<p>Aflatoxin B<sub>1</sub> (AFB<sub>1</sub>), a potent mycotoxin, poses a critical threat to global food safety, demanding analytical methods with exceptional sensitivity. Here, we introduce a homogeneous electrochemiluminescence (ECL) biosensor that operates on a novel CRISPR-actuated electrostatic gating mechanism. The core of our strategy relies on controlling the access of ECL reporters to a positively charged electrode surface (PAH-ITO). In the absence of AFB<sub>1</sub>, cationic Ru(phen)<sub>3</sub><sup>2+</sup> reporters are electrostatically repelled from the electrode, resulting in a low background signal. The presence of AFB<sub>1</sub> triggers a CRISPR/Cas12a enzymatic cascade, which activates its trans-cleavage activity to release a highly anionic hybridization chain reaction (HCR) scaffold from magnetic beads (MB). This scaffold serves as a nanocarrier, capturing the Ru(phen)<sub>3</sub><sup>2+</sup> reporters and, by virtue of its strong negative charge, shuttling them to the electrode through potent electrostatic attraction. This action effectively “opens” the electrostatic gate, switching on a robust ECL signal. By synergistically integrating the high specificity of the aptamer-CRISPR system with the immense signal amplification of the HCR scaffold, all under the control of a charge-dominant switch, our biosensor achieves an outstanding limit of detection of 0.121&#xa0;fg/mL and a broad linear range from 1&#xa0;fg/mL to 100 pg/mL. Its successful application in spiked food samples validates its practicality and robustness, presenting a powerful new paradigm for designing minimal-background, high-gain ECL sensors for mycotoxin determination.</p> Graphical Abstract <p></p>

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An electrochemiluminescence biosensor governed by a CRISPR-actuated electrostatic gate for ultrasensitive aflatoxin B1 detection

  • Fei Yi,
  • Zhixin Li,
  • Fan Jiang,
  • Zhule Zhang,
  • Yingmei Chen,
  • Zhe Zhao,
  • Xiaoyu Deng,
  • Hao Chen,
  • Shaohua Xu,
  • Yingzhou Tao

摘要

Aflatoxin B1 (AFB1), a potent mycotoxin, poses a critical threat to global food safety, demanding analytical methods with exceptional sensitivity. Here, we introduce a homogeneous electrochemiluminescence (ECL) biosensor that operates on a novel CRISPR-actuated electrostatic gating mechanism. The core of our strategy relies on controlling the access of ECL reporters to a positively charged electrode surface (PAH-ITO). In the absence of AFB1, cationic Ru(phen)32+ reporters are electrostatically repelled from the electrode, resulting in a low background signal. The presence of AFB1 triggers a CRISPR/Cas12a enzymatic cascade, which activates its trans-cleavage activity to release a highly anionic hybridization chain reaction (HCR) scaffold from magnetic beads (MB). This scaffold serves as a nanocarrier, capturing the Ru(phen)32+ reporters and, by virtue of its strong negative charge, shuttling them to the electrode through potent electrostatic attraction. This action effectively “opens” the electrostatic gate, switching on a robust ECL signal. By synergistically integrating the high specificity of the aptamer-CRISPR system with the immense signal amplification of the HCR scaffold, all under the control of a charge-dominant switch, our biosensor achieves an outstanding limit of detection of 0.121 fg/mL and a broad linear range from 1 fg/mL to 100 pg/mL. Its successful application in spiked food samples validates its practicality and robustness, presenting a powerful new paradigm for designing minimal-background, high-gain ECL sensors for mycotoxin determination.

Graphical Abstract