Electrochemical genosensor for the detection of Alexandrium minutum dinoflagellates

This work addresses the development of a disposable electrochemical genosensor for the detection of the toxic dinoflagellate, Alexandrium minutum. Analyzing public databases, a specific 70 bp DNA probe, targeting A. minutum, was selected and designed. The genosensor methodology implied the immobilization of a A. minutum-specific DNA-capture probe onto screen-printed gold electrodes (SPGE). To improve both the selectivity and to avoid strong secondary structures, that could hinder the hybridization efficiency, a sandwich format of the A. minutum gene was designed using a fluorescein isothiocyanate-labelled signaling DNA probe and enzymatic amplification of the electrochemical signal. Using this electrochemical genosensor, a concentration range from 0.12 to 1.0 nM, a LD of 24.78 pM with a RSD <5.2% was determined. The genosensor was successfully applied to the selective analysis of the targeted A. minutum specific region denatured genomic DNA extracted from toxic dinoflagellates present in the Atlantic Ocean.