Ultrasensitive competitive detection of patulin toxin by using strand displacement amplification and DNA G-quadruplex with aggregation-induced emission.

A novel sensitive assay was established by using strand displacement amplification (SDA) and DNA G-quadruplex with aggregation-induced emission (AIE) for the detection of patulin (PAT) toxin. The complementary DNA (cDNA) of the aptamer and PAT competed for binding to aptamer-modified magnetic beads. The cDNA was obtained by magnetic separation and used as a primer in SDA to produce a large amount of G-base single-stranded DNA (ssDNA). They can form the G-quadruplex to be combined with the AIE of TTAPE dye, which features a special combination of G-quadruplex that amplify the fluorescent signals. This work can reach a lower detection limit of 0.042 pg mL−1 with a wide linear range of 0.001–100 ng mL−1 for PAT detection than other methods. The results also showed good recoveries of 97.8%–104% and 101.7%–105.3% in spiked apple and grape juices, respectively. The assay used for the detection of PAT exhibits high sensitivity and good specificity. It also provides a stable and reliable platform for detecting other small-molecule toxins. Image 1 • This study firstly uses strand displacement amplification and DNA G-quadruplex with aggregation-induced emission (AIE) to detect small-molecule patulin toxin, achieving signal amplification to obtain a lower limit of detection. • The AIE material provides a more convincing experimental validation. Compared with general fluorescent dyes, the combination effect is better and the sensitivity is higher. • This work provided a new idea for the detection of mycotoxins, which is more convenient and faster than the traditional method. • This approach provided a broader perspective on the establishment of rapid food safety testing methods. [ABSTRACT FROM AUTHOR]