A novel magneto-gold nanohybrid-enhanced lateral flow immunoassay for ultrasensitive and rapid detection of ochratoxin A in grape juice

Conventional gold nanoparticle-based lateral flow immunoassay (LFIA) usually suffers a huge challenge in measuring target concentration in food matrices with dark color because of its poor resistance to the background matrix and color interference. To address this issue, we first report a novel bifunctional magneto-gold nanohybrid (MGNH) for the simultaneous magnetic separation and colorimetric target sensing by integrating MGNHs into LFIA. Under optimum conditions, an ultrasensitive detection of ochratoxin A (OTA) in grape juice was achieved with a limit of detection at 0.094 ng mL(-1). The average recoveries of this MGNH-LFIA ranged from 92.31% to 108.97% with a coefficient of variation of below 12%. The excellent selectivity of our MGNH-LFIA against OTA was demonstrated. Besides, our MGNH-LFIA is comparable to liquid chromatography coupled with mass spectrometry in terms of accuracy, reproducibility, and practicability. The designed MGNH-LFIA platform is readily extended for improving other small molecule detection in food samples.