Performance Characteristics of a Urea Microsensor Employing a Micromachined Carbon Dioxide Electrode

Suzuki, Hiroaki; Arakawa, Hiroaki; Karube, Isao

doi:10.1002/1521-4109(200011)12:16<1327::aid-elan1327>3.0.co;2-q

Cited by 8 publications

(6 citation statements)

References 33 publications

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“…For pyruvate measurement in serum, a miniature redox hydrogel-based sensor, which was not influenced by the oxygen concentration in sample, was developed using electrically wired recombinant PyrOx [363]. For urea determination an enzyme-based field-effect transistor was developed based on immobilization of urease within two different clay matrixes, one cationic (laponite) and the other anionic (layered double hydroxide), cross-linked by glutaraldehyde [364]; a urea microsensor employing a micromachined carbon dioxide electrode has also been developed [365]. In this sensor, the detecting electrode patterns were formed on a glass substrate and the container for the electrolyte solution was formed on a silicon substrate by anisotropic etching.…”

Section: Sensors For Other Body Constituentsmentioning

confidence: 99%

Current research activity in biosensors

Nakamura

Karube

2003

Analytical and Bioanalytical Chemistry

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129

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Biosensors consist of a molecular recognition element and a transducer. Since the first biosensor was developed by Updike and Hicks many biosensors and their associated techniques have been studied and developed. In this review current research activity on the fundamentals and applications of biosensors is summarized. In discussion of the former, molecular recognition elements, techniques and tools for biosensor construction, and basic biosensor devices are introduced. Coverage of the latter includes description of biosensors for environmental, food, and clinical fields. Chemical sensors developed in our laboratory for environmental monitoring are also described. This review mainly summarizes work performed by our group and by our colleagues, and refers to the main review articles summarizing each field of biosensor research in recent years.

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Section: Sensors For Other Body Constituentsmentioning

confidence: 99%

Current research activity in biosensors

Nakamura

Karube

2003

Analytical and Bioanalytical Chemistry

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261

129

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“… 28 The Severinghaus-based urea sensor required 12–30 min analysis time, depending on the urea concentration. 26 …”

Section: Resultsmentioning

confidence: 99%

“…Urea detection through CO 2 as its hydrolysis product can be considered less attractive because of different speciations of CO 2 at different pH values. Suzuki et al constructed a urea biosensor based on urease in front of a Severinghaus-type CO 2 sensor. This sensor had a quite low limit of detection (LOD), however, bearing the disadvantages of Severinghaus sensors of slow response and unstable calibration curves, especially at low CO 2 concentrations .…”

Section: Resultsmentioning

confidence: 99%

“…28 The Severinghaus-based urea sensor required 12−30 min analysis time, depending on the urea concentration. 26 The newly developed CO 2 microsensor has superior characteristics as compared to the Severinghaus-type sensors. Our CO 2 microsensor-based urea sensor using cross-linked urease/BSA/alginate/glutaraldehyde/Ca 2+ in the front enzyme chamber exhibits a linear response to urea concentration from 0 to 1000 μM with a calculated LOD of 0.94 μM (3× blank SD/slope of calibration curve).…”

Section: ■ Introductionmentioning

confidence: 99%

“…No reports of long-term exposure to complex media such as blood serum could thus be found. A solution to this challenge is to apply CO 2 monitoring based on Severinghaus-type CO 2 sensors. − Severinghaus-type sensors are based on diffusion of dissolved CO 2 through a gas permeable membrane, resulting in a pH change in a buffer behind this membrane . Electrode fouling substances such as proteins cannot penetrate the polymer membrane, and there should thus be basis for better long-term stability in complex media.…”

Section: Introductionmentioning

confidence: 99%

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Urea Biosensor Based on a CO₂ Microsensor

et al. 2020

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Urea sensors based on electrodes in direct contact with the medium have limited long-term stability when exposed to complex media. Here, we present a urea biosensor based on urease immobilized in an alginate polymer, buffered at pH 6, and placed in front of a newly developed fast and sensitive CO 2 microsensor, where the electrodes are shielded by a gas-permeable membrane. The CO 2 produced by the urease in the presence of urea diffuses into the microsensor and is reduced at a Ag cathode. Oxygen interference is prevented by a Cr 2+ trap. The 95% response time to changes in urea concentration was 120 s with a linear calibration curve in the range 0–1000 μM and a detection limit of 1 μM. The Ni 2+ cofactor to improve sensor performance was continuously supplied from a reservoir behind the sensor tip. The stability of the urea sensor was optimized by the addition of bovine serum albumin as a stabilizer to the urease/alginate mixture that was cross-linked with glutaraldehyde and Ca 2+ ions. This immobilization strategy resulted in about 70% of the initial urea sensor sensitivity after two weeks of continuous operation. The sensor was successfully tested in blood serum.

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A multi‐functional electrochemical sensing system using microfluidic technology for the detection of urea and creatinine

et al. 2011

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This study presents a new microfluidic system capable of precise measurements of two important biomarkers, urea and creatinine, automatically. In clinical applications, high levels of these two biomarkers are early indicators of nephropathy or renal failure and should be monitored on a regular basis. The microfluidic system is composed of a microfluidic chip, a control circuit system, a compressed air source and several electromagnetic valves to form a handheld system. The microfluidic chip is fabricated by using micro-electromechanical systems and microfluidic techniques comprising electrochemical sensor arrays and polydimethylsiloxane-based microfluidic structures such as micropumps/micromixers, normally closed valves and microchannels. The microfluidic system performs a variety of critical processes including sample pretreatment, mixing, transportation and detection on a single chip. The experimental results show that the entire procedure takes approximately 40 min, which is much faster than the traditional method (more than 6 h). Furthermore, the total sample volume consumed in each operation is only 0.1 mL, which is significantly less than that required in a large system (5 mL). The developed automatic microfluidic system may provide a powerful platform for further clinical applications.

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Performance Characteristics of a Urea Microsensor Employing a Micromachined Carbon Dioxide Electrode

Cited by 8 publications

References 33 publications

Current research activity in biosensors

Current research activity in biosensors

Urea Biosensor Based on a CO₂ Microsensor

A multi‐functional electrochemical sensing system using microfluidic technology for the detection of urea and creatinine

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Performance Characteristics of a Urea Microsensor Employing a Micromachined Carbon Dioxide Electrode

Cited by 8 publications

References 33 publications

Current research activity in biosensors

Current research activity in biosensors

Urea Biosensor Based on a CO2 Microsensor

A multi‐functional electrochemical sensing system using microfluidic technology for the detection of urea and creatinine

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Urea Biosensor Based on a CO₂ Microsensor