• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3128-3132
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• 2010

A disposable solid-state pH sensor was realized by utilizing two nanoporous Pt (npPt) electrodes and a copolyelectrolytic junction. One nanoporous Pt electrode was to measure the pH as an indicating electrode (pH-IE) and the other assembled with copolyelectrolytic junction was to maintain constant open circuit potential ($E_{oc}$) as a solid-state reference electrode (SSRE). The copolyelectrolytic junction was composed of cationic and anionic polymers immobilized by photo-polymerization of N,N'-methylenebisacrylamide, making buffered electrolytic environment on the SSRE. It was expected to make. The nanoporous Pt surrounded by a constant pH excellently worked as a solid state reference electrode so as to stabilize the system within 30 s and retain the electrochemical environment regardless of unknown sample solutions. Combination between the SSRE and the pH-IE commonly based on nanoporous Pt yielded a complete solid-state pH sensor that requires no internal filling solution. The solid state pH sensing chip is simple and easy to fabricate so that it could be practically used for disposable purposes. Moreover, the solid-state pH sensor successfully functions in calibration-free mode in a variety of buffers and surfactant samples.

• Journal of Sensor Science and Technology
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• 제16권6호
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• pp.449-456
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• 2007

The work described in this study concerns the development of a disposable amperometric sensor for the electrochemical detection of a well-known aqueous pollutant, free available chlorine (FAC). The FAC sensor developed used screen printed carbon electrodes (SPCEs) coupled with immobilised syringaldazine, commonly used as an indicator in photometric FAC detection, which was directly immobilised on the surface of SPCEs using a photopolymer PVA-SbQ. To enable in-field analysis of FAC, a prototype hand-held electrochemical analyzer has been developed to withstand the environment with its rugged design and environmentally sealed connections; it operates from two PP3 (9 volt) batteries and is comparable in accuracy and sensitivity to commercial bench top systems. The sensitivity of the FAC sensor developed was $3.5{\;}nA{\mu}M^{-1}cm^{-2}$ and the detection limit for FAC was found to be $2.0{\;}{\mu}M$.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.310-317
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• 2020

A development of disposable strip-type galactose sensor for point-of-care testing (POCT) was studied, which was constructed using screen-printed carbon electrodes. Galactose levels were determined by the redox reaction of galactose oxidase in the presence of potassium ferricyanide as an electron transfer mediator in a small sample volume (i.e., less than 1 µL). The optimal performance of biosensor was systematically designated by varying applied potential, operating pH, mediator concentration, and amount of enzyme on the electrode. The sensor system was identified as a highly active for the galactose measurement in terms of the sensitivity (slope = 4.76 ± 0.05 nA/µM) with high sensor-to-sensor reproducibility, the linearity (R² = 0.9915 in galactose concentration range from 0 to 400 µM), and response time (t_95% = <17 s). A lower applied potential (i.e., 0.25 V vs. Ag/AgCl) allowed to minimize interference from readily oxidizable metabolites such as ascorbic acid, acetaminophen, uric acid, and acetoacetic acid. The proposed galactose sensor represents a promising system with advantage for use in POCT.

• Journal of Sensor Science and Technology
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• 제20권6호
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• pp.400-405
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• 2011

This study introduced the development of a strip type disposable enzyme-linked immunosensor platform for the detection of IgG. Strips of the strip sensor were fabricated by using commercial nitrocellulose filter membranes and a housing holder for the strips was manufactured by using a standard injection molding process for a plastic material. An IgG-urease conjugate was prepared and used for the competitive immune-binding with sample IgG. From the enzymatic reaction between the conjugated urease and urea added, ammonia was generated and caused a localized alkaline pH change on the immobilized antibody band which was coated onto the sensor strips. This pH increase subsequently caused a color change of the antibody band in the presence of a pH indicator, phenol red. Used in conjunction with a competitive immunoassay format, the intensity of the color produced is directly linked with the concentration of target analyte, IgG, and specific measurement of IgG in a lateral flow immunoassay format was achieved over the range 100 ppb to 2000 ppb IgG.

• Journal of Sensor Science and Technology
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• 제22권3호
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• pp.202-206
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• 2013

In this paper, a disposable glucose sensor was made of paper. Glucose sensor strip using carbon electrode is appropriate for the low price ones because it requires cheap materials and low cost production. Most of blood glucose sensors were developed with plastics, but it causes pollution problems. Therefore we developed disposable carbon electrode glucose sensor using paper. This sensor consists of upper and bottom plate. On the upper plate, three-dimensional channel are formed through pressing process. The fabricated paper glucose sensor shows relatively short sensing time of about 5seconds, excellent reproducibility ($R^2$=0.9558), and fabrication yield as well.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.209-213
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• 2012

Purpose: This study was performed to develop a simple, disposable thin-film optical nitrate sensor. Methods: The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore. Fluorescence intensity of the sensor increased on contact with a nitrate solution. The fluorescence response of the optical nitrate sensor was measured with a commercial fluorospectrometer. Results: The optical sensor exhibited linear response over four concentration decades. Conclusions: Nitrate ion concentrations in plant nutrient solutions can be determined by direct optical measurements without any conditioning before measurements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.950-952
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• 2003

This paper have been studied fabrication and characteristics of disposable pH sensor using MEMS technology. The sensor has two open-well structure, the container for the internal electrolyte and electrode were formed by anisotropically etching a silicon substrate. unlike currently used KCI saturated solution, the structure was introduced hydrogel which take an advantage of miniaturization, bulk product, a low price. PU and CA/TP used to measurement ion detection, one is reference membrane and the other is pH. fabricated sensor is encapsulated entirely with epoxy, finally sensor was estimated various ion sorts and pH ranges.

• Journal of Sensor Science and Technology
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• 제15권5호
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• pp.352-356
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• 2006

In this paper, we developed enzyme electrode of a new form to improve performance of disposable glucose sensor. We could fabricate electrode of Cu/Ni/Au structure which has very low electrical resistance (0.1 $\Omega$) by sticking copper film to plastic film with laminating method and electro-plated nickle and gold on it. The enzyme electrode was completed by immobilizing enzyme on the fabricated electrode. The fabricated glucose sensor has very quick sensing time as 3 seconds, and excellent reproducibility, fabrication yield as well.

• Journal of the Korean Society of Clothing and Textiles
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• 제28권3_4호
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• pp.491-498
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• 2004

Among the components of disposable diaper, the top sheet contacting with baby skin directly is usually made of nonwoven fabrics. Therefore, the tactile properties of the nonwoven fabrics are important for the skin health of infants. In this study, we have explored the surface properties of hygiene nonwoven fabrics (100% cotton spunlace, 100% tencel spunlace, 100% polypropylene (PP) thermalbonding and 100% PP Thru-air bonded carded web (TABCW)), such as friction coefficient and geometrical roughness. used by KES-F system and a laser displacement sensor. Also, we evaluated the subjective responses about the hygiene nonwoven fabrics used by a questionnaire and compared with the objective values, measured by KES-F system and a laser displacement sensor respectively. From the result, we have found that surface sensation (such as soft, smooth, and rough) and bulkiness sensation (such as spongy and fluffy) of nonwovens were represented excellently by L-SMD values which are measured by a laser displacement sensor.

• Analytical Science and Technology
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• 제12권3호
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• pp.218-223
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• 1999

A single use, screen-printed sensor for the measurement of liquid phase ethanol was developed and its electrochemical performance was investigated. Disposable type edthanol sensor was fabricated by serially screen printing the carbon paste, silverd pasted and insulator inlon a polyester substrate to pattern working and reference electrode sites and electrical contact. Alcohol dehydrogenase(ADH) or alcohol oxidase(AOD) together with appropriate electron transfer mediators was immobilized on the working electrode. To improve the sensitivity and reproducibility of carbon paste electrode, some pretreatment procedures were applied and their resultant electrochemical performance was examined. The disposable type electrochemical ethanol sensor developed in this study conveniently determines the ethanol in liquid samples such as blood and in fermentation process.