Preparation and characterization of IgY antibody and its application in immunochromatographic assay for bongkrekic acid and its isomer

Egg yolk immunoglobulin (IgY) has emerged as a promising alternative to monoclonal antibodies (mAbs) due to its facile extraction, higher yield, and greater tolerance to organic solvents. This work developed a selective IgY antibody against bongkrekic acid (BA) and isobongkrekic acid (IsoBA), the lethal toxins produced by Burkholderia gladioli pv. Cocovenenans (BGC), which led to severe food poisoning incidents and resulted in casualties. In detail, the purified cBA was first conjugated with a carrier protein to generate an immunogen and immunized hens, followed by an optimized purification protocol, attaining a high-affinity anti-BA IgY with minimal cross-reactivity. Based on the obtained anti-BA IgY, a rapid and sensitive immunochromatographic assay (ICA) was developed and integrated with a smartphone. The linear range of ICA was 0.72–4.41 μg/kg with a limit of detection (LOD) of 0.42 μg/kg. Recovery rates ranged from 82.2 % to 106.4 % in spiked rice flour, agaric, and tremella, and there was no statistically significant deviation from results obtained by LC-MS/MS in blind samples. Compared to mAb-based ICAs, IgY-based ICAs offer some significant advantages, including a non-invasive production process that adheres to ethical animal welfare standards, high production yields, and exceptional tolerance to organic solvents. These attributes position IgY as a viable alternative for future commercial ICA development.