• 전기학회논문지
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• 제58권1호
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• pp.147-154
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• 2009

This paper presents a grating~integrated SPR (Surface Plasmon Resonance) sensor chip for simple and inexpensive biomolecule detection. The grating-integrated SPR sensor chip has two sensing channels having a nano grating for SPR coupling. An external mirror is used for multi channel SPR sensing. The present sensor chip replaces bulky and expensive optical components, such as fiber-optic switches or special shaped prisms, resulting in a simple and inexpensive wavelength modulated multi-channel SPR sensing system. We fabricate a SPR sensor chip integrated with 835 nm-pitch gratings by a micromolding technique to reduce the fabrication cost. In the experimental characterization, the refractive index sensitivity of each sensing channel is measured as $321.8{\pm}8.1nm$/RI and $514.3{\pm}8.lnm$/RI, respectively. 0.5uM of the target biomolecule (streptavidin) was detected by a $1.13{\pm}0.16nm$ shift of the SPR dip in the 10%-biotinylated sample channel, while the SPR dip in the reference channel for environmental perturbation monitoring remained at the same position. From the experimental results, multi-channel biomolecule detection capability of the present grating-integrated SPR sensor chip has been verified. On the basis of the preliminary experiments, we successfully measured the binding reaction rate for the $2\;nM{\sim}200\;nM$ monoclonal-antibiotin, thus verifying biomolecule concentration detectability of the present SPR sensor chip. The binding reaction rates measured from the present SPR sensor chip agredd well with those from a commercialized SPR sensor.

• 센서학회지
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• 제25권2호
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• pp.143-147
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• 2016

Characteristics of the conventional gold (Au) surface plasmon resonance (SPR) chip, bi-metallic(Au/silver (Ag)) SPR chip, and tri-metallic(Au/Ag/Au) SPR chip were investigated and compared in the intensity measurement mode for the enhancement of SPR image sensor reactivity. Reflectance curves of the Au, bi- and tri-metallic SPR chips were acquired in phosphate-buffered saline (PBS) solution and were compared. The line width of the reflectance curve of the bi-metallic chip was the narrowest among the three different types of the chips. Also, the tangential slope of the bi-metallic chip was steeper than those of the other chips. Various concentrations of bovine serum albumin (BSA) were utilized in the SPR experiment. As a result, among the above three chips reflectance variation value of the bi-metallic chip was the largest.

• 산업식품공학
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• 제14권1호
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• pp.49-53
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• 2010

표면 플라즈몬 공명을 이용한 센서는 굴절계 기기의 일종으로서 높은 감도를 가질 뿐만 아니라 비표지 방식이라는 장점을 가지고 있다. 본 연구에서는 재래식 SPR 칩을 이용하여 시판 술 4종의 알코올 함량을 측정하였다. 또한, 재래식 SPR 칩의 감도를 개선하기 위하여 금 박막 위에 금으로 나노형상을 구축하여 나노형상 SPR 칩을 제조하여 모형 술에 대한 감도 개선 효과를 분석하였다. 재래식 SPR 칩을 이용하여 시판 술의 알코올 함량을 측정하기 위한 검량선을 개발하였을 때 시료를 전처리 하지 않고 그대로 측정하였을 때 가장 좋은 검량선을 얻을 수 있었다. 소주, 청주, 이과두주, 탁주 등 시판 술 4종에 대한 1차 회귀식의 검량식에서 결정계수는 각각 0.992, 0.933, 0.918, 그리고 0.984로 나타났다. 한편, 재래식 SPR 칩의 감도를 개선하기 위해 나노형상 SPR 칩을 제조하기 위하여 Langmuir-Blodgett(LB) 방법을 활용하였다. 본 연구에서는 수십 nm 두께의 금 박막을 바닥층으로 하여 그 위에 나노 크기의 실리카 입자를 단분자 층으로 덮어 형틀을 제조하고 다시 그 위에 금을 증착한 후 실리카 입자를 제거하는 방법으로 나노형상을 갖는 SPR 칩을 제조하였다. 나노형상 SPR 칩의 성능을 평가하였을 때 20% 알코올 함량을 가지는 모형 술에 대해서 바닥층의 두께가 50 nm, 나노형상에서 골의 깊이가 20 nm, 나노형상의 배열주기가 300 nm일 때 SPR의 감도가 가장 좋아서 95%의 감도 향상을 얻을 수 있었다. SPR의 감도는 칩과 관련된 인자, 시료의 종류 및 상태에 따라 다르게 나타날 수 있으므로 측정 목적에 알맞은 칩의 설계와 선택이 요구된다.

• 센서학회지
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• 제25권4호
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• pp.243-246
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• 2016

The characteristics of a bimetallic surface plasmon resonance (SPR) chip were investigated to detect a tumor biomarker, carcinoembryonic antigen (CEA). The linewidth and the tangential slope of the reflectance curve of the bimetallic SPR chip was compared with those of the reflectance curve of a conventional gold (Au) SPR chip. The changes in reflectance in response to the variation in CEA in the critical concentration range were analyzed at an angle where the tangential slope of the reflectance curve was maximum. From linear regression analysis, the sensitivity of the bimetallic SPR chip with respect to the CEA in critical concentration was obtained.

• Tuberculosis and Respiratory Diseases
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• 제60권4호
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• pp.412-418
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• 2006

연구배경 : 클라미디아 감염의 진단은 혈청검사로 이루어진다. 현재 표준 방법은 MIF(microimmunofluorescence)이나 이 방법은 주관적이고 시간이 많이 걸리는 단점이 있다. 최근을 SPR(surface plasmon resonance) 센서를 이용한 단백질 칩이 감염의 새로운 진단 방법으로 제시되고 있다. 클라미디아 감염의 진단을 위한 단백질 칩 개발을 위하여 금 칩 표면에 세균을 고정하고 클라미디아 균에 대한 항체와 표면 위 세균과의 반응을 SPR 센서를 이용하여 측정하고자 하였다. 방법 : 표면 항원으로 배양한 Chlamydophila pneumoniae LKK1의 EB를 정제하였다. 양전하를 띤 PDDA (polydiallyldimethylammonium chloride)를 이용하여 전하를 이용한 단백질 칩을 제작하였다. 클라미디아 균을 고정시킨 후에 atomic force microscopy를 이용하여 표면을 관찰하였다. 클라미디아 균에 대한 항체를 투여하고 나서 자체 제작한 SPR 센서를 이용하여 항원 항체 반응을 SPR 파장 변화로 측정하였다. 결과 : 양전하를 띤 PDDA 표면위에서 클라미디아 균이 고정되었음을 확인 하였다. 그리고, 항체를 투여한 후에 SPR 파장의 증가를 확인하였다. 파장 변화는 항원의 농도와 관련이 있었다. 결론 : 전하를 이용하여 클라미디아 폐렴균의 EB를 단백질 칩에 고정하였고, 단백질 칩 위에서의 항원 항체 반응을 확인하였다. 비정형 폐렴의 진단에 SPR 센서가 기여할 수 있을 것으로 사료되나, 실제 임상 시료에의 적용을 위해서는 좀더 연구가 필요할 것으로 사료된다.

• 센서학회지
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• 제24권6호
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• pp.423-428
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• 2015

A bimetallic chip made of gold and silver was investigated in intensity interrogation mode to confirm enhancement of the SPR sensor resolution. Both reflectance curves of the bimetallic chip and the conventional gold chip was acquired and compared. The line width of the reflectance curve of the bimetallic chip was narrower than that of the conventional Au chip, resulting in steeper tangential slope. The reflectance was monitored at the angle related to the steepest tangential slope. The change in reflectance of the bimetallic chip was larger than that of the Au chip. The critical angle was analyzed by differentiating the reflectance with respect to incident angle twice. Acquiring the critical angle regarding to the sample informs the refractive index of the sample. Using various concentration of Bovine Serum Albumin, we confirmed that refractive index was linearly related to variation of reflectance of the bimetallic chip.

• 센서학회지
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• 제20권6호
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• pp.434-438
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• 2011

A portable surface plasmon resonance(SPR) based immunosensor using thiolated protein G and protein G was developed for the detection of immunoglobulin G(IgG). The protein G has specific affinity with Fc fragment of IgG and was thiolated by 2-Iminothiolane for introduction of thiol groups. Anti-IgG, bovine serum albumin(BSA), and IgG have been sequently injected after surface modification of gold sensor chip with protein G and thiolated protein G. The output signal was increased with the injection of each protein and the actual signal was measured by subtracting signal of reference channel from signal of sample injected channel. The experimental results showed the higher detection capability of IgG using thiolated protein G compared with protein G. From these results, we can conclude that the current surface modification technique and the portable SPR sensor system can be applied to various immunosensors for diagnosis.

• 센서학회지
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• 제22권2호
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• pp.144-149
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• 2013

In this research, we developed a biosensor to detect lung cancer-specific biomarker using Anodic Aluminum Oxide (AAO) chip based on interference and nano surface plasmon resonance (nanoSPR). The nano-porous AAO chip was fabricated $2{\mu}m$ of pore-depth by two-step anodizing method for surface uniformity. NanoSPR has sensitivity to the refractive index (RI) of the surrounding medium and also provides simple and label-free detection when specific antibodies are immobilized to the Au-deposited surface of nano-porous AAO chip. To detect the lung cancer-specific biomarker, antibodies were immobilized on the surface of the chip by Self Assembled Monolayer (SAM) method. Since then lung cancer-specific biomarker was applied atop the antibodies immobilized layer. The specific reaction of the antigen-antibody contributed to the change in the refractive index that cause shift of resonance spectrum in the interference pattern. The Limit of Detection (LOD) was 1 fg/ml by using our nano-porous AAO biosensor chip.

• 센서학회지
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• 제17권5호
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• pp.369-374
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• 2008

A novel fiber optic surface plasmon resonance (SPR) sensor using cyclic olefin copolymer (COC) prism with the spectral modulation is presented. The SPR sensor chip is fabricated using the SU-8 photolithography, Ni-electroplating and COC injection molding process. The sidewall of the COC prism is partially deposited with Au/Cr (45/2.nm thickness) by e-beam evaporator, and the thermal bonding process is conducted for micro fluidic channels and optical fibers alignment. The SPR spectrum for a phosphate buffered saline (0.1.M PBS, pH.7.2) solution shows a distinctive dip at 1300.nm wavelength, which shifts toward longer wavelength with respect to the bovine serum albumin (BSA)concentrations. The sensitivity of the wavelength shift is $1.16\;nm{\cdot}{\mu}g^{-1}{\cdot}{\mu}l^{-1}$. From the wavelength of SPR dips, the refractive indices (RI) of the BSA solutions can be theoretically calculated using Kretchmann configuration, and the change rate of the RI was found to be $2.3{\times}10^{-5}RI{\cdot}{\mu}g^{-1}{\cdot}l^{-1}$. The realized fiber optic SPR sensor with a COC prism has clearly shown the feasibility of a new disposable, low cost and miniaturized SPR biosensor for biochemical molecular analyses.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.413-417
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• 2000

In this study, a direct detection system for triazine derivative herbicides was developed using the photosynthetic reaction center (RC) from the purple bacterium, Rhodobacter sphaeroides, and surface plasmon resonance (SPR) apparatus. The histidine-tagged RCs were immobilized on an SPR gold chip using nickel-nitrilotriacetic acid groups as a binder for one of the triazine herbicide, atrazine. The SPR responses were proportional to the sample concentrations of atrazine in the range 0.1-1 $\mu\textrm{g}$/mL. The sensitivity of the direct detection of atrazine using the RC-assembled sensor chip was higher than that using the antibody-immobilized chip. The other types of herbicides, DCMU or MCPP, were not detected with such high sensitivity. The results indicated the high binding selectivity of the RC complex.