Electrochemical Genosensors for Plant Species Identification: Focus on Chestnut and Heather

Abstract

In this study, two disposables electrochemical genosensors based on the hybridization reaction between two complementary DNA probes were developed to determine the botanical origin of two plant species: Erica arborea (Heather) and Castanea sativa (Chestnut). Analyzing public databases, two sequences were specifically cut and designed to identify the heather e chestnut DNA in real samples. The genosensors' construction were carried out in three stages (i) Sensory phase: creation of a mixed self-assembled monolayer (SAM) consisting of the thiolated DNA and mercaptohexanol (MCH) on the surface of the disposable electrode; (ii) Promotion of the DNA hybridization reaction in a “sandwich” format to increase selectivity and; (iii) Electrochemical detection of the hybridization reaction through the evaluation of the reduction reaction of the tetramethylbenzidine/peroxide (TMB/H2O2) substrate. Using chronoamperometry, a linear correlation was obtained between the electrochemical current and the concentration of DNA-target probe in a 0.03 to 2.00 nmol/L range for E. arborea and 0.03 to 1.00 nmol/L for C. sativa. These genosensors detected the hybridization reaction between the synthetic and real DNA probes of both plants. Therefore, electrochemical genosensors emerge as a simple and promising analytical technique that can be used to authenticate food products that contain heather and chestnut DNA.