• Journal of Biosystems Engineering
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• 제34권1호
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• pp.50-56
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• 2009

Surface plasmon resonance (SPR) biosensor has been used to detect many biochemical reactions, because this label-free sensor has high sensitivity and rapid response. The reactions are monitored by refractive index changes of the SPR biosensor. Iprovalicarb is protective, curative, and eradicative systemic fungicide introduced by Bayer AG in 1999. It has potential far control of downy mildew infesting onion, cucumber, grape and melon, late blight infesting tomato and potato, and anthracnose infesting watermelon and pepper. It is strictly limited to the maximum residue limit. In this study, the applicability of a portable SPR biosensor (Spreeta, Texas instrument, TX, USA) to detect the iprovalicarb residue was examined. The sensor chip was adopted to detect the reaction of iprovalicarb to immobilized iprovalicarb-antibody. The binding of the iprovalicarb onto the biosensor surface was measured by change of the refractive index (RI). Characteristics of the sensor chip including specificity, sensitivity, stability, and reusability were analyzed. In calibration test for seven levels of iprovalicarb concentration (0.32 to 5,000 mg/L) with three replications, a Sigmoidal model with Hill function was obtained between relative RI value and the iprovalicarb concentration with R-square of 0.998. It took 30 minutes to complete a set of detecting assay with the SPR biosensor.

• Preventive Nutrition and Food Science
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• 제4권1호
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• pp.79-83
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• 1999

A potentiometric biosensor employing a CO3-2 ion-selective electrode(ISE) and malic enzyme immobilization in al flow injection analysis (FIA) system was constructed. Analytical parameters were optimized for L-malate determination . The CO3-2 -ISE-FIA system was composed of a pump, an injector, a malic enzyme (EC1.1.1.40) reactor, a CO3-2 ion-selective electrode, a pH/mV meter and a recorder. Cofactor NADP was also injected with substrate for theenzyme reaction into the system. Optimized analytical parameters for L-malate determination in the CO3-2 ISE-FIA system were as follows ; flow rate, 14.5ml/hr ; sample injection volume, 100ul; enzyme loading in the reactor, 20 units ; length of the enzyme reactor , 7 cm ; tubing length form the enzyme reactor to the detector as a geometric factor in FIA, 15 cm . The response time for measuring the entire L-malate concentration range (10-2 ~10-5 mol/L ; 4 injections )was <15minutes . In this CO3-2 -ISE-FIA system, the potential differences due to th eformation of CO3-2 by the reaction of malic enzyme on L-malate were correlated to L-malate concentration in the range of 10-2 ~10-5mol/L ; the detection limit was 10-5 mol/L. This potentionmetric CO3-2 ISE--FIA system was found to be useful for L-malate measurement.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.388-391
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• 2004

A sol-gel fiber-optic biosensor with encapsulated pH-sensitive fluorophore and immobilized genetically modified toluene-o-xylene monooxygenase was developed to detect TCE and PCE, which are carcinogenic chlorinate organic compounds prevailing in ground water. The sensitivity was characterized for the composition of sol-gel, and manufacturing procedure. The intensity curve reveals a linear range of intensity for pollutant concentration range of 0.01ppm and 1ppm. The change in intensity was appeared to be larger at each of L for same condition, and, therefore, the wavelength of λ was chosen for the analytical measurement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.93-94
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• 2006

In this research, the enhancement of electron-transfer activity of hemoglobin (Hb) in dodecanoic acid film was investigated for the first time. This type of composite film was made on glassy carbon electrode by casting method. Cyclic voltammetric result of the modified electrode displays a well defined redox peaks which was attributed to the direct electrochemical response of Rb. Our results illustrate that Rb exchange electrons directly with electrode and exhibits the characteristics of peroxidase. When we apply this modified electrode as a biosensor, it gives excellent performances in the electrocatalytic reduction of hydrogen peroxide ($H_{2}O_{2}$). Through the optimal conditions, the proposed biosensor shows the linear range for H2O2 determination was from $1{\times}10^{-5}$ to $1.25{\times}10^{-4}mol/L$ with a detection limit of $1{\times}10^{-7}mol/L$. The biosensor retained more than 90% of the initial response after 14 days.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.17.1-17.1
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• 2011

Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as a type of implantable LED biosensor and as a therapy tool.

• Journal of the Optical Society of Korea
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• 제13권3호
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• pp.392-397
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• 2009

We designed a wavelength interrogation-based surface plasmon resonance (SPR) biosensor to detect avian influenza DNA (AI-DNA). Hybridization reactions between target AI-DNA probes and capture probes immobilized on a gold surface were monitored quantitatively by measuring the resonance wavelength in the visible waveband. The experimental results were consistent with numerical calculations. Although the SPR detection technique does not require the DNA to be labeled, we also evaluated fluorescently-labeled targets to verify the hybridization behavior of the AI-DNA. Changes in resonance were found to be linearly proportional to the amount of bound analyte. A wavelength interrogation-type SPR biosensor can be used for rapid measurement and high-throughput detection of highly pathogenic AI viruses.

• 한국식품과학회지
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• 제29권6호
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• pp.1075-1081
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• 1997

L-Glutamate를 간편하고 단시간에 측정할 수 있는 glutamate sensor를 개발하기 위하여, glutamate oxidase를 여러 가지 membranes에 고정화 시키는데 적합한 조건과. 그 결과로 얻은 효소 membranes의 특성, 개발한 glutamate sensor의 반응특성 및 glutamate sensor의 정확성을 조사하였다. Glutamate oxidase를 membranes에 고정화 하는데 GA 0.25%, BSA 0.3 mg, 효소 사용량 2.0 units이상이 적당하였다. 고정화 효소의 최적 pH는 6.5이었고, chitosan membrane을 사상한 경우 가장 효소활성이 높았다. 그러나 저장 안정성이나 반응시간 등을 고려하여 preactivated nylon에 고정화시킨 효소 membrane을 glutamate sensor 개발에 사용하였다. Glutamate oxidase를 선택한 membrane에 고정화시켜 효소와 glutamate의 반응산물인 암모니아가 nonactin membrane을 이용한 암모니움이온 전극에 의하여 측정되도록 효소 sensor를 구성하였으며, sensor의 반응시간은 약 2분이었다. Preactivated membrane에 고정화된 효소는 $4^{circ}C$에서 2개월간 저장중 안정한 활성을 보였으며, 이를 사용한 glutamate sensor로 약 250회 측정할 때 까지 활성에 별 변화가 없었다, 개발된 glutamate sensor의 glutamate 측정 농도범위는 $0.1{\sim}5\;mM$ 이었다. Glutamate sensor를 체더 치즈중의 L-glutamate 측정에 응용한 결과는 HPLC로 분석한 결과와 높은 상관관계가 있어, 정확성이 인정되었다.

• KSBB Journal
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• 제9권3호
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• pp.319-324
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• 1994

옥수수잎의 유관속초세포 내에 존재하는 malate dehydrogenase(EC 1.1.1.40)을 이용하여 malate 정량용 biosensor를 제작한 후, 기질인 malate에 대하여 여러 가지 조건하에서 측정한 결과, sodium-alginate로 고정화한 것이 하지 않은 것보다 180시 간까지 지나도 40% 이상의 activity를 가지며, 최적 pH는 8.0이었으며 pH 7.4에서 Km치는 $0.6{\times}10^{-5}M$이였다. 전극의 안정성은 연주일 이상 측정이 가능하였으며, 정량 가능한 범위는 $5.5{\times}10^{-5}M∼2.5{\times}10^{-2}M$ 이며, 감응도는 53.7mv/decade이고, 측 정소요시간은 16~18분이 소요되였다. 방해물질로서 각종 염의 영향은 크게 받지 않음을 알았다. 본 연구에서 제작한 조직 biosensor는 효소분리과정을 거치지 않고 조직을 이용하여 malate흘 정량하였다는 것과 지금까지 연구된 효소 바이오센셔와는 랄리 강산성에셔 측정하던가, 한 가지 이상의 효소를 사용하지 않고도 중성영역인 pH=8에서 측정이 가능 하였으며, malate를 탈수소화하여 정량한 연구는 많았지만, 탈탄산화하여 정량한 연구는 없었다. 본 연구에서 제작한 조직바이오센셔는 malate 측정용 sensor로 가능하리라 생각된다.

• 생명과학회지
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• 제21권9호
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• pp.1323-1328
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• 2011

본 연구에서는 페놀 화합물들을 현장에서 검출하기 위해 간단하고 간편한 일회용 재조합 박테리아 바이오센서 시스템을 개발하였다. 플라즈미드 pLZCapR을 함유하는 E. coli 세포를 ${\beta}$-galactosidase 기질인 CPRG와 함께 96-well plate의 wells에 agarose로 고정하였다. 이 바이오센서는 현장에서 발색을 위한 별도의 기질을 추가하거나 불편한 기기 사용 또는 시료의 전 처리를 필요로 하지 않는다. 시료의 측정은 간단히 적은 부피(<100 ${\mu}l$)의 현장 시료를 바이오센서를 포함하는 wells에 넣고 발색을 관찰하여 측정하였다. 또한 6% DMF, 0.1% SDS 그리고 10 mM $CaCl_2$를 첨가하여 agarose 고정에 의한 화합물의 세포내 확산 제한을 감소시켜 보다 더 나은 발색을 얻을 수 있었다. 따라서 이 고정된 미생물 유래 재조합 바이오센서 시스템은 현장에서 환경오염물질들을 간단하게 확인하고 정량 하는 유용한 접근 방법이 될 것으로 사료된다.

• Food Science and Biotechnology
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• 제16권3호
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• pp.337-342
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• 2007

Conventional methods for pathogen detection and identification are labor-intensive and take days to complete. Biosensors have shown great potential for the rapid detection of foodborne pathogens. Fiber-optic biosensors have been used to rapidly detect pathogens because they can be very sensitive and are simple to operate. However, many fiber-optic biosensors rely on manual sensor handling and the sandwich assay, which require more effort and are less sensitive. To increase the simplicity of operation and detection sensitivity, a binding inhibition assay method for detecting Listeria monocytogenes in food samples was developed using an automated, fiber-optic-based immunosensor: RAPTOR (Research International, Monroe, WA, USA). For the assay, fiber-optic biosensors were developed by the immobilization of Listeria antibodies on polystyrene fiber waveguides through a biotin-avidin reaction. Developed fiber-optic biosensors were incorporated into the RAPTOR to evaluate the detection of L. monocytogenes in frankfurter samples. The binding inhibition method combined with RAPTOR was sensitive enough to detect L. monocytogenes ($5.4{\times}10^7\;CFU/mL$) in a frankfurter sample.