Methylene blue covalently attached to single stranded DNA as electroactive label for potential bioassays

Methylene blue is an electroactive molecule that has been employed for the detection of the DNA hybridization event in electrochemical sensors. However, its use as a covalent label is very scarce and in most of the cases, non-covalent interactions (hydrophobic, electrostatic) are employed. Although...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2014-02, Vol.191, p.784-790
Main Authors: García-González, Raquel, Costa-García, Agustín, Fernández-Abedul, M. Teresa
Format: Article
Language:English
Subjects:
Actuators
Attachment
Carbon nanotubes
Covalence
Covalent electroactive labels
Deoxyribonucleic acid
Electrodes
Genosensors
Labels
Methylene blue
Nanostructured electrodes
Screen-printed gold electrodes
Sensors
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Summary:Methylene blue is an electroactive molecule that has been employed for the detection of the DNA hybridization event in electrochemical sensors. However, its use as a covalent label is very scarce and in most of the cases, non-covalent interactions (hydrophobic, electrostatic) are employed. Although it has advantages as simplicity and fewer number of procedure steps, the covalent attachment is less exploited in the development of these sensors. In this article, the electrochemical behavior of methylene blue attached to different DNA-strands is studied. Several lengths (15- and 30-mer) and different degree of DNA modification (MB-DNA, MB-DNA-MB and MB-DNA-SH) have been studied. The highest signals were obtained for longer strands with two MB molecules. In all the cases the signal is enhanced by CNT-nanostructuration of the electrode. Adsorption on these modified screen-printed electrodes allowed the amplification by employing an accumulation time. In this way, a sensitivity of −0.2864μAμM−1 and a limit of detection of 800nM for a 120s accumulation time were obtained.
ISSN:0925-4005
1873-3077
0925-4005
DOI:10.1016/j.snb.2013.10.037