Characterization of permselective coatings electrosynthesized on Pt–Ir from the three phenylenediamine isomers for biosensor applications

Killoran, Sarah J.; O’Neill, Robert

doi:10.1016/j.electacta.2008.03.076

Cited by 77 publications

(121 citation statements)

References 90 publications

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“…There was no statistically significant trend in the P(H 2 O 2 )% data over the entire range of fiber lengths (linear regression R 2 ) 0.03). This is in line with expectation, because the high H 2 O 2 permeability in PPD is one of its outstanding qualities which makes this polymer (both ortho and meta forms) 56,83,94 the permselective membrane of choice in many first-generation biosensor designs. 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.…”

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

confidence: 87%

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 Electrodessupporting

confidence: 87%

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

et al. 2009

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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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“…PPD modified Pt electrodes are extensively utilised to improve selectivity of the polymer layer of both electrochemical sensors [6,17,[22][23][24] and biosensors [11,[25][26][27][28] since extracellular concentrations of certain metabolites are considered low in relation to the excessive concentration of AA. Therefore it is imperative that the integrity of the polymer is retained following implantation.…”

Section: Shelf-life Studies-effect Of Repeated Aa Calibrationsmentioning

confidence: 99%

Ascorbic Acid Rejection Characteristics of Modified Platinum Electrodes: A Shelf Life Investigation

Wynne

Finnerty

2015

Chemosensors

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Ascorbic acid (AA) is the principle interferent present in brain extracellular fluid that can inhibit the ability of electrochemical sensors to selectively detect a particular analyte of interest. Considerable efforts have been made in recent times to develop highly selective membrane coatings to counteract the drawbacks associated with AA interference during in vivo monitoring. The primary objective of the work described within was to investigate the long term effect of storing such selective membranes, i.e., Nafion ® andPoly-o-phenylenediamine (PPD) under different conditions and how exposing them to repeated calibration protocols compromises the membranes ability to reject AA. Four different modified platinum (Pt) electrodes, Pt-PPD, Pt-Nafion ® (5/2), Pt-Nafion ® (1/2)-PPD, and Pt-Nafion ® (2/1)-PPD, stored at 4 °C demonstrated deterioration of the polymers integrity when exposed to repeated calibrations. On the contrary, exposing the same four electrode types to single calibrations confirmed excellent retention of AA rejection characteristics. Pt-PPD electrodes were then exposed to varying storage conditions and calibrated against AA on day 1, day 56 and day 168. Storing the Pt-PPD electrodes at 4 °C/N2 saturated glass container demonstrated retention of AA rejection characteristics after day 168. These results have clearly elucidated the optimum storage conditions for Pt-Nafion ® and Pt-PPD modified electrodes.

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Characterization of permselective coatings electrosynthesized on Pt–Ir from the three phenylenediamine isomers for biosensor applications

Cited by 77 publications

References 90 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

Highly selective and stable microdisc biosensors for l-glutamate monitoring

Ascorbic Acid Rejection Characteristics of Modified Platinum Electrodes: A Shelf Life Investigation

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