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Detection of Nitric Oxide and Superoxide Radical Anion by Electron Paramagnetic Resonance Spectroscopy from Cells using Spin Traps
Published on: August 18, 2012
Choline oxidase as a selective recognition element for determination of paraoxon
Sharareh Sajjadi1, Hedayatollah Ghourchian, Hassan Tavakoli
1Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, Enghelab Street, Tehran, Iran.
Abstract:
A simple mono-enzyme biosensor has been developed for specific determination of paraoxon (POX). In this biosensor, choline oxidase (ChOx) was introduced and used as a new recognition element. Besides, by application of Prussian blue (PB), as an electron mediator, the necessity of applying oxygen or hydrogen peroxide sensor, as the internal transducer, was abated. The method was based on PB chemically modified screen-printed electrode coupled with ChOx for detection of POX as inhibitor. The concentration of H(2)O(2) produced by ChOx was electrochemically determined by the PB modified electrode at -50 mV versus the internal screen-printed Ag pseudo-reference electrode. The decrease in current caused by the addition of inhibitor was used for evaluation of POX concentration. The experimental parameters such as the quantity of enzyme, substrate concentration and incubation time were optimized for ChOx inhibition. At the incubation time of 5 min, the biosensor response was linear from 0.1 to 1 microM of POX with a detection limit of 0.1 microM.
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