A novel impedimetric immunosensor for the detection of chicken interferon-gamma based on a polythionine and gold nanoparticle modified glassy carbon electrode

Currently, there is no effective detection method for chicken interferon-gamma (ChIFN-gamma), therefore it is of great significance to develop a new, accurate and sensitive method for the rapid detection of ChIFN-gamma to solve the problems which are directly impeding the in-depth research of immune regulatory factors and poultry immune responses, and which are preventing the analysis and evaluation of the immunity of poultry in diseases or after vaccination. This paper is the first report of a novel label-free electrochemical impedimetric immunosensor for the sensitive detection of ChIFN-gamma, based on a 3E(3) monoclonal antibody against chicken interferon-gamma (denoted as 3E(3)McAb) immobilized on a glassy carbon electrode modified with polythionine and gold nanoparticle self-assembled layers. The surface modification steps were characterized by scanning electron microscopy and electrochemical impedance spectroscopy (EIS). Detection was performed by measuring the relative change in impedance before and after the 3E(3)McAb-ChIFN-gamma reaction by EIS. Under the optimized conditions, the relative change in impedance was proportional to the logarithmic value of ChIFN-gamma concentrations in the range of 0.10 to 1.0 x 10(3) ng mL(-1) (r = 0.9946) with a detection limit of 0.10 ng mL(-1). Compared to the traditional method of enzyme-linked immunosorbent assay, the proposed method performed a low-cost, sensitive, quantitative detection of ChIFN-gamma in real samples with satisfactory results, indicating that the developed immunoassay could be a promising alternative approach for the detection of ChIFN-gamma.