Gold nanoparticle-based electrochemical immunosensor for the detection of Russell’s viper venom using IgY antibodies

Abstract

In this study, we have developed for the first time a sensitive electrochemical immunosensor by electrostatically immobilizing IgY antibodies onto the citrate capped gold nanoparticle (ctAuNP) functionalized glassy carbon electrode (GCE) for the detection of Russell’s Viper (RV) venom in human blood and serum. Initially, the ctAuNP was prepared by a simple citrate reduction method. Simultaneously a novel approach of preparing RV IgY antibodies was raised in immunized chicken for this study. The ctAuNP-IgY modified electrode was characterized using cyclic voltammetry (CV) and the sensing was carried out using electrochemical impedance spectroscopy (EIS). The Nyquist plot was recorded for different concentrations of RV venom using signals produced during antigen–antibody interactions. The presence of ctAuNP helps in the adsorption of antibodies and also enhances the conductivity of the sensor. The limit of detection (LOD) was estimated to be 0.74 µg/mL with a linear range from 3.34 to 6.68 µg/mL of RV venom. The sensor was tested in both human serum and blood samples which showed a satisfactory recovery percentage ranging from 87.3 % to 110.4 % and 84.6 % to 108.5 % respectively. Stability studies showed that the surface-modified electrode retained 87 % of the initial sensitivity after storage at 4 °C for one week.