Immunosensor based on antibody-functionalized MoS₂ for rapid detection of avian coronavirus on cotton thread

Infectious bronchitis virus (IBV), an avian coronavirus, significantly affects the performance of both the egg-laying and meat-type birds causing the foremost of economic loss in poultry industry. This paper aims to develop a rapid, low-cost, and sensitive biosensor for IBV detection by using molybdenum disulfide (MoS₂). MoS₂ is a 2-D nanosheet which has strong high fluorescence-quenching ability when applied to a dye-labeled antibody (Ab). In this paper, we developed an Ab-functionalized MoS₂-based fluorescent immunosensor, which utilized the fluorescence resonance energy transfer (FRET) between the MoS₂ and fluorescence dye during the Ab-antigen interaction. The assay was performed on a low-cost cotton thread-based microfluidic platform due to the good wicking property and flexibility. Upon the optimization of assay conditions, the immunosensor demonstrated remarkable sensitivity of 4.6× 10^-2 EID₅₀ per mL and specificity with a dynamic linear response range of 10²-10⁶ EID₅₀ per mL for IBV standard solutions. The developed immunoassay successfully detected the IBV spiked chicken serum with satisfactory results. The foregoing presents its potential application for on-farm detection.