Bioelectrocatalytic detection of theophylline at theophylline oxidase electrodes
(2007) In Biosensors & Bioelectronics 22(11). p.2508-2515- Abstract
- Bioelectrocatalytic oxidation of theophylline was studied at gold and graphite electrodes modified with microbial theophylline oxidase (ThOx), a multi-cofactor redox enzyme capable of selective oxidation of theophylline. Gold electrodes were additionally modified with self-assembled monolayers (SAMs) of (-OH)- and (-NH2)-terminated alkanethiols of different chain lengths, to achieve compatibility between ThOx and the electrode surface. On graphite, ThOx was either physically co-adsorbed with a surfactant didodecyldimethylammonium bromide (DDAB), or entrapped within an Os-redox-polymer film. At all electrodes, ThOx was bioelectrocatalytically active; direct electrochemistry of ThOx in the absence of theophylline was followed only at the... (More)
- Bioelectrocatalytic oxidation of theophylline was studied at gold and graphite electrodes modified with microbial theophylline oxidase (ThOx), a multi-cofactor redox enzyme capable of selective oxidation of theophylline. Gold electrodes were additionally modified with self-assembled monolayers (SAMs) of (-OH)- and (-NH2)-terminated alkanethiols of different chain lengths, to achieve compatibility between ThOx and the electrode surface. On graphite, ThOx was either physically co-adsorbed with a surfactant didodecyldimethylammonium bromide (DDAB), or entrapped within an Os-redox-polymer film. At all electrodes, ThOx was bioelectrocatalytically active; direct electrochemistry of ThOx in the absence of theophylline was followed only at the SAM-modified gold electrodes. Direct electrochemistry of ThOx correlated with redox transformations of the heme domain of ThOx, with a E-o/ of - 110 +/- 2 mV versus Ag vertical bar AgCl, at pH 7. Bioelectrocatalytic oxidation of theophylline was optimal at mixed (-OH)/(-NH2)-terminated SAMs; co-adsorption of ThOx with DDAB improved the bioelectrocatalytic performance of the ThOx-electrode. In both cases, the response to theophylline was within the mM range. Alternatively, a reagentless ThOx-electrode based on ThOx cross-linked within the Os-redox-polymer matrix demonstrated a linear response to theophylline within the physiologically important 0.02-0.6 mM (3.6-72 mg I-1) concentration range with a sensitivity of 52.1 +/- 7.8 mA cm(-2) m(-1). (c) 2006 Elsevier B.V. All rights reserved. (Less)
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- author
- Ferapontova, Elena E. ; Shipovskov, Stepan and Gorton, Lo LU
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- graphite, gold, alkanethiols, theophylline oxidase, bioelectrocatalysis, osmium-complex redox polymer
- in
- Biosensors & Bioelectronics
- volume
- 22
- issue
- 11
- pages
- 2508 - 2515
- publisher
- Elsevier
- external identifiers
-
- wos:000246382500017
- scopus:33947596231
- ISSN
- 1873-4235
- DOI
- 10.1016/j.bios.2006.09.034
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Analytical Chemistry (S/LTH) (011001004)
- id
- 3093a750-285e-4254-8f5e-0ec7120df3a9 (old id 660586)
- date added to LUP
- 2016-04-01 15:24:49
- date last changed
- 2022-01-28 05:10:46
@article{3093a750-285e-4254-8f5e-0ec7120df3a9,
abstract = {{Bioelectrocatalytic oxidation of theophylline was studied at gold and graphite electrodes modified with microbial theophylline oxidase (ThOx), a multi-cofactor redox enzyme capable of selective oxidation of theophylline. Gold electrodes were additionally modified with self-assembled monolayers (SAMs) of (-OH)- and (-NH2)-terminated alkanethiols of different chain lengths, to achieve compatibility between ThOx and the electrode surface. On graphite, ThOx was either physically co-adsorbed with a surfactant didodecyldimethylammonium bromide (DDAB), or entrapped within an Os-redox-polymer film. At all electrodes, ThOx was bioelectrocatalytically active; direct electrochemistry of ThOx in the absence of theophylline was followed only at the SAM-modified gold electrodes. Direct electrochemistry of ThOx correlated with redox transformations of the heme domain of ThOx, with a E-o/ of - 110 +/- 2 mV versus Ag vertical bar AgCl, at pH 7. Bioelectrocatalytic oxidation of theophylline was optimal at mixed (-OH)/(-NH2)-terminated SAMs; co-adsorption of ThOx with DDAB improved the bioelectrocatalytic performance of the ThOx-electrode. In both cases, the response to theophylline was within the mM range. Alternatively, a reagentless ThOx-electrode based on ThOx cross-linked within the Os-redox-polymer matrix demonstrated a linear response to theophylline within the physiologically important 0.02-0.6 mM (3.6-72 mg I-1) concentration range with a sensitivity of 52.1 +/- 7.8 mA cm(-2) m(-1). (c) 2006 Elsevier B.V. All rights reserved.}},
author = {{Ferapontova, Elena E. and Shipovskov, Stepan and Gorton, Lo}},
issn = {{1873-4235}},
keywords = {{graphite; gold; alkanethiols; theophylline oxidase; bioelectrocatalysis; osmium-complex redox polymer}},
language = {{eng}},
number = {{11}},
pages = {{2508--2515}},
publisher = {{Elsevier}},
series = {{Biosensors & Bioelectronics}},
title = {{Bioelectrocatalytic detection of theophylline at theophylline oxidase electrodes}},
url = {{http://dx.doi.org/10.1016/j.bios.2006.09.034}},
doi = {{10.1016/j.bios.2006.09.034}},
volume = {{22}},
year = {{2007}},
}