Abstract: A dual-signal fluorescent aptasensor based on gold nanoflower (AuFL) was constructed for the simultaneous detection of ochratoxin A (OTA) and zearalenone (ZEN). Single-stranded DNA containing OTA and ZEN aptamers were covalently cross-linked on the surface of AuFL as a nanocarrier and hybridized with complementary DNA labeled with two fluorescent dyes (FAM and Cy3) to prepare a DNA functionalized nanoprobe. Because of fluorescence resonance energy transfer (FRET) between the fluorescent dyes and AuFL, the nanoprobe itself had no fluorescence. When OTA and ZEN were added, FAM and Cy3 were shed from the probe’s surface, disturbing the FRET process and consequently restoring the fluorescence of both fluorescent dyes. Under optimized conditions, the linear range was from 0.05 to 500 ng/mL, and the detection limit was 0.017 ng/mL for OTA; the linear range was from 0.1 to 500 ng/mL, and the detection limit was 0.033 ng/mL for ZEN. The dual-signal fluorescent aptasensor had good selectivity and reproducibility and was successfully applied to the detection of OTA and ZEN in real wine samples.

Key words: dual-signal; aptasensor; ?uorescence detection; ochratoxin A; zearalenone