Gold nanoparticle-based colorimetric aptasensor for rapid detection of mutiple mycotoxins in rice

A novel, simple and rapid colorimetric aptasensor for mutiple mycotoxins (Ochratoxin A (OTA) and aflatoxin B1 (AFB1)) detection was developed using unmodified gold nanoparticles (AuNPs). In the work, the high affinity of OTA and AFB1 aptamers were employed as the recognition elements for the colorimetric determination of OTA and AFB1. In the absence of mycotoxins, the aptamers were directly adsorbed to the AuNPs surface through the electrostatic attraction to further prohibit the aggregation induced by high concentration of salt and the solution remain red. In the presence of mycotoxins, the corresponding aptamers-target complex were formed and corresponding aptamers were detached from the surface of AuNPs, leading to the aggregation of AuNPs under optimal salt solution and the color change. By spectroscopic quantitative analysis and visual analysis, the LOD of OTA and AFB1 is down to 0.015 ng/mL and 0.125 ng/mL, respectively. Furthermore, colorimetric aptasensor showed high specificity in the presence of other interfering mycotoxins. Finally, the developed aptasensor was applicable to detect OTA and AFB1 in rice samples with satisfactory performance. Our strategy show great potentials for rapid and sensitive detection of OTA and AFB1 on the-site analysis.