• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.447-452
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• 2013

Microfluidic devices can offer precise control for a verity of tasks involving biological specimen. In this paper, we propose an integrated system consisting of a microfluidic device along with a digital holographic microscope and present three-dimensional (3D) sensing and segmentation of biological microorganisms. When the individual microorganisms are inputted into the microfluidic channel, the holographic microscope records their holograms. The holograms are computationally reconstructed in 3D using Fresnel transform and the reconstructed phase images are used to search the position of microorganisms. Optical experiments are carried out and experimental results are presented to illustrate the usefulness of the proposed system.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1917-1919
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• 2003

본 연구에서는 바이오 및 환경 분야에 적용 가능한 미세 유체소자 제작에 있어서 4" 유리 / 유리 웨이퍼접합을 시도하였으며, 접합결과 90%이상의 접합면적을 보였다. 접합된 샘플을 산 및 알카리 조건에 따른 인장시험결과 모든 조건에서 약 $2kgf/mm^2$ 이상의 접합강도를 보였으며 파괴는 접합면이 아닌 모재에서 발생되었다. 또한 미세유체소자 제작에 있어서 초음파를 이용하여 유리를 가공하였으며, 폭 $300{\mu}m$, 깊이 $200{\mu}m$의 미세채널을 제작하였다.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.754-760
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• 2004

The miniaturization and integration are trend of modern blood analyses. Micro-Bio-Fluidics plays an important role in a micro blood analysis system. In this paper, analysis and design technology for blood analysis system is presented. Numerical simulations of a blood flow in micro separator and reservoir are conducted. As a result, we suggest on-chip micro separator, which performed plasma separation from whole blood in micro channels.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.69-71
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• 2001

본 논문에서는 FACS(fluorescence activated cell sorting)의 초소형화를 위한 미세 유체소자들을 플라스틱 기판에 집적하여 제작하고 전기삼투를 이용해서 세포가 일렬로 이송되는 특성을 시험한다. 제작된 미세 유체 소자는 유리 하부 기판과 플라스틱 상부 기판 및 전원장치로 구성된다. 상부기판은 세포를 주입하기 위한 샘플 측 레저버와 세포를 운반 및 일렬 이송이 가능하게 하는 버퍼를 저장할 두 개의 레저버가 있고 이들이 배출되는 레저버로 구성된다. 마이크로머시닝 기술을 이용하여 실리콘 기판 위에 미세 채널 몰드를 제작한 후 PDMS(polydimethylsiloxane)로 주물을 제작한다. $O_2$ 플라즈마를 이용하여 유리 기판과 PDMS 주물을 접합하며 제작된 채널에 적색 잉크와 bead를 샘플 측에 충전하고 버퍼 측에 sodium borate를 충전한 후 전기삼투로 구동시킨다. bead가 일렬로 이송되도록 전장을 조절하고 이때의 유속과 유량을 측정한다. 다양한 전장에 따른 실험을 통하여 채널의 구조를 최적화한다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.53 no.3
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• pp.57-63
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• 2011

• Journal of the KSME
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• v.54 no.9
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• pp.28-30
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• 2014

이 글은 기존 종양세포 배양법과 항암제 내성 기전 연구에서의 문제점을 극복하기 위한 새로운 방법으로서 microfluidic device를 사용하려는 시도에 관한 것이다.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.738-742
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• 2012

Here, we develop a new nanofilter device for the rapid and efficient separation of nanoparticles and biomolecules, exploiting the use of AAO mebrane with ordered nanopores in the range from 20 nm to 200 nm. Briefly, the chip comprises of a series of the upper and lower PDMS channels containing embedded inlet and outlet ports, and $50{\mu}m$ width microfluidic channel, and AAO membrane to be made the filtering zone. After assembling these components, the acrylate plastic plates were used to fix the device on the top and bottom side. When introducing the samples into the inlet ports of the upper PDMS channel, we were able to separate and concentrate the nanoparticles and target molecules at the filtering zone, and to elute the solutions containing the unwanted materials toward the lower PDMS channels normal to the direction of AAO membrane. To demonstrate the usefulness of the device we apply it to the SERS detection of nucleic acid sequences associated with Dengue virus serotype 2. We report a limit of detection for Dengue sequences of 300 nM and show excellent enhancement of Raman signals from the filter zone of the nanofilter device.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.178-185
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• 2009

Simple and highly efficient droplet merging method is proposed, which enables two nanoliter or picoliter droplets to merge regularly in a straight microchannel. Using a cross channel with inflows of one oil phase through the main channel and two water phases through the side channels, two droplets of different sizes can be generated alternatingly in accordance with flow rate difference of the water phases. It is shown that for a fixed oil phase flow rate, the flow rate of one water phase required for alternating droplet generation increases linearly with the flow rate of another water phase. By this method, the droplets are merged with 100 % efficiency without any additional driving forces.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.139-140
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.361-362
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• 2009