Poly(o-phenylenediamine) ultra-thin polymer-film composite membranes for enzyme electrodes

Myler, Suzy; Eaton, Sarah Elaine; Higson, Séamus P.J.

doi:10.1016/s0003-2670(97)00558-8

Cited by 72 publications

(104 citation statements)

References 11 publications

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“…Pt F /PEI/GluOx/PPD biosensors, incorporating the enzyme GluOx and sensitivity-boosting polycation PEI, 31,42,46,96 were therefore fabricated and calibrated in vitro for Glu, H 2 O 2 , and AA. The sensitivity to Glu in the linear response region of the Michaelis-Menten calibration curve was high (62 ± 8 µA cm -2 mM -1 , n ) 14), representing 24 ± 4% of the sensitivity of the same biosensors in H 2 O 2 calibrations performed under the same quiescent conditions, and reflecting efficient enzyme kinetics in these ultrathin insulating PPD coatings (<30 nm [56][57][58][59][60] 14%, n ) 14) and P(AA)% (0.20 ± 0.04%, n ) 14) indicate that the dip-evaporation deposition of both PEI and GluOx on the bare Pt F before PPD electrosynthesis only marginally affected the ability of the composite polymer matrix to reject AA interference or to enable efficient H 2 O 2 transport to the metal surface. Not surprisingly, as a result of incorporating these two macromolecular species into the PPD matrix, its permeability increased, but by only a factor of 2 for both parameters (see Figures 4 and 5), minimizing the effects on selectivity.…”

Section: P(aa)% Analysis For Ppd-modified Electrodesmentioning

confidence: 99%

Contributions by a Novel Edge Effect to the Permselectivity of an Electrosynthesized Polymer for Microbiosensor Applications

et al. 2009

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Pt electrodes of different sizes (2 × 10 -5 -2 × 10 -2 cm 2 ) and geometries (disks and cylinders) were coated with the ultrathin non-conducting form of poly(o-phenylenediamine), PPD, using amperometric electrosynthesis. Analysis of the ascorbic acid (AA) and H 2 O 2 apparent permeabilities for these Pt/PPD sensors revealed that the PPD deposited near the electrode insulation (Teflon or glass edge) was not as effective as the bulk surface PPD for blocking AA access to the Pt substrate. This discovery impacts on the design of implantable biosensors where electrodeposited polymers, such as PPD, are commonly used as the permselective barrier to block electroactive interference by reducing agents present in the target medium. The undesirable "edge effect" was particularly marked for small disk electrodes which have a high edge density (ratio of PPDinsulation edge length to electrode area), but was essentially absent for cylinder electrodes with a length of >0.2 mm. Sample biosensors, with a configuration based on these findings (25 µm diameter Pt fiber cylinders) and designed for brain neurotransmitter L-glutamate, behaved well in vitro in terms of Glu sensitivity and AA blocking.The design of biosensors for implantation in functioning biological tissues is an important area of research with significant socioeconomic impact. 1-4 Depending on the target analyte, different signal transduction pathways have been exploited in the design of enzyme-based biosensors, including direct oxidation of reduced oxidases, 5-7 dehydrogenase chemistries, 8-10 redox mediators, 11-13 and spectrophotometric approaches. 14-16 However, "first generation" electrochemical biosensors, based on reactions 1-3, remain the most common design for many applications. 1,2,[17][18][19] The majority of these are oxidase-based devices designed to operate in amperometric mode, detecting H 2 O 2 generated by the reaction of the co-substrate (dioxygen) with the reduced form of the enzyme.First-generation biosensors in general, and especially those designed for tissue implantation, 20-24 must be capable of effective rejection of electroactive interference by endogenous reducing agents in the target medium because these devices are normally operated at a high applied overpotential for efficient H 2 O 2 * To whom correspondence should be addressed. E-mail: robert.oneill@ucd.ie.

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Section: P(aa)% Analysis For Ppd-modified Electrodesmentioning

confidence: 99%

Contributions by a Novel Edge Effect to the Permselectivity of an Electrosynthesized Polymer for Microbiosensor Applications

et al. 2009

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“…However, a recent study has shown that substrate diffusion is not limiting for PPD layers incorporating enzyme (De Corcuera et al, 2005), due to their relatively small thickness (Gooding et al, 1998). Therefore, the basic Michaelis-Menten enzyme parameters used here provide more readily accessible insights into factors affecting the responsiveness of biosensors fabricated from ultra-thin (10-30 nm; Malitesta et al, 1990;Sohn et al, 1991;Myler et al, 1997;Craig and O'Neill, 2003) insulating PPD, and avoids the use of more complex analyses, such as those involving the Thiele modulus (Gooding and Hall, 1996).…”

Section: Kinetic Model and Data Analysismentioning

confidence: 99%

Oxygen tolerance of an implantable polymer/enzyme composite glutamate biosensor displaying polycation-enhanced substrate sensitivity

McMahon¹,

Rocchitta²,

Kirwan³

et al. 2007

Biosensors and Bioelectronics

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Biosensors were fabricated at neutral pH by sequentially depositing the polycation polyethyleneimine (PEI), the stereoselective enzyme l-glutamate oxidase (GluOx) and the permselective barrier poly-ortho-phenylenediamine (PPD) onto 125-m diameter Pt wire electrodes (Pt/PEI/GluOx/PPD). These devices were calibrated amperometrically at 0.7 V versus SCE to determine the Michaelis-Menten parameters for enzyme substrate, l-glutamate (Glu) and co-substrate, dioxygen. The presence of PEI produced a 10-fold enhancement in the detection limit for Glu (∼20 nM) compared with the corresponding PEI-free configurations (Pt/GluOx/PPD), without undermining their fast response time (∼2 s). Most remarkable was the finding that, although some designs of PEI-containing biosensors showed a 10-fold increase in linear region sensitivity to Glu, their oxygen dependence remained low.

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“…Many of these polymer electrodes have been discussed from the viewpoint of potential response mechanism, lower detection limit, and selectivity coefficient [1][2][3][4]. Polymer membranes have also been used as a matrix in enzyme electrode [5][6][7]. But in the majority of cases, they have been used in water solution.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical characterization of poly(acrylamide) membrane coated on a gold disk electrode in acetonitrile

Ji¹,

Jin²,

Ren³

et al. 2005

Journal of Electroanalytical Chemistry

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The electrochemical behavior of a poly(acrylamide) (PAA) membrane electrode (ME), in which the PAA works as a membrane matrix for use in nonaqueous solutions, was investigated in acetonitrile. It was found that PAA MEs possess properties of microelectrode ensembles (MEEs).For the thin PAA membrane, the electrode behaved similar to a macroelectrode and peak-shaped voltammograms were achieved at low scan rates, while at high scan rates the electrode acted as a microelectrode and sigmoidal-shaped voltammograms were obtained. For the thick PAA membrane electrode, however, voltammograms were sigmoidal-shaped at low scan rates, and at high scan rates the voltammograms became peak-shaped again. Quantitative and semiquantitative analyses of the electrochemical response characteristics of these ensembles were conducted. The results show that the electrochemical behavior of these ensembles is in close agreement with the predictions of established microwell electrochemical theory.

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Poly(o-phenylenediamine) ultra-thin polymer-film composite membranes for enzyme electrodes

Cited by 72 publications

References 11 publications

Contributions by a Novel Edge Effect to the Permselectivity of an Electrosynthesized Polymer for Microbiosensor Applications

Contributions by a Novel Edge Effect to the Permselectivity of an Electrosynthesized Polymer for Microbiosensor Applications

Oxygen tolerance of an implantable polymer/enzyme composite glutamate biosensor displaying polycation-enhanced substrate sensitivity

Electrochemical characterization of poly(acrylamide) membrane coated on a gold disk electrode in acetonitrile

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