• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.107-111
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• 2020

최근 고령화 사회가 진행이 되면서 건강과 진단에 대한 많은 관심이 증대되고 있다. 정확한 진단이 가능한 guided surgery를 위한 다양한 바이오 이미징 시스템 분야가 중요하게 대두되면서 정확한 측정과 실시간 확인 등이 가능한 형광 이미징 시스템이 중요한 분야로 대두되었다. 현재 사용되고 있는 부분은 NIR-I이 주를 이루고 있으나 분해능의 향상 및 깊고 정확하게 형광을 확인하기 위해서 NIR-II 부분의 연구를 많이 진행 중에 있다. 본 논문에서는 NIR-I과 NIR-II의 차이점과 광학적인 특성, 그리고 형광영상 시스템의 SBR(signal to background ration)에 대해서 NIR-II의 미(Mie) 산란을 유한요소(FEM)법을 이용하여 확인을 하였으며 최종적으로 Skin phantom을 제작 및 Fluorescence를 측정을 함으로써 SBR이 NIR-I보다 NIR-II 영역에서 16.2배 더 높은 것을 확인하였다. 형광 이미징 시스템의 SBR 증대는 NIR-I영역대 보다 NIR-II영역이 효과를 이룰 것으로 확인이 되며 이를 통해 guided surgery나 bio-sensor, 또한 형광을 이용한 전자부품의 결함을 확인할 수 있는 디바이스 등의 다양한 응용분야에 활용할 수 있을 것으로 예상한다.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.497-498
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• 2008

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2489-2493
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• 2012

A new fluorescent system (acridine/RTIL hybrid gel) confined in the 3D micro-structure of a poly(lactic acid) membrane were prepared from 1-butyl-3-methylimidazolium-based ionic liquids ([bmim]X (X = $SbF_6$, $NTf_2$, Cl); RTILs), poly(lactic acid) (PLA), and acridine via the sol-gel route. SEM images showed that, in the presence of [bmim]$SbF_6$ and [bmim]$NTf_2$, 3D-ly paticulated structures were created inside the PLA membranes and acridine/RTIL hybrid gels were confined in gabs of particulates. However, the use of [bmim]Cl induced the formation of a 3D-ly porous structure containing the hybrid gel of acridine/[bmimCl in the micropores. The three fluorescent systems exhibited different fluorescence behaviors (fluorescence maximum and intensity) depending on the C2-H acidity scale of the RTILs (or their anion type). Acridine gels hybridized with [bmim]$SbF_6$ and [bmim]$NTf_2$ showed blue fluorescence with relative high intensity, whereas the hybrid gel with [bmim]Cl exhibited almost no fluorescence under dry conditions. However, the acridine/[bmim]Cl hybrid system in the micro-porous PLA membrane started to emit fluorescent light under humid conditions and showed a possible response, indicating that it could be applied as a humidity sensor.

• Journal of Microbiology and Biotechnology
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• 제11권6호
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• pp.979-985
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• 2001

A fluorometric detection technique for HDL (High Density Lipoprotein) and LDL (Low Density Lipoprotein) was developed for application in a fiber-optic immunosensor using a protein A Langmuir-Blodgget (LB) film. For the fluorescence immunoassay, antibodies specific to HDL or LDL were imobilied on the protein A LB film, and a fluorescence amplification method was developed to overcome their weak fluorescence. The deposition of protein A using the LB technique was monitored using a surface pressure-are $({\pi}-A)$ curve, and the antibody immobilization of the protein A LB film was experimentally verified. The immobilized antibody was used to separate only HDL and LDL from a sample, then the fluorescence of he separated HDL or LDL was amplified. The amount of LDL or HDL was measured using the developed fiber optic fluorescence detection system. The optical properties resulting from the reaction of HDL or LDL with o-phtaldialdehyde, detection range, response time, and stability of the immunoassay were all investigated. The respective detection ranges for HDL and LDL were sufficient to diagnose the risk of coronary heart disease. The amplification step increased the sensitivity, while selective separation using the immobilized antibody led to linearity in the sensor signal. The regeneration of the antibody-immobilized substrate could produce a stable and reproducible immunosensor.

• Journal of the Optical Society of Korea
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• 제10권3호
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• pp.130-142
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• 2006

Lab-on-a-chip technology is attracting great interest because the miniaturization of reaction systems offers practical advantages over classical bench-top chemical systems. Rapid mixing of the fluids flowing through a microchannel is very important for various applications of microfluidic systems. In addition, highly sensitive on-chip detection techniques are essential for the in situ monitoring of chemical reactions because the detection volume in a channel is extremely small. Recently, a confocal surface enhanced Raman spectroscopic (SERS) technique, for the highly sensitive biological analysis in a microfluidic sensor, has been developed in our research group. Here, a highly precise quantitative measurement can be obtained if continuous flow and homogeneous mixing condition between analytes and silver nano-colloids are maintained. Recently, we also reported a new analytical method of DNA hybridization involving a PDMS microfluidic sensor using fluorescence energy transfer (FRET). This method overcomes many of the drawbacks of microarray chips, such as long hybridization times and inconvenient immobilization procedures. In this paper, our recent applications of the confocal Raman/fluorescence microscopic technology to a highly sensitive lab-on-a-chip detection will be reviewed.

• 대한기계학회논문집B
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• 제38권10호
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• pp.853-858
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• 2014

본 연구는 미세유동칩을 이용하여 당의 일종인 cyclodextrine(CD)과 알루미늄 이온 검출이 가능한 polydiacetylene(PDA)이 집적된 미세섬유를 제작하는 방법을 제안한다. PDA는 공액 고분자의 일종으로 외부 자극에 대해 blue-to-red 색 전이 및 형광이 발현되며 원료가 되는 PCDA의 head group에 따라 자극에 대한 감도가 달라지는 매력적인 특성을 가지고 있다. 따라서, 이온간 교차결합으로 야기되는 하이드로젤 형성 메커니즘과 미세유동칩 내 3차원 유체집속효과를 활용하여 PCDA-EDEA 기반의 diacetylene(DA) 단량체가 집적된 센서 섬유를 제작하였다. 섬유 내 DA 단량체는 UV에 의해 파란색의 PDA로 상 전이가 일어나며 CD나 알루미늄 이온에 반응하여 붉은색으로의 색 전이 및 붉은 형광이 발현되는 특성을 보였다. 또한 형광세기는 CD와 금속 이온의 농도에 따라 변화하는 특성을 나타내었다. 이는 미세섬유가 건조된 경우에도 동일하게 관찰되었다.

• 대한화학회지
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• 제55권6호
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• pp.932-935
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• 2011

Using tetrabutyl titanate as precursor, $Eu^{3+}$ doped $TiO_2$ nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with $Eu^{3+}$ doped $TiO_2$ was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was quenched by chlorpyrifos and the quenching rate constant ($k_q$) was $1.24{\times}10^{11}\;L/mol{\cdot}s$ according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of $TiO_2$ nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (${\Delta}G_{et}$) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was proportional to chlorpyrifos concentration. The range of detection was $5.0{\times}10^{-10}-2.5{\times}10^{-7}mol/L$ and the election limit ($3{\sigma}$) was $3.2{\times}10^{-11}$ mol/L.

• 분석과학
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• 제11권5호
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• pp.409-412
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• 1998

수용액 중의 europium(III) 이온을 europium(III) 이온의 농도에 따른 calmodulin의 형태변화 때문에 나타나는 형광세기를 측정함으로써 정량하는 방법에 대하여 조사하였다. 광섬유센서는 광섬유의 끝 부분에 투석막을 이용하여 지시용액을 담을 공간을 만들고, 여기에 fluorescein으로 표지된 calmodulin, EGTA 및 완충용액을 넣는 방법으로 제작하였다. 지시용액으로 $5.0{\times}10^{-5}M$ calmodulin, 0.5 mM, EGTA, 5.0 mM Tris-HCl 완충용액을 사용하고, 용액의 pH, 들뜸파장 및 형광 측정파장을 각각 7.0, 495 nm와 520 nm로 고정하였을 때의 europium(III) 이온에 대한 검정곡선을 작성하였다. 검출 한계는 $1.0{\times}10^{-11}M$ 이었고, 직선감응범위는 $1.0{\times}10^{-11}M{\sim}1.0{\times}10^{-9}M$ 이었다. 광섬유센서의 감응 시간은 15분 이었다. Europium(III) 이온을 본 방법으로 정량할 때, $Na^+$ 이온과 $K^+$ 이온은 전혀 방해를 하지 않았으나 $Ca^{2+}$ 이온은 심하게 방해하였다.

• 한국환경과학회지
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• 제29권2호
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• pp.201-207
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• 2020

A new chemosensor based on a self-assembled system has been devised to detect Hg²⁺ions efficiently. We demonstrated that the amphiphilic building blocks consisting of pyrene and boronic acid (1) aggregate in aqueous solutions and provide an outstanding sensing platform for sensitive detection. The self-assembled 1 exhibited high selectivity and sensitivity for Hg²⁺ion detection via fluorescence quenching, where the Hg²⁺ion detection ensued from a fast transmetallation of 1. The Stern-Volmer (SV) quenching constant for its fluorescence quenching by Hg²⁺ions was approximately 1.58 × 10⁸ M^-1. In addition, self-assembled 1 exhibited excellent sensing abilities at nano-molar concentration levels when tap water and freshwater samples were contaminated with of Hg²⁺ ions.

• 센서학회지
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• 제14권5호
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• pp.308-312
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• 2005

We present a microfluidic chip designed for the detection of antibody by using quantum dots fluorescence and a microbead-based assay. A custom designed PDMS microfluidic chip with multi-layer channel is utilized for capturing microbeads; antibody injection into each micro-well; QD injection; and fluorescence detection. The experiment using the fabricated microfluidic chip has been performed on solutions with various concentrations of antibody and has shown correlated fluorescent intensities.