Ultrasensitive quantitation of Paraquat based on a small molecule-induced dual-cycle amplification strategy

• Published in: Biosensors & bioelectronics Vol. 240; p. 115640
• Main Authors: Chen, Hao-Ran, Zhang, Shun, Chen, Tao, Yang, Wei-Guo, Su, Ming-Li, Fu, Guan-Yan, Yi, Wei-Jing, Yuan, Ruo, Xu, Shang-Cheng, Liang, Wen-Bin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2023
• Subjects: biosensors; CRISPR; detection limit; Dual cycle; Fluorescence; Food safety; Paraquat; pesticide residues; Dual cycle; Fluorescence; CRISPR; Paraquat; Food safety
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2023.115640

Paraquat (PQ) is a typical biotoxic small molecule. Knowledge of how to directly introduce it into cyclic amplification rather than transform it into a secondary target is lacking in current analytical methods. Considering the urgent need for trace pesticide residue detection and the inherent defects of small molecule analysis, a CRISPR/Cas12a-driven small molecule-induced dual-cycle strategy was developed based on the immune competition method. The key to signal amplification is the mutual activation and acceleration between Cycle 1 triggered by the small molecule and Cycle 2 driven by CRISPR/Cas12a. Impressively, small molecules have been successfully incorporated into the dual-cycle strategy, which achieves a low detection limit (3.1 pg/mL) and a wide linear range (from 10 pg/mL to 50 μg/mL). Moreover, the designed biosensor was successfully employed to evaluate the PQ residual level in real samples and showed effective implementation for the bioanalysis of small molecule targets and pesticide residue-related food safety.