Ultrathin Porous Carbon Films as Amperometric Transducers for Biocatalytic Sensors

Wang, Joseph.; Chen, Qiang; Renschler, Clifford L.; White, Christine

doi:10.1021/ac00085a011

Cited by 44 publications

(33 citation statements)

References 9 publications

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“…1, top) shows that the integrity of the Teflon-metal seal was not compromised significantly by the cutting procedure used to form the bare disc from the wire. Interesting aspects of the surface structure of PPD formed from the different isomers of phenylenediamine [27][28][29][30] and other electro-deposited polymers [31][32][33] have been revealed in the past by scanning electron microscopy. Crater-like features described previously for PPD formed on metal cylinders from the ortho monomer [27,30] were also evident at higher magnifications for PPD electro-deposited onto the Pt D electrode ( Fig.…”

Section: Scanning Electron Microscopymentioning

confidence: 99%

Highly selective and stable microdisc biosensors for l-glutamate monitoring

Govindarajan

McNeil

Lowry

et al. 2013

Sensors and Actuators B: Chemical

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a b s t r a c tGlutamate mediates most of the excitatory synaptic transmission in the brain, and its abnormal regulation is considered a key factor underlying the appearance and progression of many neurodegenerative and psychiatric diseases. In this work, a microdisc-based amperometric biosensor for glutamate detection with highly enhanced selectivity and good stability is proposed. The biosensor utilizes the enzyme glutamate oxidase which was dip-coated onto 125 m diameter platinum discs. To improve selectivity, phosphatidylethanolamine was pre-coated prior to enzyme deposition, and electropolymerization of o-phenylenediamine was performed to entrap the enzyme within a polymer matrix. A variety of coating configurations were tested in order to optimize biosensor performance. For stability measurements, biosensors were biased continuously and calibration curves calculated each day for a period of 5-6 days. The optimized biosensors exhibited very high sensitivity (71 ± 1 mA M −1 cm −2 ), low detection limit of ∼2.5 M glutamate, selectivity (over 87% against ascorbic acid), very good temporal stability during continuous use, and a response time of <5 s. These biosensors are therefore good candidates for further development as devices for continuous monitoring during traumatic brain injury or neurosurgery.

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Section: Scanning Electron Microscopymentioning

confidence: 99%

Highly selective and stable microdisc biosensors for l-glutamate monitoring

Govindarajan

McNeil

Lowry

et al. 2013

Sensors and Actuators B: Chemical

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“…17,78,81,85 Thus, the compromised structure of PPD deposited at the insulation edge, indicated by the analysis for P(AA)% above, would not be anticipated to impact on P(H 2 O 2 )% values already close to those for the bare metal. We await the commissioning of a scanning electrochemical microscope to probe the structure of the PPD-edge interface; scanning electron microscopy, which has revealed interesting aspects of PPD structure in the past, 50,56,95 tends to "burn" organic polymer deposits at the high magnifications needed to study this level of detail.…”

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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“…[1][2][3][4][5][6][7] Although numerous methods such as chemical vapor deposition, hydrothermal decomposition of carbide compounds, and polymer coating and pyrolysis have been developed for the fabrication of carbon film, [8][9][10] easily scalable self-supported nanoporous carbon films have not yet been obtained with any of them. The following promising methods for fabricating the pore structure of carbon film have recently been reported: colloidal silica imprinting, microbead patterning, and presynthesized mesoporous silica scaffolding.…”

mentioning

confidence: 99%

High capacitance carbon-based xerogel film produced without critical drying

Tao

Endo

Ohsawa

et al. 2008

Applied Physics Letters

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We report the production of carbon-based xerogel film without the need for supercritical drying. Xerogel samples were characterized with field emission scanning electron microscopy, nitrogen adsorption/desorption at 77 K, Raman spectroscopy, thermogravimetric analysis, and electrical conductivity and cyclic voltammetry measurements. Experimental results reveal that the film is largely crack free and homogeneous in thickness, and, importantly, has high surface area, large nanopore volume, and an excellent performance for electrical charge storage-both per unit mass and unit volume. These results indicate that the film has potential applications for electrical energy storage devices.

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Ultrathin Porous Carbon Films as Amperometric Transducers for Biocatalytic Sensors

Cited by 44 publications

References 9 publications

Highly selective and stable microdisc biosensors for l-glutamate monitoring

Highly selective and stable microdisc biosensors for l-glutamate monitoring

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

High capacitance carbon-based xerogel film produced without critical drying

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