A ratiometric fluorescent biosensor based on catalytic hairpin assembly reaction for ultrasensitive detection of aflatoxin-producing genes

作者：Tao Yu, Xin Chen, Danni Sun, Dezhao Kong, Zhirong Wang, Lin Feng, Yaqi Li · 发表于：Food Bioscience · 年份：2024 · DOI：10.1016/j.fbio.2024.105565 · 被引用次数：8 · 研究领域：Advanced biosensing and bioanalysis techniques、Carbon and Quantum Dots Applications、Biosensors and Analytical Detection

Aflatoxins as the world's most toxic contamination is metabolized by Aspergillus flavus and its production is closely related to aflatoxin-producing genes. It is significant to monitor the aflatoxin-producing genes as early as possible to prevent the contamination and spread of aflatoxins. Therefore, a label-free and free separation fluorescent biosensor using the selective cation exchange reaction in conjunction with the signal amplification of catalytic hairpin assembly (CHA) was developed for the detection of aflatoxin-producing gene utilizing CdTe quantum dots (CdTe QDs) and Nitrogen-doped carbon quantum dots (NCQDs) as the beacon molecule. There were two types of hairpin structures in this sensing system, hairpin probe 1 (HP1) was generated by Ag + and the recognition probe with the complex C-Ag + -C structure and hairpin probe 2 (HP2) was the DNA fragments showing a hairpin arrangement. Target nor-1 gene may activate the CHA, which created a significant quantity of HP1-HP2 double-stranded DNAand recycled the target nor-1 gene. The released amounts of Ag + suppressed the fluorescence signal of CdTe QDs, while it wasn't observed the discernible effect on NCQDs. This fluorescent biosensor displayed the excellent sensitivity for aflatoxin-producing nor-1 gene in a dynamic range of 5 pM–50 nM with a detection limit of 1.66 pM. This fabricated sensor also showed the visible distinguish for different concentrations of nor-1 gene. It exhibited the potential to offer vital enhan...