TITLE

Bioanalytical device based on cholesterol oxidase-bonded SAM-modified electrodes

AUTHOR(S)
Parra, A.; Casero, E.; Pariente, F.; Vázquez, L.; Lorenzo, E.
PUB. DATE
July 2007
SOURCE
Analytical & Bioanalytical Chemistry;Jul2007, Vol. 388 Issue 5/6, p1059
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A rapid, simple and reproducible two-step method for constructing cholesterol biosensors by covalently bonding cholesterol oxidase (ChOx) to a 3,3′-dithiodipropionic acid di( N-succinimidyl ester) (DTSP)-modified gold electrode is described. Exhaustive characterizations of both the immobilization process and the morphological properties of the resulting ChOx monolayer were performed via a quartz crystal microbalance (QCM) and atomic force microscopy (AFM) operated under liquid conditions, respectively. In addition, scanning electrochemical microscopy (SECM) measurements were performed in order to check that the immobilized enzyme retains its catalytic activity. The replacement of the natural electron acceptor (O2) in the enzymatic reaction with an artificial mediator, hydroxymethylferrocene (HMF), was also studied. Finally, cholesterol was amperometrically determined by measuring the hydrogen peroxide produced during the enzymatic reaction at +0.5 V. The optimized cholesterol biosensor exhibited a sensitivity of 54 nA mM−1 and a detection limit of 22 μM.
ACCESSION #
25603354

 

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