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Morrin A, Wilbeer F, Ngamna O, Moulton SE, Killard AJ, Wallace GG, Smyth MR. Novel biosensor fabrication methodology based on processable conducting polyaniline nanoparticles. Electrochem commun 2005. [DOI: 10.1016/j.elecom.2005.01.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Morrin A, Moutloali R, Killard A, Smyth M, Darkwa J, Iwuoha E. Organic Phase Cyclopentadienylnickelthiolate Sensor System for Electrochemical Determination of Sulfur Dioxide. ELECTROANAL 2004. [DOI: 10.1002/elan.200403052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Iwuoha EI, Williams-Dottin AR, Hall LA, Morrin A, Mathebe GN, Smyth MR, Killard A. Electrochemistry and application of a novel monosubstituted squarate electron-transfer mediator in a glucose oxidase-doped poly(phenol) sensor. PURE APPL CHEM 2004. [DOI: 10.1351/pac200476040789] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Electrosynthetic poly(phenol) nanofilms were deposited in situ on platinum electrodes in the presence and absence of glucose oxidase. The synthesis charges and currents of the nonconducting polymer films were recorded at various applied potentials for films grown from 25 –100 mM phenol concentrations. Film parameters such as the standard rate constant for film deposition, film thickness, and surface concentration of the poly(phenol) films were evaluated from the cyclic and step voltammograms of the polymerization process. A novel electron-transfer mediator consisting of monosubstituted 4-hydroxycyclobut-3-ene-1,2-dione (squarate) was used as a mediator for Pt/poly(phenol) nanofilm/GOx amperometric glucose biosensors. Amperometric responses for 3-diphenylamino-4-hydroxycyclobut-3-ene-1,2-dione (diphenylaminosquarate: E°'=of +328 mV/Ag-AgCl at pH 7.0)-mediated systems were measured by both steady-state amperometric and cyclic voltammetry. The sensor sensitivity was calculated to be 558 nA cm−2 (µM)−1.
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Affiliation(s)
- E. I. Iwuoha
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - A. R. Williams-Dottin
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - L. A. Hall
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - A. Morrin
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - G. N. Mathebe
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - M. R. Smyth
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - Anthony Killard
- 1Department of Chemistry, University of the Western Cape, Belleville 7535, South Africa; Department of Chemistry, The University of the West Indies, St.Augustine, Trinidad; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
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Morrin A, Guzman A, Killard AJ, Pingarron JM, Smyth MR. Characterisation of horseradish peroxidase immobilisation on an electrochemical biosensor by colorimetric and amperometric techniques. Biosens Bioelectron 2003; 18:715-20. [PMID: 12706583 DOI: 10.1016/s0956-5663(03)00003-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study presents the use of complementary colorimetric and amperometric techniques to measure the quantity of protein or enzyme immobilised onto a carbon paste electrode modified with a layer of electrodeposited polyaniline. By applying a solution of bovine serum albumin at 0.75 mg/ml, efficient blocking of the electrode from electroactive species in the bulk solution could be achieved. When the horseradish peroxidase was immobilised on the electrode, optimal amperometric responses from hydrogen peroxide reduction were achieved at approximately the same concentration. The mass of enzyme immobilised at this solution concentration was determined by a colorimetric enzyme assay to be equivalent to the formation of a protein monolayer. Under these conditions, amperometric responses from the immobilised layer are maximised and non-specific bulk solution interactions are minimised. At higher immobilised protein concentrations, diminished amperometric responses may be due to inhibited diffusion of hydrogen peroxide to enzyme which is in electronic communication with the electrode surface, or impeded electron transfer.
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Affiliation(s)
- Aoife Morrin
- School of Chemical Sciences, Dublin City University, 9, Dublin, Ireland
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