• KSBB Journal
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• 제18권5호
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• pp.429-433
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• 2003

LAL 측정용 chip을 제작하기 위해서 우선 시료의 부피 감소에 대한 비탁법과 비색법을 비교하였다. 비색법은 낮은 부피에서 높은 감도를 보여 주었으며 시료의 부피와 무관하게 같은 endotoxin의 농도에서는 같은 흡광도를 보인다는 결론을 얻었다. Endotoxin의 농도에 따른 표준곡선을 end point법과 kinetic point법을 비교한 결과 대한약전의 기준에 적합한 kinetic point법이 적합하였다. 이러한 기초 실험결과를 통해 PDMS LOC를 제작하여 LAL 시험을 수행하였다. LOC를 이용하여 더 짧은 시간과 더 작은 시료로 시험이 가능하도록 하였다. 특히 PDMS LOC는 복잡한 channel을 쉽게 만들 수 있을 뿐 아니라 mold를 이용하여 상용화를 위한 대량 생산이 가능하다. 따라서 PDMS를 이용한 LOC의 제작과 실험을 통해 기존의 수작업의 LAL 시험을 LOC를 이용한 다중시료 측정과 자동화의 가능성을 제시하였다.

• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.404-409
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• 2004

We fabricated photo-sensor for fluorescence detection in LOC. LOC is high throughput screening system. Our LOC screens biochemical reaction of protein using the immunoassay, and converts biochemical reaction into electrical signal using LIF(Laser Induced Fluorescence) detection method. Protein is labeled with rhodamine intercalating dye and finger PIN photodiode is used as photo-sensor We measured fluorescence emission of rhodamine dye and analyzed tendency of fluorescence detection, according to photo-sensor size, light intensity, and rhodamine concentration. Detection current was almost linearly proportional to two parameters, intensity and concentration, and was inversely proportional to photo-sensor size. Integrated LOC consists of optical-filter deposited photo-sensor and PDMS microchannel detected 50 (pg/${mu}ell$) rhodamine. For integrated LOC including light source, we used green LED as the light source and measured emitted fluorescence.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.305-308
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• 2006

For controlling micro-flows inside a LOC (lab-on-a-chip) a syringe pump or an electronic device for EOF(electro-osmotic flow) have been used in general. However, these devices are so large and heavy that they are burdensome in the development of a portable micro-TAS (total analysis system). In this study, a new flow control system employing pressure chambers, digital switches and speed controllers was developed. This system could effectively control the micro-scale flows inside a LOC without any mechanical actuators or electronic devices We also checked the feasibility of this new control system by applying it to a LOC of micro-mixer type. Performance tests show that the developed control system has very good performance. Because the flow rate in LOC is controlled easily by throttling the speed controller, the flows in complicate microchannels network can be also controlled precisely.

• 전기학회논문지
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• 제56권8호
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• pp.1424-1429
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• 2007

This paper presents a simple and reliable one-touch type multi-immunosensing lab-on-a-chip (LOC) detecting antibodies as multi-disease markers using electrochemical method suitable for a portable point-of-care system (POCS). The multi-stacked LOC consists of a PDMS space layer for liquids loading, a PDMS valve layer with 50 im in height for the membrane, a PDMS channel layer for the fluid paths, and a glass layer for multi electrodes. For the disposable immunoassay which needs sequential flow control of sample and buffer liquids according to the designed strategies, reliable and easy-controlled on-chip operation mechanisms without any electric power are necessary. The driving forces of sequential liquids transfer are the capillary attraction force and the pneumatic pressure generated by air bladder push. These passive fluid transport mechanisms are suitable for single-use LOC module. Prior to the application of detection of the antibody as a disease marker, the model experiments were performed with anti-DNP antibody and anti-biotin antibody as target analytes. The flow test results demonstrate that we can control the fluid flow easily by using the capillary stop valve and the PDMS check valves. By the model tests, we confirmed that the proposed LOC is easily applicable to the bioanalytic immunosensors using bioelectrocatalysis.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2002년도 창립10주년기념 및 국립독성연구원 의약품동등성평가부서 신설기념 국재학술대회:생물학적 동등성과 의약품 개발 전략을 위한 국제심포지움
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• pp.73-78
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• 2002

Microfluidic lab-on-a-chip (LOC) systems have enabled a new generation ofassay technologies in chemical and biomedical sciences. Caliper's microfluidic LOC systems contain a network of microscopic channels through which fluids and chemical are moved in order to perform experiments. The main advantages of these continuous-flow devices are integration and automation of multiple steps in complex analytical procedures to improve the reproducibility of the results, and eliminated the manual labor, time and pipetting errors involved in analyses. The present talk is devoted to give a brief introduction of microfluidic basics and to present in applying continuous-flow microchips to drug screening with model enzyme assays.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.71.2-71.2
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• 2005

• 대한기계학회논문집B
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• 제34권6호
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• pp.579-586
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• 2010

MEMS 기술의 향상과 함께 $\mu$-TAS(Micro Total Analysis System)가 개발 되어 의료 및 생물학 분야가 급속하게 성장했다. $\mu$-TAS의 한 분야로 Chip 위에서 소량의 sample과 반응물을 가지고 혼합공정과 분석공정이 이루어지는 LOC(Lab on a chip)에 관한 연구는 활발하게 연구되어진다. LOC는 마이크로 펌프 와 마이크로 믹서와 같은 microfluidic 장치들로 구성된다. Microfluidic 시스템의 유동이 층류 유동이므로 유체상태의 반응물들을 효율적으로 혼합하고 공급하는 것이 어렵다. 본 논문은 이송 및 혼합이 동시에 이루어지는 MHD micropump의 설계와 제작에 관해 제시하였다. 최종 개선사양은 상용 CFD 프로그램의 해석결과를 통하여 결정하였다.

• 대한기계학회논문집B
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• 제30권2호
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• pp.110-116
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• 2006

A syringe pump or a device using high electric voltage has been used for controlling flows inside a LOC (lab-on-a-chip). Compared to LOC, however, these microfluidic devices are large and heavy that they are burdensome for a portable ${\mu}-TAS$ (micro total analysis system). In this study, a new flow control technique employing pressure regulators and pressure chambers was developed. This technique utilizes compressed air to control the micro-scale flow inside a LOC, instead of a mechanical actuator or an electric power supply. The pressure regulator controls the output air pressure by adjusting the variable resistor attached. We checked the feasibility of this system by measuring the flow rate inside a capillary tube of $100{\mu}m$ diameter in the Re numbers ranged from 0.5 to 50. In addition, the performance of this flow control system was compared with that of a conventional syringe pump. The developed flow control system was found to show superior performance, compared with the syringe pump. It maintains automatically the: air pressure inside a pressure chamber whether the flow inside the capillary tube is on or off. Since the flow rate is nearly proportional to the resistance, we can control flow in multiple microchannels precisely. However, the syringe pump shows large variation of flow rate when the fluid flow is blocked in the microchannel.

• 연구논문집
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• 통권33호
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• pp.17-25
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• 2003

In this work, thermal design of a PCR chip for LOC is systematically conducted. From the numerical simulation of a PCR chip based on the finite volume method, how to control the average temperature of a PCR chip and the temperature difference between the denaturation zone and the annealing zone is presented. The average temperature is shown to be controlled by adjusting heat input and a cooler as well as a heater is shown to be necessary to obtain three individual temperature zones for polymerase chain reaction. To reduce the time required, a heat sink for the cooler is not included in the calculation domain for the PCR chip and heat sink design is conducted separately by using a compact modeling method, the porous medium approach.

• 기계와재료
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• 제17권1호통권63호
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• pp.26-32
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• 2005