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

Authors：Zhang, Man; Wang, Yu; Sun, Xuan; Bai, Jialei; Peng, Yuan; Ning, Baoan; Gao, Zhixian^*; Liu, Baolin^*

Source：Analytica Chimica Acta, 2020, 1106: 161-167.

DOI：10.1016/j.aca.2020.01.064

• AIE
• Aptamer
• G-quadruplex
• Patulin
• SDA
• TTAPE

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.