Evaluation of osmium(II) complexes as mediators accessible for biosensors

Nakabayashi, Yasuo; Omayu, Atsushi; Morii, Sonoko; Yagi, Shiro

doi:10.1016/s0925-4005(00)00324-5

Cited by 14 publications

(16 citation statements)

References 8 publications

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“…Also, ruthenium purple-zeolite-modified electrodes have lately been tested [8], and the solution of Ru (NH 3 ) 3+ 6 has been employed in a 'capillary fill device' [22]. Moreover, the use of Os(II) complexes, applied earlier for 'enzyme wiring' [23], has been recently studied [24] and reviewed [25].…”

Section: Edyta Kosela · Hanna Elzanowska · Wlodzimierz Kutnermentioning

confidence: 99%

Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated β-cyclodextrin polymer membranes

2002

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Four different poly(pyridine) complexes of ruthenium, viz. Ru(II)(trpy)(phen)(OH(2))](2+) (1), trans-[Ru(III)(2,2'bpy)(2)(OH(2))(OH)](2+) (2), [(2,2'bpy)(2)(OH)Ru(III)ORu(III)(OH)(2,2'bpy)(2)](4+) (3), and [Ru(II)(4,4'bpy)(NH(3))(5)](2+) (4) (2,2'bpy=2,2'-bipyridine, 4,4'bpy=4,4'-bipyridine, trpy=2,2',2"-terpyridine, phen=1,10-phenanthroline), were tested as non-physiological charge mediators of 'second-generation' glucose biosensors. The membranes for these biosensors were prepared by casting anionic carboxymethylated beta-cyclodextrin polymer films (beta-CDPA) directly onto the Pt or glassy carbon (GC) disk electrodes. Simultaneously, glucose oxidase (GOD) was immobilized in the films by covalent bonding and the Ru complexes were incorporated both by inclusion in the beta-CD molecular cavities and by ion exchange at the fixed carboxymethyl cation-exchange sites. The leakage of the mediator from the polymer has been minimized by adopting a suitable pre-treatment procedure. The biosensors catalytic activities increased in the order 1<2<3<4, as established by linear sweep voltammetry. In case of complexes 2-4, the enzymatic glucose oxidation was mediated by the Ru complexes at their redox potentials. However, this oxidation was mediated by oxygen in case of complex 1 where H(2)O(2) was detected as the reaction product. The effectiveness of the mediators used in the presence of oxygen has been estimated using Pt and GC supports. The redox potential of the mediator does not depend on the support used, while the oxidation of H(2)O(2) proceeds on GC at much higher positive potentials than on Pt. The sensitivity and the linear concentration range of the biosensor studied varied significantly. For complex 4, which forms stable inclusion complex with beta-CD, the biosensor sensitivity was the highest and equal to 7.2 micro A mM(-1) cm(-2), detectability was as low as 1 mM, but the linear concentration range was limited only to 4 mM. In contrast, for complexes 2 and 3 the sensitivity was 0.4 and 3.2 micro A mM(-1) cm(-2), while the linear concentration range extended up to at least 24 and 14 mM glucose, respectively. Even though some common interfering substances, such as ascorbate, paracetamol or urea, are oxidized at potentials close to those of the Ru complex redox couples, their electro-oxidation currents at physiological concentrations are insignificant compared to those due to the biocatalytic oxidation of glucose. The biosensor response to glucose is reversible as demonstrated by the inhibition of GOD activity by Cu(II). That is, the Cu(II) concentration required to inhibit by half the response to glucose of the biosensor containing complex 2 was 1.0 mM. This inhibitory effect was fully reversed by addition of citrate, a ligand forming sufficiently stable complex with Cu(II).

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Section: Edyta Kosela · Hanna Elzanowska · Wlodzimierz Kutnermentioning

confidence: 99%

Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated β-cyclodextrin polymer membranes

2002

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“…Mediator based enzymatic electrodes are the most widely reported in literature [4,12,13]. These devices are based on the use of redox mediators, low molecular weight substances able to realize a fast electron transfer from the enzyme redox center to the working electrode surface and vice versa.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Kinetic Characterization of Redox Mediated Glucose Oxidase Reactions: A Simplified Approach

Noci¹,

Frasconi²,

Favero³

et al. 2008

Electroanalysis

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One of the main drawbacks affecting first-generation electrochemical biosensors in the analysis of real matrices is the interference of electroactive species present in the sample under investigation. Several approaches have been attempted to overcome this problem in the past ten years but the best results were achieved by using mediated based electrochemical biosensors. Despite this, the kinetic of the redox mediators-enzymatic proteins interaction has not been studied deeply enough. In this work we have developed a theoretical-methodological approach for the characterization of the kinetic of interaction between redox enzymes and substrates and/or redox mediators. Particularly, the interaction of glucose oxidase (GOx) with several commercially available redox mediators has been studied by means of amperometry and cyclic voltammetry. The main kinetic parameters for different mediators were exploited and discussed with the aim of finding the best mediator for a glucose biosensor to be used on real samples.

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“…Biosensors based on ferrocene derivatives [3][4][5] , quinone derivatives 6,7 , organic conducting salts such as TTF-TCNQ 8,9 and on osmium(II) complexes 10 have been reported.…”

Section: Introductionmentioning

confidence: 99%

Glucose Amperometric Biosensor Based on the Co-immobilization of Glucose Oxidase (GOx) and Ferrocene in Poly(pyrrole) Generated from Ethanol / Water Mixtures

Fiorito¹,

Torresi²

2001

J. Braz. Chem. Soc.

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Neste trabalho é apresentada a co-imobilização de GOx e ferroceno numa matriz polimérica através de um método simples de uma etapa. Esse procedimento para a imobilização de ferroceno como mediador da reação enzimática não envolve a modificação do monômero ou da enzima, o que poderia levar à perda de sua atividade. A incorporação de ferroceno se traduz no incremento da sensibilidade, comparado ao sensor sem mediador redox (1,5 vs 0,23 µA mmol -1 L cm -2 ) e diminuição do potencial de trabalho até 0,4 V. O sensor desenvolvido mostra resposta linear até 10 mmol L -1 e um tempo de resposta de 2 s, além de razoável estabilidade depois de uma semana de uso.The co-immobilization of GOx and ferrocene in a polymeric matrix by a one-step simple method is presented. This procedure to immobilize ferrocene as mediator implies the absence of modification of the monomer or the enzyme that would lead to the loss of its activity. Ferrocene incorporation results in an increase of sensitivity compared with the sensor prepared without the redox mediator (1.5 vs 0.23 µA mmol -1 L cm -2 ) and the decrease of the working potential to 0.4 V. The prepared sensor shows linear response till 10 mmol L -1 and response time of 2 s, in addition to reasonable stability after one week.

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Evaluation of osmium(II) complexes as mediators accessible for biosensors

Cited by 14 publications

References 8 publications

Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated β-cyclodextrin polymer membranes

Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated β-cyclodextrin polymer membranes

Electrochemical Kinetic Characterization of Redox Mediated Glucose Oxidase Reactions: A Simplified Approach

Glucose Amperometric Biosensor Based on the Co-immobilization of Glucose Oxidase (GOx) and Ferrocene in Poly(pyrrole) Generated from Ethanol / Water Mixtures

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