Development of an electrochemical genosensor for detection of viral hemorrhagic septicemia virus (VHSV) using glycoprotein (G) gene probe

Viral hemorrhagic septicemia virus (VHSV) is the causative agent of a highly contagious disease of both saltwater and freshwater fish around the world. VHSV, a member of viral Rhabdoviridae family, listed as a notifiable pathogen by the World Organization for Animal Health (OIE). This study was aimed to fabricate an electrochemical DNA genosensor for detection of the VHSV Glycoprotein gene. Immobilization of the DNA probe was carried out through self-assembly by thiol binding on RGO/Au-nanocomposite-modified pencil graphite electrode (PGE). The modified PGE was characterized by field emission scanning electron microscope (FESEM). The hybridization between the target sequences and the probe was analyzed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) methods. Detection in these methods was performed by a decrease in the current and an increase in the charge transfer resistance (Rct) followed by target nucleic acids hybridization with biosensor probe. Genosensor sensitivity was tested by some mismatched sequences by 1, 2, and 3 bases in the methylene blue solution. The limit of detection (LOD) was at 125 pM of DNA target within the linear range of 10(-4) to 10(-10) M. The selectivity, stability, regeneration, and reproducibility of the fabricated electrochemical DNA biosensor were acceptable. A pilot analysis on real samples confirmed its applicability. Altogether, the genosensor can be suggested for direct detection of negative sense RNA genome of VHSV because of its fast assay, and high sensitivity.