• Journal of Magnetics
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• 제8권1호
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• pp.24-31
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• 2003

The discoveries of antiferromagnetic coupling in Fe/Cr multilayers by Grunberg, the Giant Magneto Resistance by Fert and Grunberg and a large tunneling magnetoresistance at room temperature by Moodera have triggered enormous research on magnetic thin films and magnetoelectronic devices. Large opportunities are especially opened by the spin dependent tunneling resistance, where a strong dependence of the tunneling current on an external magnetic field can be found. We will briefly address important basic properties of these junctions like thermal, magnetic and dielectric stability and discuss scaling issues down to junction sizes below 0.01 $\mu\textrm{m}$$^2$with respect to single domain behavior, switching properties and edge coupling effects. The second part will give an overview on applications beyond the use of the tunneling elements as storage cells in MRAMs. This concerns mainly field programmable logic circuits, where we demonstrate the clocked operation of a programmed AND gate. The second 'unconventional' feature is the use as sensing elements in DNA or protein biochips, where molecules marked magnetically with commercial beads can be detected via the dipole stray field in a highly sensitive and relatively simple way.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권2호
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• pp.76-85
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• 2004

Biodevices composed of biomolecular layer have been developed in various fields such as medical diagnosis, pharmaceutical screening, electronic device, photonic device, environmental pollution detection device, and etc. The biomolecules such as protein, DNA and pigment, and cells have been used to construct the biodevices such as biomolecular diode, biostorage device, bioelectroluminescence device, protein chip, DNA chip, and cell chip. Substantial interest has focused upon thin film fabrication or the formation of biomaterials mono- or multi-layers on the solid surfaces to construct the biodevices. Based on the development of nanotechnology, nanoscale fabrication technology for biofilm has been emerged and applied to biodevices due to the various advantages such as high density immobilization and orientation control of immoblized biomolecules. This review described the nanoscale fabrication of biomolecular film and its application to bioelectronic devices and biochips.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.411.2-411.2
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• 2014

The design of DNA nanostructures is of fundamental importance, the intrinsic value of DNA as a building-block material lies in its ability to organize other bio-molecules with nanometer-scale spacing. Here, we report the fabrication of DNA scaffolds with nano-pores (<10 nm size) that formed easily without the use of additives (i.e., avidin, biotin, polyamine, or inorganic materials) into large-scale structures by assembling DNA molecules at near room temperature ($30^{\circ}C$) and low pH (~5.5). Protein immobilization results also confirmed that a fibronectin (FN) proteins/large scale DNA scaffolds/aminopropylytriethoxysilane (APS)/SiO2/Si substrate with high sensitivity formed in a well-defined manner. The DNA scaffolds can be applied for use with DNA-based biochips, biophysics, and cell biology.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.783-788
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• 2004

Marker proteins of genetically-modified organisms (GMO) and their antibodies were prepared and characterized as major components of an analytical system. We selected two GMO markers, neomycin phosphotransferase II and 5- enolpyruvylshikimate-3-phosphate synthase, and produced them from E. coli employing genetic recombination technology. After purification, their structural conformation and binding affinities to the respective antibodies were characterized. The results showed that the recombinant proteins were identical with commercially obtained reference proteins. We further used them as immunogens to raise polyclonal antibodies capable of discriminating GMO containing protein from non-GMO. Well-characterized marker proteins and antibodies will be valuable as immunoreagents in constructing analytical systems such as biosensors and biochips to measure quantities of GMO.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.455-461
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• 2006

In this study, we have described a method for the fabrication of a protein chip on silicon substrate using hydrophobic thin film and microfluidic channels, for the simultaneous detection of multiple targets in samples. The use of hydrophobic thin film provides for a physical, chemical, and biological barrier for protein patterning. The microfluidic channels create four protein patterned strips on the silicon surfaces with a high signal-to-noise ratio. The feasibility of the protein chips was determined in order to discriminate between each protein interaction in a mixture sample that included biotin, ovalbumin, hepatitis B antigen, and hepatitis C antigen. In the fabrication of the multiplexed assay system, the utilization of the hydrophobic thin film and the microfluidic networks constitutes a more convenient method for the development of biosensors or biochips. This technique may be applicable to the simultaneous evaluation of multiple protein-protein interactions.

• KSBB Journal
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• 제22권6호
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• pp.433-437
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• 2007

본 연구에서는 나노임프린트 리소그래피를 이용하여 500 nm line, 600 nm pore, $1{\mu}m$ pore, $2.5{\mu}m$ pore의 마이크로 수준에서 나노 수준에 이르는 다양한 크기와 모양의 nanopore 형태 패턴을 제작하였다. Thermal imprint 방식과 달리 상온, 저압에서 임프린팅이 가능하며 사용되는 스탬프의 수명을 늘리고 보다 미세하고 복잡한 형태의 패턴을 제작할 수 있는 UV-assisted imprint 방식을 사용하였다. E-beam lithography로 패턴을 각인한 quartz소재의 스탬프를 사용하였으며 스탬프의 재질이 투명하여 UV 조사시 UV curable resin이 경화될 수 있도록 하였다. 또한 스탬프의 표면을 (heptadecafluoro-1,1,2,2-tetrahydrodecyl) trichlorosilane의 monolayer 층으로 미리 코팅하여 임프린트 후 스탬프와 기판과의 releasing을 쉽게함과 동시에 패턴의 일부가 스탬프에 묻어 나와 전사된 패턴에 defect가 없도록 하였다. 또한, gold를 미리 증착하여 임프린팅함으로써 lift-off 시에 필요한 hi-layer 층이 필요 없게 되어 산소 플라즈마를 이용한 에칭이 더욱 쉽고 lift-off 공정이 생략될 수 있도록 하였다. 나노임프린트 공정에 있어 가장 큰 문제점은 잔여층의 생성이며 이러한 잔여층을 제거하고자 산소 플라즈마 에칭을 하였다. 에칭공정을 통해 gold의 표면이 완전히 드러났으며 산소 플라즈마를 통해 gold의 표면이 친수성으로 바뀌어 추후 단백질 고정화를 더욱 쉽게 하였다. 그리하여 나노임프린트 기술을 이용해 나노크기의 바이오소자 제작을 가능하게 하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.378.2-378.2
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• 2016

Biosensors currently suffer from severe non-specific adsorption of proteins, which causes false positive errors in detection through overestimation of the affinity value. Overcoming this technical issue motivates our research. Polyethylene glycol (PEG) is well known for its ability to reduce the adsorption of biomolecules; hence, it is widely used in various areas of medicine and other biological fields. Likewise, amine functionalized surfaces are widely used for biochemical analysis, drug delivery, medical diagnostics and high throughput screening such as biochips. As a result, many coating techniques have been introduced, one of which is plasma polymerization - a powerful coating method due to its uniformity, homogeneity, mechanical and chemical stability, and excellent adhesion to any substrate. In our previous works, we successfully fabricated plasmapolymerized PEG (PP-PEG) films [1] and amine functionalized films [2] using the plasma enhanced chemical vapor deposition (PECVD) technique. In this research, an amine functionalized PP-PEG film was fabricated by using the plasma co-polymerization technique with PEG 200 and ethylenediamine (EDA) as co-precursors. A biocompatible amine functionalized film was surface characterized by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR). The density of the surface amine functional groups was carried out by quantitative analysis using UV-visible spectroscopy. We found through surface plasmon resonance (SPR) analysis that non-specific protein adsorption was drastically reduced on amine functionalized PP-PEG films. Our functionalized PP-PEG films show considerable potential for biotechnological applications such as biosensors.

• Journal of Veterinary Science
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• 제25권1호
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• pp.18.1-18.27
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• 2024

Mastitis is one of the most widespread infectious diseases that adversely affects the profitability of the dairy industry worldwide. Accurate diagnosis and identification of pathogens early to cull infected animals and minimize the spread of infection in herds is critical for improving treatment effects and dairy farm welfare. The major pathogens causing mastitis and pathogenesis are assessed first. The most recent and advanced strategies for detecting mastitis, including genomics and proteomics approaches, are then evaluated. Finally, the advantages and disadvantages of each technique, potential research directions, and future perspectives are reported. This review provides a theoretical basis to help veterinarians select the most sensitive, specific, and cost-effective approach for detecting bovine mastitis early.

• Korean Chemical Engineering Research
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• 제44권1호
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• pp.65-72
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• 2006

자력을 이용한 분리기술의 장점을 이용하여 여러 가지 불순물들이 섞여 있는 현탁 용액으로부터 자성입자를 이용하여 목적 단백질만을 얻어낼 수 있는 기술의 가능성에 대하여 알아보고자 하였다. 자성입자를 이용하는 경우에는 (1) 자성입자 표면에 리간드 고정화, (2) ligand(리간드)와 목적 물질과의 특이적 결합, (3) 자력을 이용한 자성입자의 분리, (4) 목적 물질의 탈착 그리고 (5) 자성입자의 재사용 순서로 진행되어 여러 단계의 공정을 단순화시킬 수 있다. 이러한 자성입자를 이용한 방법은 효율성, 단순성, 까다롭지 않은 조건, 자동화의 용이성, 비용의 저렴함으로 인해 관심이 증대되고 있다. 본 연구에서는 표면이 카르복실기로 처리된 자성입자에 IgG 항체를 고정화시킨 후 IgG를 목적 단백질로 하여 이를 분리해내고자 하였다. 이를 위하여 자성입자 표면에 다른 물질과의 비특이적 결합이 일어나지 않을 조건에 대하여 확인해 보았으며, IgG 항체를 배향성 고정화시켜 자성입자가 목적 단백질과 보다 효과적으로 결합하여 목적 단백질인 IgG만을 선택적으로 분리해 낼 수 있는지에 대하여 알아보았다. 높은 pH를 사용할 경우 비특이적 흡착을 줄일 수 있었으며, IgG 항체 고정화된 자성입자를 사용할 경우 목적 단백질인 IgG와 선택적으로 반응함을 알 수 있었다. IgG 항체의 고정화에서 Fc지역 C-terminus에 인접해 있는 탄수화물 부분을 이용하여 배향성을 준 경우, IgG 항체 내의 아민기와 고정화시키는 비배향성 고정화 방법보다 항원과의 결합능력이 약 2배 높았다.