Microarray surface enhanced Raman scattering based immunosensor for multiplexing detection of mycotoxin in foodstuff

A surface enhanced Raman scattering (SERS) based immunosensor was developed for the detection of three mycotoxins (aflatoxin B1, AFB1; zearalenone, ZEA; ochratoxin A, OTA) in foodstuff. Gold nanoparticles (GNPs) were labeled with 5,5-dithiobis(succinimidyl-2-nitrobenzoate) (DSNB) as Raman reporter and covalently linked with anti-mycotoxin antibodies as SERS nanoprobes, while AFB1-BSA, ZEA-BSA, and OTA-BSA conjugates were covalently linked onto micro-array gold surface as corresponding capture addresses. This design allows three independent immunoreactions multiplexed on a single gold chip. After optimization, the limits of detection of the developed assay are 0.061-0.066 μg/kg for AFB1, 0.53-0.57 μg/kg for ZEA, and 0.26-0.29 μg/kg for OTA in foodstuff. The spiked experiments presented an acceptable assay accuracy with recovery of 83.8%-108.1% and a reasonable assay precision with variation of coefficient less than 15%. Furthermore, the analysis of actual samples by our method demonstrated consistent results by comparison with conventional instrumental analysis. These results indicate that the developed SERS immunosensor can be a promising tool for simultaneously and rapidly monitoring multiple-mycotoxin levels in foodstuff.