Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops
The activity of a peroxidase-mimicking DNAzyme was optimized to be used as a catalytic label in a stem-loop genosensor construction for quantifying the gene sequence Shiga-like toxin I of verotoxigenic E. coli. Experimental conditions such as pH, buffer composition, potassium ion concentration, and...
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doaj-3e7aa34a46cf406e8ebe7026eea4afbe2020-11-25T03:27:44ZengInternational Association of Physical Chemists (IAPC)Journal of Electrochemical Science and Engineering1847-92862017-12-017410.5599/jese.471276Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loopsGloria Longinotti0Gabriel Ybarra1Javier Montserrat21U.T. Nanomateriales, INTI-Procesos Superficiales, Instituto Nacional de Tecnología Industrial (INTI), Av. Gral. Paz 5445, B1650WAB San MartínU.T. Nanomateriales, INTI-Procesos Superficiales, Instituto Nacional de Tecnología Industrial (INTI), Av. Gral. Paz 5445, B1650WAB San MartínUniversidad Nacional de General Sarmiento, J. M. Gutiérrez 1150, B1613GSX, Los Polvorines, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)The activity of a peroxidase-mimicking DNAzyme was optimized to be used as a catalytic label in a stem-loop genosensor construction for quantifying the gene sequence Shiga-like toxin I of verotoxigenic E. coli. Experimental conditions such as pH, buffer composition, potassium ion concentration, and hemin-to-oligonucleotides ratio, were analyzed to maximize optical and electrochemical responses using microvolumes. Different stem-loop constructions were evaluated to obtain the optimum response against the target concentration. Linear ranges of 0.05-0.5 µM and limits of detection of 174 nM and 144 nM were estimated for the optical and electrochemical measurements, respectively. Selectivity was proved by assaying other verotoxigenic, enterotoxigenic and enteroinvasive sequences. The results show that, if a combination of small-volume electrochemical cells and low-cost untreated screen-printed electrodes with a relatively high geometric area is used, electrochemical measurements present similar sensitivity and limits of detection to the more usual optical ones, allowing the development of low-cost electrochemical biosensors based on the use of soluble DNAzymes as labels. http://pub.iapchem.org/ojs/index.php/JESE/article/view/471BiosensorsGenosensorsDNAzyme PeroxidaseVerotoxigenic E. coli |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Gloria Longinotti Gabriel Ybarra Javier Montserrat |
spellingShingle |
Gloria Longinotti Gabriel Ybarra Javier Montserrat Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops Journal of Electrochemical Science and Engineering Biosensors Genosensors DNAzyme Peroxidase Verotoxigenic E. coli |
author_facet |
Gloria Longinotti Gabriel Ybarra Javier Montserrat |
author_sort |
Gloria Longinotti |
title |
Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops |
title_short |
Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops |
title_full |
Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops |
title_fullStr |
Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops |
title_full_unstemmed |
Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops |
title_sort |
optical and electrochemical detection of a verotoxigenic e. coli gene using dnazyme-labeled stem-loops |
publisher |
International Association of Physical Chemists (IAPC) |
series |
Journal of Electrochemical Science and Engineering |
issn |
1847-9286 |
publishDate |
2017-12-01 |
description |
The activity of a peroxidase-mimicking DNAzyme was optimized to be used as a catalytic label in a stem-loop genosensor construction for quantifying the gene sequence Shiga-like toxin I of verotoxigenic E. coli. Experimental conditions such as pH, buffer composition, potassium ion concentration, and hemin-to-oligonucleotides ratio, were analyzed to maximize optical and electrochemical responses using microvolumes. Different stem-loop constructions were evaluated to obtain the optimum response against the target concentration. Linear ranges of 0.05-0.5 µM and limits of detection of 174 nM and 144 nM were estimated for the optical and electrochemical measurements, respectively. Selectivity was proved by assaying other verotoxigenic, enterotoxigenic and enteroinvasive sequences. The results show that, if a combination of small-volume electrochemical cells and low-cost untreated screen-printed electrodes with a relatively high geometric area is used, electrochemical measurements present similar sensitivity and limits of detection to the more usual optical ones, allowing the development of low-cost electrochemical biosensors based on the use of soluble DNAzymes as labels.
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topic |
Biosensors Genosensors DNAzyme Peroxidase Verotoxigenic E. coli |
url |
http://pub.iapchem.org/ojs/index.php/JESE/article/view/471 |
work_keys_str_mv |
AT glorialonginotti opticalandelectrochemicaldetectionofaverotoxigenicecoligeneusingdnazymelabeledstemloops AT gabrielybarra opticalandelectrochemicaldetectionofaverotoxigenicecoligeneusingdnazymelabeledstemloops AT javiermontserrat opticalandelectrochemicaldetectionofaverotoxigenicecoligeneusingdnazymelabeledstemloops |
_version_ |
1724587398516441088 |