Development of a sensitive label-free electrochemical immunosensor for detection of chickpea chlorotic dwarf virus

Chickpea chlorotic dwarf virus (CpCDV) is one of the most important pathogenic viruses of chickpea that can have devastating effects on the economy and food security of people. Herein, we aim to develop a new electrochemical label-free immunosensor to detect Chickpea chlorotic dwarf virus (CpCDV) with high sensitivity and rapidity. To achieve this, a combination of room temperature ionic liquid (IL), reduced graphene oxide (rGO), and Prussian blue (PB) was first used to modify the glassy carbon electrode (GCE). In addition, Au nanoparticles (AuNPs) were electrodeposited on the electrode surface. The morphology of the surface was investigated using a field emission scanning electron microscope (FE-SEM). The techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to discover the properties of each component in the function of the fabricated electrode. The results showed that the AuNPs/PB-rGO-IL/GCE electrode possessed excellent electrochemical activity, which led to a significantly improved signal response of PB. Subsequently, the anti-CpCDV was immobilized and the non-responsive sites were blocked by BSA. Then, the different parameters affecting the immunosensor response, such as pH, incubation time, and electrodeposition time of AuNPs, were investigated. Interestingly, the fast Fourier transform square wave voltammetry (FFT-SWV) technique was used to detect the CpCDV antigen. The presented immunosensor demonstrated a linear behavior in a wide range from 0.05 to 50 μg/mL and a detection limit (S/N= 3) of 0.01 μg/mL. In addition, the proposed immunosensor can be considered an acceptable candidate for the detection of CpCDV due to its satisfactory selectivity in the real matrix and its reproducibility, durability and stability.