• 센서학회지
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• 제22권5호
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• pp.346-351
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• 2013

We developed a one-step method for fabrication of addressable suspended SWNT films and demonstrate excellent detection performance of paraoxon based on OPH-immobilized SWNT films for environmental monitoring. For dispersed SWNT suspension, COOH-SWNT was prepared by the oxidation of carbon nanotubes using acid treatment and sonication. Suspended SWNT-film was fabricated between cantilever electrodes by dielectrophoretic force and surface tension of the water meniscus. After that, OPH were immobilized on suspended SWNT-films by nonspecific binding for enzymatic hydrolysis of paraoxon. The electrical properties of the SWNT films were measured in real time at room temperature. Structurally suspended SWNT films from substrate surface made possible rapid and highly sensitive detection of target molecules with increased convectional and diffusional fluxes of the molecules and with a large binding surface area. SWNT film FET resulted in a real-time, label-free, and electrical detection of paraoxon to the concentration of ca. $10{\mu}m$ with a step-wise rapid response time of several seconds.

• KSBB Journal
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• 제17권2호
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• pp.158-161
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• 2002

본 연구에서는 화학무기, 농약 등에 사용되는 신경독성물질인 유기인화합물의 측정을 위하여 유기인화합물의 효소반응 저해작용을 이용한 광바이오센서장치의 시제품을 제작하였다. 효소반응을 위하여 효소로는 신경세포의 필수효소인 acetylcholinesterase, acetylthiocholine iodide을 사용하였으며 효소반응의 저해제인 유기인화합물로는 paraoxon을 사용하였다. 센서의 폭정원리는 유기인화합물에 의해 저해된 효소반응정도를 효소반응의 생성물인 아세트산의 정량적 측정으로 분석하였으며, pH에 의하여 최대 흡광파장의 변화가 일어나는 litmus를 사용하여 흡광도 측정으로 아세트산의 정량분석을 수행하였다. 광바이오센서 시제품의 제작은 광원으로 고취도 LED와 광세기 측정을 위한 photodiode로 구성하였으며, 제작된 센서를 이용한 실험결과로부터 0 ppm에서 2 ppm의 paraoxon 농도에서 구성된 센서시스템의 선형적 신호 변화를 관찰하였다. 이상의 실헐결과로부터 광바이오센서 시제품은 2분의 반응시간으로 신속하고 정확한 유기인화합물의 정량분석이 가능함을 확인하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.496-496
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• 2005

• BMB Reports
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• 제31권3호
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• pp.296-302
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• 1998

A potentiometric flow injection biosensor for the analysis of anti-cholinesterases (anti-ChEs), based on inhibition of enzyme activity, was developed. The sensor system consists of a reactor with acetylcholinesterase (AChE) immobilized on controlled pore glass and a detector with an $H^{+}-selective$ PVC-based membrane electrode. The principle of the analysis is based on the fact that the degree of inhibition of AChE by an anti-ChE is dependent on the concentration of the anti-ChE in contact with AChE. The sensor system was optimized by changing systematically the operating parameters of the sensor to evaluate the effect of the changes on sensor response to ACh. The optimized biosensor was applied to the analysis of paraoxon, an organophosphorus pesticide. Treatment of the inhibited enzyme with pyridine-2-aldoxime fully restored the enzyme activity allowing repeated use of the sensor.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.1-14
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• 2023

The overuse of pesticides in agricultural sectors exposes people to food contamination. Pesticides are toxic to humans and can have both acute and chronic health effects. To protect food consumers from the adverse effects of pesticides, a rapid monitoring system of the residues is in dire need. Molecularly imprinted polymer (MIP) on a screen-printed electrode (SPE) is a leading and promising electrochemical sensing approach for the detection of several residues including pesticides. Despite the huge development in analytical instrumentation developed for contaminant detection in recent years such as HPLC and GC/MS, these conventional techniques are time-consuming and labor-intensive. Additionally, the imprinted SPE detection system offers a simple portable setup where all electrodes are integrated into a single strip, and a more affordable approach compared to MIP attached to traditional rod electrodes. Recently, numerous reviews have been published on the production and sensing applications of MIPs however, the research field lacks reviews on the use of MIPs on electrochemical sensors utilizing the SPE technology. This paper presents a distinguished overview of the MIP technique used on bare and modified SPEs for the detection of pesticides from four recent publications which are malathion, chlorpyrifos, paraoxon and cyhexatin. Different molecular imprint routes were used to prepare these biomimetic sensors including solution polymerization, thermal polymerization, and electropolymerization. The unique characteristics of each MIP-modified SPE are discussed and the comparison among the findings of the papers is critically reviewed.

• 센서학회지
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• 제23권1호
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• pp.35-41
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• 2014

Microbes have been used extensively in various fields of researches and industries but has not been used widely for microfluidic biosensor applications because it is difficult to immobilize properly to a small space. Therefore, we developed a microbial immobilization method for microfluidic devices using single-walled nanotubes and dielectrophoretic force. Single-walled nanotubes and Escherichia coli were aligned between two cantilever electrodes by a positive dielectrophoretic force resulting in a film of single-walled nanotubes with attached Escherichia coli. The optimal condition of film formation without a cell lysis was investigated. Diameter of single-walled nanotubes and electric field (intensity and duration of application) had an effect on the cell viability. On the other hand, the cell concentration of the suspension did not affect the cell viability. Paraoxon was detected using single-walled nanotubes film with attached Escherichia coli that expressed organophosphorus hydrolase. This film which is suspended from the substrate showed faster response time than sensors that are not suspended from the substrate.