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<p>Herein, an electrochemical/photoelectrochemical (EC/PEC) dual-mode sensing platform based on carbon dots/liquid exfoliated graphene (CDs/LEG) nanocomposites was developed in this work. The CDs/LEG heterogeneous effectively exploited the excellent photoelectric activity of CDs and the high conductivity of LEG. Ferrocene-labelled aptamer (Fc-Apt) and methylene blue-labelled complementary DNA (MB-cDNA) were introduced as dual-signal probes. Upon aflatoxin B1 (AFB<sub>1</sub>) binding, it competitively displaced MB-cDNA, restoring Fc-Apt hairpin conformation and causing MB to move away from the electrode surface while Fc approached it. This conformational change significantly increased the <i>I</i><sub><i>Fc</i></sub> to <i>I</i><sub><i>MB</i></sub> peak current ratio (<i>I</i><sub><i>Fc</i></sub>/<i>I</i><sub><i>MB</i></sub>), enhancing the EC signals; meanwhile, the aptamer complex immobilized on the electrode surface reduced the PEC signals through spatial site-blocking and light-shielding effects. The dual-mode responded synergistically to form a unique self-validation mechanism, which showed excellent linearity over the AFB<sub>1</sub> concentration range of 0.01-100 ng/mL, with detection limits (LOD) of 1.356 pg/mL (EC mode) and 0.087 pg/mL (PEC mode).</p> Graphical Abstract <p></p>

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A simple carbon-based electrochemical/photoelectrochemical dual-mode aptasensor for the detection of aflatoxin B1

  • 期刊论文

  • 发表日期：

    2025年12月10日

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  • Yijun Tan,
  • Dan Meng,
  • Fang Li,
  • Mingming Luo,
  • Ying Li,
  • Panpan Dong,
  • Longping Xu,
  • Ruowei Liu,
  • Zijian Wu

摘要

Herein, an electrochemical/photoelectrochemical (EC/PEC) dual-mode sensing platform based on carbon dots/liquid exfoliated graphene (CDs/LEG) nanocomposites was developed in this work. The CDs/LEG heterogeneous effectively exploited the excellent photoelectric activity of CDs and the high conductivity of LEG. Ferrocene-labelled aptamer (Fc-Apt) and methylene blue-labelled complementary DNA (MB-cDNA) were introduced as dual-signal probes. Upon aflatoxin B1 (AFB1) binding, it competitively displaced MB-cDNA, restoring Fc-Apt hairpin conformation and causing MB to move away from the electrode surface while Fc approached it. This conformational change significantly increased the IFc to IMB peak current ratio (IFc/IMB), enhancing the EC signals; meanwhile, the aptamer complex immobilized on the electrode surface reduced the PEC signals through spatial site-blocking and light-shielding effects. The dual-mode responded synergistically to form a unique self-validation mechanism, which showed excellent linearity over the AFB1 concentration range of 0.01-100 ng/mL, with detection limits (LOD) of 1.356 pg/mL (EC mode) and 0.087 pg/mL (PEC mode).

Graphical Abstract