Simultaneous detection of fumonisin B1 and ochratoxin A using dual-color, time-resolved luminescent nanoparticles (NaYF4: Ce, Tb and NH2-Eu/DPA@SiO2) as labels.

A rapid and highly sensitive time-resolved fluorescence (TRF)-based aptasensor for simultaneous recognition of mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1) was developed using multi-color, Ln3+-doped time-resolved fluorescence nanoparticles (TRF-NPs) (NaYF4: Ce, Tb and NH2-Eu/DPA@SiO2 NPs) coupled with complementary strand DNA (cDNA) as luminescence probe and aptamers-conjugated amine-functionalized Fe3O4 magnetic nanoparticles (MNPs) act as a capture probe. Under the optimized conditions, the time-resolved fluorescence intensities at 544 and 618 nm corresponded with Tb3+ and Eu3+, respectively, were used to measure FB1 (Y = 19,177.1 + (- 12,054.4)x, R2 = 0.9917) and OTA (Y = 4138.8 + (- 11,182.6)x, R2 = 0.9924), respectively. The limits of detection (LODs) for FB1 and OTA were 0.019 pg mL-1 and 0.015 pg mL-1, respectively, which were much lower than previously described methods for simultaneous recognition of mycotoxins OTA and FB1 while detection range varied from 0.0001-0.5 ng mL-1. This aptasensor was effectively applied to quantity FB1 and OTA in maize samples and results were compared with ELISA method. This is the first reported time-resolved fluorescence (TRF)-based aptasensor to detect two agriculturally important toxins in the maize. The developed aptasensor has potential to be used for detection of toxins in food safety fields. Graphical abstract.