A simple and rapid biosensor for ochratoxin A based on a structure-switching signaling aptamer

• Published in: Food control Vol. 25; no. 2; pp. 555 - 560
• Main Authors: Chen, Junhua, Fang, Zhiyuan, Liu, Jie, Zeng, Lingwen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2012
• Subjects: aflatoxin B1; complementary DNA; corn; detection limit; Fluorescence; food quality; food safety; foods; monitoring; Mycotoxin biosensor; Ochratoxin A; Structure-switching aptamer; zearalenone; Fluorescence; Mycotoxin biosensor; Ochratoxin A; Structure-switching aptamer
• ISSN: 0956-7135; 1873-7129
• DOI: 10.1016/j.foodcont.2011.11.039

A fast and reliable sensing platform has been developed for the detection of mycotoxin ochratoxin A (OTA) based on a target-induced structure-switching signaling aptamer. In the absence of target, a fluorescein-labeled OTA aptamer hybridizes to a complementary DNA strand containing a quencher moiety, bringing the fluorophore and the quencher into close proximity for highly efficient fluorescence quenching. Upon OTA addition, a conformational change in the aptamer releases the quencher-containing DNA strand, generating a strong concentration-dependent fluorescent signal. Using this technique, the entire detection and analysis process of OTA can be completed within 1 min. Under optimized assay conditions, a wide linear detection range (from 1 to 100 ng/mL) was achieved with a detection limit down to 0.8 ng/mL. Additionally, the proposed assay system exhibited high selectivity for OTA against other mycotoxins (aflatoxin B1 and zearalenone) and limited interference from the structural analog ochratoxin B. The biosensor was also applied to a non-contaminated corn material spiked with a dilution series of OTA, obtaining recoveries from 83% to 106%. Utilization of the proposed biosensor for quantitative determination of mycotoxins in food samples may provide significant improvements in quality control of food safety through a simple, rapid, and sensitive testing system for agricultural products monitoring. ► A fast and reliable biosensor for Ochratoxin A monitoring based on a structure-switching signaling aptamer. ► Ochratoxin A triggered the release quencher-containing cDNA from fluorescein-labeled Ochratoxin A aptamer. ► Wide linear range (1–100 ng/mL) and low detection limit (0.8 ng/mL) were achieved. ► It applies for real sample analysis because of the high selectivity. ► That is an alternative tool for rapid on-site screen and detection of mycotoxin.