Multifunctional Flow-injection Biosensor for the Simultaneous Measurement of Creatinine, Glucose, and Urea

Rui, Chang Sheng; Ogawa, Hiroaki; Sonomoto, Kenji; Kato, Yasuhiko

doi:10.1271/bbb.57.191

Cited by 9 publications

(1 citation statement)

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“…There are some reports of biparametric flow injection systems for urea and creatinine with the enzymes immobilised on reactors for potentiometric 27 or amperometric detection. 28,29 As explained in a previous paper, 30 nephrologists are very interested in total mass of urea extracted from a patient in the course of a hemodialysis session. This parameter helps establish the effectiveness of the dialysis session.…”

Section: Creatinine Deiminasementioning

confidence: 99%

Development of a biparametric bioanalyser for creatinine and urea. Validation of the determination of biochemical parameters associated with hemodialysis

Jurkiewicz¹,

Alegret²,

Almirall³

et al. 1998

Analyst

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The construction and evaluation of an automated urea and creatinine biparametric biosystem using flow injection analysis (FIA) are described. The biosystem uses enzyme reactions that hydrolyse urea and creatinine producing ammonium ions. The enzymes used were creatinine deiminase and urease, which are immobilized covalently in flow reactors. The reactor with creatinine deiminase has the enzyme immobilized on controlled-pore glass beads, whereas urease is immobilized on a nylon open tubular reactor. Detection is realised with a flow-through ammonium ion-selective electrode with an inner solid-state contact (graphite-epoxy composite). Ammonium ions are separated from alkali ion interferents through a gas-diffusion cell. The bioanalyser is fully automated using software and electronics developed ex profeso in our laboratories. The analyser was validated off-line by measuring urea and creatinine from discrete effluent samples from hemodialysis equipment. Results agreed with concurrent analyses realised using hospital laboratory methods. There were no significant differences between the two sets of results at the 95% confidence level. Finally, the biparametric bioanalyser was validated on-line by measuring creatinine and urea levels in artificial kidney effluents. These measurements were useful in the determination of key biochemical parameters of clinical interest such as the mass of urea and creatinine extracted from the patient as well as the initial concentration of creatinine and urea in blood plasma. When the results of the bioanalyser were compared with those yielded by the usual methods, they showed no significant differences at the 95% confidence level when determining the mass of the analytes extracted by the hemodialyser or when determining the urea concentration in blood plasma. However, when measuring the creatinine concentration in blood plasma using the developed bioanalyser, significant differences appeared.

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Section: Creatinine Deiminasementioning

confidence: 99%

Development of a biparametric bioanalyser for creatinine and urea. Validation of the determination of biochemical parameters associated with hemodialysis

Jurkiewicz¹,

Alegret²,

Almirall³

et al. 1998

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Conjugated Polymer Inverse Opals for Potentiometric Biosensing

Cassagneau

Caruso

2002

Advanced Materials

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a strong decay channel in our device. For triplet±triplet annihilation to be strong, we require electron±hole recombination to be confined to a very small region inside the polymer layer, where a sufficiently high triplet density can build up. This situation is certainly possible in our hole-injection limited F8BT LED. [18] However, we would expect such triplet interactions to produce long-lived singlet emission with a lifetime comparable to the lifetime of the triplet. No such emission was observed in our experiments. We therefore consider the bimolecular decay of triplets to be a relatively weak effect in our devices. In principle (iii), a small triplet cross-section value, could explain our data. The value, however, would have to be at least two orders of magnitude smaller than cross-sections found in other polymers to be consistent with singlet±triplet ratios found in other devices, which is highly unlikely. For this reason, we conclude that (i), a very small triplet formation probability, is the most likely explanation for the absence of a triplet absorption in our F8BT devices.To understand why triplet formation is strongly suppressed in F8BT compared to F8 and PPV, one can focus on the differing physical properties of singlet and triplet excitons arising from electron-correlation effects. As a carrier hops onto a chain harboring an oppositely charged carrier, the charges can recombine or migrate away from each other. As discussed recently, the exchange interaction between oppositely charged carriers is governed by the extent of the conjugation along the polymer backbone, and hence the chain rigidity. [5,6] The coulombic field is, however, mostly unaffected by the chain conformation. Consequently, spin-symmetric charges residing on opposite ends of a rigid polymer chain will have a larger exchange energy compared to a less rigid chain, and will thus favor formation of singlet excitons. We therefore speculate that the highly planar conformation expected of F8BT compared to F8 and PPV is responsible for the high singlet fraction found in the device. Hence, we propose that improvements in the planarity of the polymer backbone favor smaller triplet yields due to improved mediation of the exchange interaction.Absorptions due to triplet excitons generated in polyfluorene-based polymer LEDs have been measured and limits set on their formation efficiency. Although triplets were found in F8 LEDs, no evidence for triplets was found in F8BT homopolymer or blend devices. This null measurement suggests that exciton formation is not only spin-dependent in conjugated polymers, but is highly spin-dependent in F8BT. Our work therefore highlights dependence of the singlet±triplet ratio on polymer chemical structure, showing that triplet formation can be heavily suppressed and is not a necessary obstacle to high-efficiency device operation. As a consequence, more work needs to be done to assess the ultimate limits of polymer LED efficiency. ExperimentalThe PA spectroscopy technique used in this work has been described elsewh...

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Simultaneous determination of renal clinical analytes in serum using hydrolase- and oxidase-encapsulated optical array biosensors

Tsai

Doong

2004

Analytical Biochemistry

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Multifunctional Flow-injection Biosensor for the Simultaneous Measurement of Creatinine, Glucose, and Urea

Cited by 9 publications

References 1 publication

Development of a biparametric bioanalyser for creatinine and urea. Validation of the determination of biochemical parameters associated with hemodialysis

Development of a biparametric bioanalyser for creatinine and urea. Validation of the determination of biochemical parameters associated with hemodialysis

Conjugated Polymer Inverse Opals for Potentiometric Biosensing

Simultaneous determination of renal clinical analytes in serum using hydrolase- and oxidase-encapsulated optical array biosensors

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