• International Journal of Oral Biology
• /
• 제36권2호
• /
• pp.103-108
• /
• 2011

Measurement of estrogen concentration in bio-samples are very important for differential diagnosis of various disease or evaluation of health status. However, it is difficult to collect immediate data of estrogen concentration because they are measured by radioimmunoassay or chromatography which need time- and cost-consuming sample pre-treatment. This study was performed for development of new estrogen biosensor employing taste principles, and for evaluation of cross reactivity between various steroid hormones. Gene sequence of ligand binding domain of ${\alpha}$-human estrogen receptor (amino acid 302-553; hER-LBD) was cloned from human breast cancer cell line. The proteins of hER-LBD were produced by T7-E.coli expression system, and isolated by chromatography. hER-LBD were coated on the gold plated quartz crystal (AT-cut 9MHz), and resonance frequencies were measured by universal frequency counter. Estradiol, progesterone, testosterone, and aldosterone were used for cross reactivity of the hER-LBD. We also monitored influences of pH change in resonance frequency. The resonance frequencies of hER-LBD coated quartz crystal were decreased during increase of estrogen concentration from $15 \;{\mu}g/mL$ to $50\;{\mu}g/mL$. However, similar steroid hormones, progesterone and aldosterone, did not elicit the change in resonance frequency. Testosterone evoke weak change in resonance frequency. The new estrogen biosensor was more sensitive in pH 7.2 than in pH 7.6. These results suggest that hER-LBD coated quartz crystal biosensor is a probable estrogen biosensor.

• Journal of Biosystems Engineering
• /
• 제31권6호
• /
• pp.535-540
• /
• 2006

For a biosensor development, an enzyme-linked immunosorbent assay (ELISA) of the fungicide iprovalicarb was developed by minimizing the processing time. The time for whole incubation process was reduced from 135 minutes to 15 minutes. The concentration of antibody was varied to improve sensitivity. The total processing time was reduced from 2.5 hours to 20 minutes, the final sensitivity ($IC_{50}$ value) of 7.93 ng/mL and the lowest detection limit of 0.045 ng/mL were obtained. This ELISA was applied to potatoes and onions, and the recoveries were in the range of 98.85 $\sim$ 101.20% and 87.97 $\sim$ 102.70%, respectively. Accordingly, this method can be used as basis for a biosensor for rapid monitoring of iprovalicarb residues in crops.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제23권4호
• /
• pp.42-47
• /
• 2018

E. coli TG1 pBS TOM Green was cultured to produce toluene-o-monooxygenase (TOM). A biosensor system was successfully constructed using purified TOM to effectively detect trichloroethene (TCE) and tetrachloroethene (PCE), which represent some of the major contaminants in groundwater and soil. In order to utilize TOM as a sensor, NADH, a biological oxidizer, was replaced with hydrogen peroxide which is a chemical oxidizing agent. A three-layered sandwich-type sensing tip was fabricated on the outside of the hydrophilic polyvinylidene fluoride membrane. TCE and PCE were applied to the sensor and the hydrogen ions were measured by a fiber optic fluorometer using fluoresceinamine. Calibration curves were obtained for TCE and PCE in the concentration range of 0.2-100 mg/l, and the detection limit of the system was $10{\mu}g/l$ for TCE and PCE.

• Applied Science and Convergence Technology
• /
• 제25권3호
• /
• pp.61-65
• /
• 2016

Here, the rapid detection of Salmonella typhimurium by a portable surface plasmon resonance (SPR) biosensor in which the beam from a diode laser is modulated by a rotating mirror is reported. Using this system, immunoassay based on lipopolysaccharides (LPS)-specific monoclonal anti-Salmonella antibody was performed. For the purpose of orientation-controlled immobilization of antibodies on the SPR chip surface, the cysteine-mediated immobilization method, which is based on interaction between a gold surface and a thiol group (-SH) of cysteine, was adopted. As a result, using the portable SPR-based immunoassay, we detected S. typhimurium in the range from 10^7 CFU/mL to 10^9 CFU/mL within 1 hour. The results indicate that the portable SPR system could be potentially applied for general laboratory detection as well as on-site monitoring of foodborne, clinical, and environmental agents of interest.

• 분석과학
• /
• 제7권2호
• /
• pp.149-153
• /
• 1994

Squash-조직을 graphite rod disk 전극에 고정하여 메탄올 용매 속에서 L-ascorbic acid(AA)를 정량할 수 있는 전류법 바이오센서를 만들었다. 전극의 검출한계는 $2{\times}10^{-6}M$이었다. 순수한 ascorbate oxidase(AO)를 고정시켜 만든 전극에 비해 식물 조직에 들어 있는 효소로 만든 이 전극은 생촉매의 활성도가 높고 안정성이 좋았으며(1주간) 대단히 값싸게 만들 수 있었다.

• 한국식품과학회지
• /
• 제38권2호
• /
• pp.169-175
• /
• 2006

Citrate Iyase(CL)와 oxaloacetate decarboxylase(OD)를 고정화하여 효소 반응기를 제작하고 효소반응으로 생성된 carbonate ion을 ion selective electrode를 이용한 전위차법 FIA system으로 식품에함유된 구연산의 농도를 측정하였다. 최적 센서 시스템의 조건은 CL과 OD을 같이 고정화시키는 방법으로 CL과 OD의 양이 각각 10 units, 60 units, 담체량은 0.3 g, carrier buffer 1(0.1 MTris buffer)은 pH 7.5, carrier buffer의 유속은 12 mL/hr으로 결정되었다. 최적 상태에서의 표준검량곡선은 $10^{-1}\;M-10^{-3}\;M$ 범위에서 직선적인 상관관계$(r^2=0.9986)$를 나타내었다. 당류와 유기산류에 대한 센서 시스템에 대한 방해효과를 측정한 결과 당류는 거의 저해효과를 보이지 않았으며 유기산의 경우도 저해 효과가 5% 미만으로 이들 물질에 의해 감응도가 크게 방해받지 않은 것으로 나타났다. 구연산 바이오센서와 GC를 사용하여 식품 시료에 함유된 구연산의 농도를 분석한 결과 두 방법간에 유의적인 차이가 없는 것으로 나타나 본 연구에서 구축한 구연산 바이오센서 시스템은 식품에 함유된 구연산 분석시 신뢰성 있는 결과를 주는 것으로 보여졌다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제9권2호
• /
• pp.118-126
• /
• 2004

Recombinant E.coli ACV 1003 (recA::lacZ) releasing ${\beta}$-galactosidase by a SOS regulon system, when exposed to DNA-damaging compounds, have been used to effectively monitor endocrine disruptors. Low enzyme activity of less than 10 units/mL, corresponding to a $\mu\textrm{g}$/L(ppb) range of an endocrine disruptor (tributyl tin, bisphenol A. etc.), can be rapidly determined, not by a conventional time-consuming and tedious enzyme assay, but by an alternative interferometric biosensor. Heavily boron-doped porous silicon for application as an interferometer, was fabricated by etching to form a Fabry-Perot fringe pattern, which caused a change in the refractive index of the medium including ${\beta}$-galactosidase. In order to enhance the immobilization of the porous silicon surface, a calyx crown derivative (ProLinker A) was applied, instead of a conventional biomolecular affinity method using biotin. This resulted in a denser linked formation. The change in the effective optical thickness versus ${\beta}$-galactosidase activity, showed a linear increase up to a concentration of 150 unit ${\beta}$-galactosidase/mL, unlike the sigmoidal increase pattern observed with the biotin.

• Food Science and Biotechnology
• /
• 제17권5호
• /
• pp.1038-1046
• /
• 2008

This study was carried out to develop a small-sized biosensor based on surface plasmon resonance (SPR) for the rapid identification of insecticide residues for food safety. The SPR biosensor module consists of a single 770 nm-light emitting diodes (LED) light source, several optical lenses for transferring light, a hemisphere sensor chip, photo detector, A/D converter, power source, and software for signal processing using a computer. Except for the computer, the size and weight of the sensor module are 150 (L)$\times$70 (W)$\times$120 (H) mm and 828 g, respectively. Validation and application procedures were designed to assess refractive index analysis, affinity properties, sensitivity, linearity, limits of detection, and robustness which includes an analysis of baseline stability and reproducibility of ligand immobilization using carbamate (carbofuran and carbaryl) and organophosphate (cadusafos, ethoprofos, and chlorpyrifos) insecticide residues. With direct binding analysis, insecticide residues were detected at less than the minimum 0.01 ppm and analyzed in less than 100 sec with a good linear relationship. Based on these results, we find that the binding interaction with active target groups in enzymes using the miniaturized SPR biosensor could detect low concentrations which satisfy the maximum residue limits for pesticide tolerance in Korea, Japan, and the USA.

• Food Science and Biotechnology
• /
• 제18권1호
• /
• pp.89-94
• /
• 2009

Frequent outbreaks of foodborne illness have been increasing the awareness of food safety. Conventional methods for pathogen detection and identification are labor-intensive and take days to complete. Some immunological, rapid assays are developed, but these assays still require prolonged enrichment steps. Recently developed biosensors have shown potential for the rapid detection of foodborne pathogens. In this study, an impedimetric biosensor was developed for rapid detection of Salmonella entritidis in food sample. To develop the biosensor, an interdigitated microelectrode (IME) was fabricated by using a semiconductor fabrication process. Anti-Salmonella antibodies were immobilized based on neutravidin-biotin binding on the surface of the IME to form an active sensing layer. To evaluate the effect of electrode gap on sensitivity of the sensor, 3 types of sensors with different electrode gap sizes (2, 5, and $10{\mu}m$) were fabricated and tested. The impedimetric biosensor could detect $10^3\;CFU/mL$ of Salmonella in pork meat extract with an incubation time of 5 min. This method may provide a simple, rapid, and sensitive method to detect foodborne pathogens.

• Preventive Nutrition and Food Science
• /
• 제3권1호
• /
• pp.36-42
• /
• 1998

Ion-selective eleltrodes(ISEs) are simple electrodechemical devices for the direct measurement of ions in the samples. A novel potentiometric biosensor for the determination of L-Malate or D-isocitrate has been developed by using CO2-3 -ISE-FIA system was composed of a pump, an injector, a malic enzyme or isocitric dehydrogenase enzyme reactor, a CO2-3 -ISE, a pH/mV meter, and an integrater. The various factors, such as buffer capacity types of plstericizer and polymer, were optimized for the CO2-3 selectivity. In this novel CO2-3 --ISE-FIA system, the potential difference due to the amount of CO2-3 produced from each enzyme reaction was proportional to the amount of L-malate or D-isocitrate.