Electrochemical genosensor for the detection of Alexandrium minutum dinoflagellates

Abstract

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.

Keywords: Alexandrium minutum; Chronoamperometry; Dinoflagellate; Electrochemical genosensor; Sandwich format hybridization.