Rapid and sensitive detection of ochratoxin A using antibody-conjugated gold nanoparticles based on Localized Surface Plasmon Resonance

The regulation of tolerable levels of ochratoxin A in food for human and animal consumption has been defined in some countries. To meet these levels, simpler, more efficient, and faster analytical methods are being developed to facilitate the identification of this dangerous contaminant in food. Here, we combined gold nanoparticles (AuNPs) with anti-ochratoxin A (OTA) IgG to detect elementary levels of OTA based on Localized Surface Plasmon Resonance. AuNPs were prepared with trisodium citrate and characterized by UV-visible spectroscopy, X-ray, dynamic light scattering, and transmission electron microscopy. The conjugation of AuNPs to IgG antiOTA was confirmed by bathochromic shift (UV-vis) and RAMAN spectroscopy. The sensitivity of the nanosensor was investigated by measuring LSPR band lambda max shifts. Our results suggest this assay is highly sensitive, with a lower detection limit of about 0.001 pg mL-1. The LSPR nanosensor reduced detection limits by roughly 10 times compared to other methods. We demonstrated that the approach investigated here is a rapid and sensitive method for OTA detection.

Automated summary

This study demonstrates a rapid and sensitive method for detecting trace levels of ochratoxin A in food by combining gold nanoparticles with anti-ochratoxin A IgG. The sensitivity of this nanosensor is very high, with a lower detection limit of about 0.001 pg mL-1, reducing detection limits by roughly 10 times compared to other methods.