HCR/DNAzyme driven cascade signal amplified fluorescent aptasensor for detecting deoxynivalenol in food

Deoxynivalenol (DON), a prevalent mycotoxin, poses a serious global health threat, necessitating ultrasensitive detection methods for its trace levels in food. Herein, we developed fluorescent aptasensor by integrating hybridization chain reaction (HCR) with DNAzyme(Deoxyribozyme)-mediated cascade amplification. The core innovation of this study lies in its self-sustaining feedback loop mechanism: DON triggers the initial HCR and simultaneously assembles DNAzyme; after the DNAzyme cleaves the substrate, it regenerates the trigger strand containing the complete cDNA sequence, thereby initiating a new round of HCR and forming a "single trigger multiple cycle" feedback loop to achieve signal cascade amplification. This synergistic strategy conferred high sensitivity, enabling a wide linear range (1 pg/mL to 100 ng/mL R² = 0.9952) and an ultralow limit of detection(LOD) 0.3092 pg/mL. The sensor also exhibited excellent stability, reproducibility, and specificity. Spike recovery results (89.4 %-102.5 %) aligned closely with the isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) reference method (81.7 %-104 %), confirming its accuracy and reliability for rapid DON screening in food samples. This work not only provides a robust tool for the trace detection of DON but also proposes a novel design strategy for the development of high-performance biosensing platforms.