Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7232443 | Biosensors and Bioelectronics | 2015 | 7 Pages |
Abstract
Current EU regulations on the mandatory labeling of genetically modified organisms (GMOs) with a minimum content of 0.9% would benefit from the availability of reliable and rapid methods to detect and quantify DNA sequences specific for GMOs. Different genosensors have been developed to this aim, mainly intended for GMO screening. A remaining challenge, however, is the development of genosensing platforms for GMO quantification, which should be expressed as the number of event-specific DNA sequences per taxon-specific sequences. Here we report a simple and sensitive multiplexed electrochemical approach for the quantification of Roundup-Ready Soybean (RRS). Two DNA sequences, taxon (lectin) and event-specific (RR), are targeted via hybridization onto magnetic beads. Both sequences are simultaneously detected by performing the immobilization, hybridization and labeling steps in a single tube and parallel electrochemical readout. Hybridization is performed in a sandwich format using signaling probes labeled with fluorescein isothiocyanate (FITC) or digoxigenin (Dig), followed by dual enzymatic labeling using Fab fragments of anti-Dig and anti-FITC conjugated to peroxidase or alkaline phosphatase, respectively. Electrochemical measurement of the enzyme activity is finally performed on screen-printed carbon electrodes. The assay gave a linear range of 2-250Â pM for both targets, with LOD values of 650Â fM (160Â amol) and 190Â fM (50Â amol) for the event-specific and the taxon-specific targets, respectively. Results indicate that the method could be applied for GMO quantification below the European labeling threshold level (0.9%), offering a general approach for the rapid quantification of specific GMO events in foods.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
C. Lorena Manzanares-Palenzuela, Noemà de-los-Santos-Álvarez, MarÃa Jesús Lobo-Castañón, Beatriz López-Ruiz,