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Engineered DNAzyme Enables Homogeneous Detection of Cereulide via Polychromic Fluorescence Modality.

Jingnan MengHaoran ShenLin LuoXi ZengJuan WangYingju LiuZhen-Lin Xu
Published in: Analytical chemistry (2023)
Cereulide, the exotoxin of emetic Bacillus cereus , has garnered considerable attention due to its capacity to produce foodborne poisonings and great chemical stability. Herein, a G-quadruplex-hemin DNAzyme-based biosensor was developed to detect cereulide in the homogeneous solution. Due to the special ring structure and high affinity to K + , cereulide can be attracted and intercalated into the G-quadruplex; thus, the properties of the G4 DNAzyme can be altered. The melting temperature ( T m ) of the G4 DNAzyme in the presence or absence of cereulide was 58.75 and 50.10 °C, respectively, proving the intercalation of cereulide into the G4 DNAzyme. By using the polychromic fluorescence modality of CdTe quantum dots and o -phenylenediamine to assess the variation in the catalytic activity of the DNAzyme, the intercalation of cereulide had bidirectional effects in G4 DNAzyme-mediated reactions, showing that the fluorescence intensity of CdTe quantum dots displayed a linear relationship with the concentration of cereulide from 0.16 to 40 μg/mL with the limit of detection (LOD) of 0.10 μg/mL, while the fluorescence intensity of DAP exhibited a linear relationship with the concentration of cereulide from 0.02 to 40 μg/mL with the LOD of 0.01 μg/mL. It will be a perspective step of controlling cereulide as a hazardous material in food or the environment.
Keyphrases
  • quantum dots
  • label free
  • living cells
  • energy transfer
  • single molecule
  • sensitive detection
  • high resolution
  • high intensity
  • mass spectrometry
  • risk assessment
  • loop mediated isothermal amplification