable and field-programmable microelectrode dot array (MEDA) architecture, there is a compelling need for a new digital microfluidics synthesizer for the new MEDA architecture. Droplet routing is a critical part of the digital microfluidics synthesizer. This paper presents a routing algorithm and the associated performance analysis results. The algorithm is able to route different sizes of reagent and sample droplets simultaneously and also incorporates other characteristics such as diagonal movements and channel-based movements that are specific to the MEDA architecture.