• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.139-139
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• 2003

많은 압전 후막은 여러 감지소자, 통신 및 사무자동화 기기, 전기 및 전자부품, 의료장비 및 국방산업에 까지 널리 응용되어 왔다. 그 중에서도 압전특성이 뛰어난 PZT 후막은 마이크로 펌프, 밸브, 헤드, 모터, 트랜스듀서 뿐 아니라 최근 바이오칩용 센서와 액추에이터로서 널리 연구되고 있다. 또한 마이크로 센서와 액추에이터 의 제작 및 구동을 위한 MEMS 기술의 도입으로 실리콘 베이스의 소자 개발이 집중되고 있다. 스크린 프린팅 방법은수 마이크론에서 수십 마이크론 후막의 실현이 용이하고 비교적 경제적이며 소자신뢰도가 높고 대량생산에 유리하여 활발한 연구가 진행 중이다. 그러나 후막은 벌크에 비해 기공률이 높고, 또 소자응용에 있어서 고온소결 시 MEMS공정을 위한 실리콘 베이스 기판과의 확산 및 반응에 의 한 계면 및 활물질 성능의 저하가 문제가 되고 있다. 따라서 본 연구에서는 스크린 프린팅과 더불어 졸 코팅 방법의 도입으로 후막의 성형 및 소결 밀도를 높임과 동시에 여러 확산 방지 막의 증착으로 capacitor 형 PZT 후막의 물성 및 전기 적 특성을 향상시키고자 하였다.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.100-105
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• 2021

This paper proposes the polydimethylsiloxane (PDMS) blade coating method for fabrication of paper-based analytical device (PAD) that is able to monitor the disease diagnosis and progress without special analytical equipment. The mold that has PAD design is easily modified by using laser cutting technique. And the fabricated mold is used for hydrophobic barrier formation by blade coating. We have optimized the stable formation of PDMS hydrophobic barrier as blade coating condition, which is established by analyzing the structure of the PDMS hydrophobic barrier and change of hydrophilic channel size as thickness of the ink and contact time with the chromatography paper. Based on optimal condition, we demonstrate that PAD as biosensor can apply to detect protein, glucose, and metal ion without special analysis equipment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.24-28
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• 2005

A micromachined biochip with a three dimensional silicon chamber was developed for the construction of biosensors. Anisotropic etching was used fur the formation of the chamber on the p-type silicon wafer(100) and then was glued to the Pyrex glass bottom-substrate with pre-deposited platinum electrode. The electrochemical characterization of its Pt electrode and Ag/AgCl reference electrode was investigated.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.553-558
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• 2016

A DC-DC converter for CMOS image sensors in bio-sensor chips is proposed. The DC-DC converter generates a PCP voltage, that is an on voltage of a pixel, and an NCP voltage, that is an off voltage of a pixel. The PCP voltage with a ripple voltage of within 1.33V is obtained from a positive charge pump of VPP (=5V) with a ripple voltage of 45.35 by using a regulator. Also, the NCP voltage with a ripple voltage of 0.05mV is obtained from a negative charge pump of VNN (=-2V) with a ripple voltage of 62.8 by using a regulator.

• KSBB Journal
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• v.22 no.6
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• pp.443-446
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• 2007

A prognostic indicator of coronary heart disease, C-reactive protein, was tried to be determined by a batch-type quartz crystal microbalance immunosensor. The sensor was operated by direct-binding mode and the optimum concentration for the corresponding antibody for immobilization was $50{\mu}g/ml$. The reaction buffer for the system was 0.1 M sodium phosphate (pH 7.0) and system operation was performed in the order of baseline stabilization, analyte addition and measurement, and regeneration of the sensor chip with 10 mM NaOH. When plotted in double-logarithmic scale, the sensor showed a linear detection range of 0.27-106.00 nM for rat C-reactive protein with the limit of detection of 0.53 nM. It also showed a good reusability.

• Electronics and Telecommunications Trends
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• v.26 no.3
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• pp.95-104
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• 2011

셀칩(cells on chips)이란, MEMs/NEMs 응용분야 중 생명공학과 관련된 세포분야로의 응용에 이용되는 대표적인 기술로서 현재 전세계에서 경쟁적으로 연구, 개발되고 있다. 셀칩은 생체내부에서 세포가 성장하는 공간적(spatial), 시간적(temporal) 조건을 정교하게 모사(mimicking)함으로써, 복잡한 생화학적 생체 내(in vivo) 환경을 이해할 수 있는 새로운 기회를 창조하고 있다. 또한 셀칩과 다양한 형태의 분석용 센서와의 결합된 시스템을 통하여, 세포기반 질병진단 시스템의 소형화 및 조기진단 시스템 개발을 위한 바이오멤스 핵심 플랫폼 기술로 인식되고 있다. 즉 DNA, 단백질, 세포 등의 바이오 물질을 마이크로/나노시스템 위에서 검출 및 분석함으로써 극미량의 생체물질을 실시간 고감도 분석이 가능하게 할 것이다. 본 고에서는 셀칩분야의 기술 및 응용에 관해 정리하고 있다.

• KSBB Journal
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• v.23 no.3
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• pp.263-270
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• 2008

A poly-(dimethylsiloxane) (PDMS) surface modified by the successive deposition of the polyelectrolytes, poly-(allylamine hydrochloride) (PAH), poly-(diallyldimethylammoniumchloride) (PDAC), poly-(4-ammonium styrenesulfonic acid) (PSS), and poly-(acrylic acid) (PAA), was presented for the application of selective cell immobilization. It is formed via electrostatic attraction between adjacent layers of opposite charge. The modified PDMS surface was examined using static contact angle measurements and fourier transform infrared (FT-IR) spectrophotometer. The wettability of the PDMS surface could be easily controlled and functionalized to be biocompatible through regulation of layer numbers. The modified PDMS surface provides appropriate environment for adhesion to cells, which is essential technology for cell patterning with high yield and viability in the patterning process. This method is reproducible, convenient, and rapid. It could be applied to the fabrication of biological sensing, patterning, microelectronics devices, screening system, and study of cell-surface interaction.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.470-474
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• 2010

In this study, we presents a simple microfluidic approach for generating uniform Poly(ethylene glycol)(PEG) microfiber. Elongated flow pattern of monomer induced by sheath flow of immiscible oil as continuous phase is generated in Y-shape junction and in situ polymerization by UV exposure. For uniform microfiber, we investigate the optimized flow condition and draw phase diagram as function of Ca and Qd. At the region for stable elongated flow pattern, the microfiber generated in microfluidic chip is very uniform and highly reproducible. Importantly, the thickness of microfibers can be easily controlled by flow rate of continuous and disperse phase. We also demonstrate the feasibility for biological application as encapsulating FITC-BSA in PEG microfiber.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.149-163
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• 2019

Under non-uniform electric field, a directional force along the electric field gradient is applied to matter having permanent or induced dipoles. The transport of particles by the directional force is called dielectrophoresis (DEP). Since the strength and direction of the DEP force depend on parameters, such as permittivity and conductivity of particles and surrounding media, and frequency of the applied AC electric field, particle can be precisely manipulated by controlling the parameters. Moreover, unlike electrophoresis, DEP can be applied to any particles where dipole is effectively induced by electric field. Such a DEP technique has been used in various fields, ranging from microfluidic engineering to biosensor and microchip research. This paper first describes the fundamentals of DEP, and discusses representative microelectrode designs used for DEP study. Then, exemplary applications of DEP, such as separation, capture and self-assembly of particles, are introduced.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1100-1106
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• 2008

In this study, we presented rapid and simple fabrication method of functionalized surface on various substrates as a universal platform for the selective immobilization of cells. The functionalized surface was achieved by using deposition of polyelectrolyte such as poly(allyamine hydrochloride) (PAH), poly(diallyldimethyl ammonium chloride) (PDAC), poly(4-ammonium styrene sulfonic acid) (PSS), poly(acrylic acid) (PAA) and fabrication of poly(ethylene glycol) (PEG) microstructure through micro-molding in capillaries (MIMIC) technique on each glass, poly(methyl methacrylate) (PMMA), polystyrene (PS) and poly(dimethyl siloxane) (PDMS) substrate. The polyelectrolyte multilayer provides adhesion force via strong electrostatic attraction between cell and surface. On the other hand, PEG microstructures also lead to prevent non-specific binding of cells because of physical and biological barrier. The characteristic of each modified surface was examined by using static contact angle measurement. The modified surface onto several substrates provides appropriate environment for cellular adhesion, which is essential technology for cell patterning with high yield and viability in the micropatterning technology. The proposed method is reproducible, convenient and rapid. In addition, the fabrication process is environmentally friendly process due to the no use of harsh solvent. It can be applied to the fabrication of biological sensor, biomolecules patterning, microelectronics devices, screening system, and study of cell-surface interaction.