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Undergraduate Student (Fall
2019): Teaching Assistant: Juhwan Park Related Articles:
"Reciprocating flow-assisted
nucleic acid purification using a finger-actuated microfluidic device"
(2020) |
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Undergraduate Student (Summer
2018): Teaching Assistant: Jaejung Son Related Articles:
"Hand-maneuverable collagen sheet with micropatterns
for 3D modular tissue engineering" (2019) |
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Undergraduate Student (Spring
2018): Teaching Assistant: Juhwan Park Related Articles: "Finger-actuated microfluidic concentration gradient generator compatible with a microplate" (2019)
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Sol-Gel Transitional Hydrogel Microarchitectures: We developed a facile method to fabricate free-standing, 3D hydrogel microarchitectures of chemically sol-gel transitional hydrogels, which is based on the use of hydrophilic substrate and aerosol of gelling agent without molding process. Using proposed methods, we fabricated hydrogel microarchitectures of sheets, meshes, or microunits without morphological distortions on the microscale. These microarchitectures can be applied as a biofabrication unit to generate complex composites with controlled microscale structures for a variety of applications such as 3D cell culture systems, tissue morphogenesis study, and modular biofabrication of artificial tissues. Undergraduate Student (Summer
2010): Teaching Assistant: Wonhye Lee Related Articles:
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Optoelectrofluidic Colloidal Assembly: We present a new method, termed optoelectrofluidic colloidal assembly (OCA), for preparing 2D colloidal crystals. In this letter, the first investigation of 2D colloidal assembly due to the electrohydrodynamic mechanisms in an optoelectrofluidic device has been performed. The normalized distance among the assembled particles and the assembly rate according to the applied AC signal have been analyzed. On the basis of this OCA, the control of both the colloidal crystal pattern in a large area and the distance among the assembled particles is simply possible by controlling the projected light pattern and the applied AC signal. Undergraduate Student (Winter
2009): Teaching Assistant: Hyundoo Hwang Related Articles: |
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Microfluidic Pycnometer: A particle situated in a
microfluidic interface with different fluid density moves toward the
lower-density fluid, driven by the asymmetric hydrostatic pressure
acting on the submerged particle. In addition to hydrostatic pressure
differences on the particle, we were concerned not only about fluid
momentum difference caused by solution density and flow rate but also
about rotational motion due to asymmetric buoyancy driven by density
gradient. The experimental results and numerical expectation proved our
theoretical estimation, and here this behavior explains a new principle
termed pyklinophoresis
(Greek; pyk-:density,
-klino-:gradient,
-phoresis:
migration), which enables in situ analysis of microfluidic liquid
samples. An analytical model for pyklinophoresis was provided as a
proof-of-concept and the analytical results of sucrose and volatile
solutions were also demonstrated. Undergraduate Student (Winter
2008 - Summer 2008): Teaching Assistant: Joo H. Kang Related Articles: |
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Micro-Image Projection System: We demonstrates a micro image projection system for optoelectrofluidic manipulation of microparticles using a conventional projector. Optoelectrofluidic manipulators such as an optoelectronic tweezers (OET) is a powerful technology for microparticle manipulation using dielectrophoresis (DEP) induced by projecting and controlling dynamic optical images. In this research, we have developed a micro-image projection system using a conventional image projector for the optoelectronic microparticle manipulation. This simple, low-cost ($1000) projection system provides the performance enhancement of the optoelectronic particle manipulation. The resolution can be varied by exchanging the objective lens and adjusting focal distance. We also compare this system with the conventional lens-integrated lab-on-a-display system and analyze the main factors which cause the difference of particle motions. This new micro-image projection system can be useful for several applications using micro-image projection as well as the optoelectrofluidic microparticle manipulation. Undergraduate Students (Winter
2008 - Spring 2008): Teaching Assistant: Hyundoo Hwang Related Articles: |
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Magnetophoretic Multiplexed Immunoassays: We demonstrates a new
magnetophoretic position detection method for multiplexed immunoassay
using colored microspheres as an encoding tool in a microchannel.
Colored microspheres conjugated with respective capture molecules are
incubated with a mixture of target analytes, followed by reaction with
the probe molecules which had been conjugated with superparamagnetic
nanoparticles (SMNPs). Under the magnetic field gradient, the resulting
microspheres are deflected from their focused streamlines in a
microchannel, and respective colored microspheres are detected using
color charge-coupled device (CCD) in a specific detection region of the
microchannel. The color and position of respective colored microspheres
are automatically decoded and analyzed by MATLAB program, and the
position was correlated with the concentration of corresponding target
analytes. Undergraduate Student (Spring
2007 - Winter 2008): Teaching Assistant: Young Ki Hahn Related Articles: |
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Dielectrophoretic Oocyte Selection: A new separation method of
porcine oocytes for in
vitro fertilization has been described. Conventional
manual selection of oocyte highly depends on the expert's experience
and lacks universal standards for identifying the quality of oocyte. In
this study, an electrode array chip with castellated shape was
developed to evaluate dielectrophoretic (DEP) velocities of oocytes.
Based on different DEP response, the selected group of oocytes that
moved showed a better developmental potential than the group of oocytes
that stayed, representing a higher rate of blastocyte formation and a
lower rate of polyspermic fertilization. This method will open the
possibility to deveop an automatic tool for oocyte selection, which
would be helpful for assisted reproductive technologies such as
transgenic and clonal animal production. Undergraduate Student (Winter
2007 - Spring 2007): Teaching Assistant: Wonjae Choi Related Articles: **(2007. 09. 05) Congratulations! Do-Hyun received a Paper Award supported by 2007 Winter/Spring KAIST URP (undergraduate research participation) program. |
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Microfluidic Optical Manipulator: A
new programmable microfluidic platform, called
lab-on-a-display, for massive parallel manipulation of live
cells and microparticles using dielectrophoresis generated from a
projected image of a liquid crystal display (LCD) has been developed.
However, several interaction forces - among the microparticles and
between target particles and device surface - interfere with the
effective and non-contact particle manipulation. Here we describe
experimental investigation and numerical simulation of
the interactions. Finally, we suggest a new platform called
3-dimensional optoelectronic tweezers (3D OET) to prevent the
particle-surface interactions by vertical focusing of
the particles. In addition to these works, we have also
developed a FLASH-based control program for real-time interactive
manipulation. Undergraduate Students (Winter
2007 - Spring 2007): Teaching Assistant: Hyundoo Hwang Related Articles: |
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Electrochemical Detection: A sensitive and rapid
electrochemical detection of human cardiac troponin I
(cTnI) in the early diagnosis of acute myocardial infarction has been
demonstrated using a microchip fabricated by
assembling a surface- functionalized poly(dimethylsiloxane)(PDMS)
microchannel with an interdigitated array (IDA) gold electrode. The
detection experiments were performed with successive injection of cTnI,
alkaline phosphatase (AP)-labeled anti-cTnI, and p-aminophenylphosphate.
Then, cyclic voltammograms were obtained by the oxidation peak current
proportionally to the concentration of enzymatic product, p-aminophenol. The
optical packing density of anti-cTnI on the surface of the PDMS channel
for the highest electrochemical signal was determined. The proper
orientation and the best packing density of antibody as well as no
electrode fouling contributed to the low detection limit (148 pg/ml) of
cTnI within 8 min. Undergraduate Student (Winter
2006 - Spring 2006): Teaching Assistant: Seong-Sik Jo Related Articles:
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