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Aggregation-induced emission (AIE) dyes are promising for labeling nucleic acid probes. Aptamer is one of the most appealing nucleic acid probes, and may enable to output signal response to target molecules by the direct use of single aptamer sequence. However, the concise sensing platform is often suffered from low sensitivity. In response, by the adoption of AIE dyes, we propose an intrinsic conformation response-leveraged aptamer probe (iconAptamer) for aflatoxin B 1 (AFB 1) detection. The design strategy lies in the synergetic utilization of AIE and fluorescence resonance energy transfer (FRET) effects. AIE dyes confer a much higher sensitivity for monitoring the response of aptamer towards AFB 1 compared to traditional DNA intercalation dyes. FRET process between AIE dyes and the terminal-labeled fluorophore would induce a distance effect in the structure-switching process, further leveraging the response signal. Consequently, the sensitivity of the aptamer probe was dramatically improved by over 2 orders. IconAptamer allowed to mix-to-read detection of AFB 1 contaminations at room temperature. The application of iconAptamer for AFB 1 detection in food and environmental samples has been demonstrated, with recovery rates of 91.8%–111.1%. IconAptamer would provide a simple, fast, convenient, and cost-effective platform for food safety control and environmental monitoring by broadening the target species. Based on aggregation-induced emission dye and FRET process for leveraging the Intrinsic conformation response of aptamer toward targets, a single-aptamer sequence-based assay was established, which enables sensitive and mix-to-read detection of aflatoxin B 1. Image 1 • A sensitive single-strand aptamer probe was built using AIE dye and FRET process. • Achieving mix-to-read analysis of aflatoxin B 1 , thus well fit for on-site detection. • Potential application for food safety control and environmental monitoring. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) dyes now serve as powerful tools for fluorescence analysis and biological imaging due to their light-up property in the aggregated state. Herein, we proposed an AIE dye-based aptasensor, enabling label-free and turn-on detection of mycotoxin. The positively charged AIE dyes would confer high-affinity to negatively charged aptamers and be lighted up by the aggregation process of dye molecules. Attributed to the resistance of ochratoxin A (OTA)-binding aptamer complex to enzyme digestion, label-free analysis of OTA could be realized via the synergetic utilization of AIE dyes and enzymatic digestion process. The digestion process could contribute to a signal to background ratio (S/B) of 1.71 for OTA detection. Remarkably, the adoption of AIE dyes would lead to a dramatic enhancement of over 104.5% of S/B compared to conventional nucleic acid dyes, thus favoring the sensitivity of the aptasensor. Only one aptamer sequence was involved in the assay, thus avoiding the complex structure design of aptamer probes. The AIE dye-based aptasensor could confer a limit of detection of 0.4 ng/mL for OTA detection. Besides, it exerted remarkable specificity for identifying OTA, and has been successfully applied for OTA analysis in wine and coffee. AIE dyes would be a compelling candidate in biohazard screening filed, and the proposed aptasensor would potentially provide a universal platform for on-site detection of food and environment contaminations. A label-free and turn-on aptasensor was built via aggregation-induced emission dye by the direct use of single aptamer sequence, allowing to detect mycotoxin in one test tube. Image 1 • A label-free aptasensor for mycotoxin was built via aggregation-induced emission dye. • The aptasensor achieved mycotoxin detection by the use of single-aptamer sequence. • The aptasensor may sever as facile platforms for food and environmental analysis. [ABSTRACT FROM AUTHOR]