Electrochemical immunosensor for detection of avian Salmonellosis based on electroactive reduced graphene oxide (rGO)...

A novel reduced graphene oxide based (rGO) fluorine doped tin oxide (FTO) electrode was fabricated to explore the interaction of Salmonella serovars (Salmonella gallinarum, and Salmonella pullorum) with specific antibodies. Reduced graphene oxide (rGO) was labelled with S. gal and S. pul-Ab via carbodiimide activation. The biophysical characterization of fabricated electrode was done by Fourier-transform infrared spectroscopy (FT-IR), Raman Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), cyclic voltammetry (CV), and differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The optimization of fabricated electrode was done for various physico-chemical parameters. Under optimum conditions, the immunosensor exhibited a linear detection range (1- 1 × 10⁵ cells) with 37 and 25 viable cells of S. gal and S. pul, respectively. The developed FTO/rGO/S.gal or S.pul-Ab/Ag immunosensor successfully detected S. gal or S. pul up to 51 and 37 cells, respectively in faecal samples and 218 and 173 cells, respectively in meat samples. FTO/rGO/S.gal or S.pul-Ab/Ag immunosensor revealed satisfactory response, and exhibited relatively low detection limit along with reproducibility. The proposed sensing model can be used as an alternative quantitative tool for the rapid and sensitive detection of Salmonellosis in meat and faecal samples.