A Novel Fluorescent FRET Hairpin Probe Switch for aflD Gene Detection in Real Fermented Soybean Paste

• DOI: 10.1007/s12161-021-02080-7
• Publication Date: 2021-07-06T00:02:36Z
• Authors: Yaqi Li; Tao Yu; Jiyang Li; Dezhao Kong; Qiaoqiao Shi; Chang Liu; Chunwang Dong
• Keywords: 02 engineering and technology; 0210 nano-technology

The development of detection method for aflatoxin gene cluster in Aspergillus flavus and Aspergillus parasiticusis is an effective approach to prevent the widespread of aflatoxins, which are considered as extremely, toxic substances. Herein, a hairpin DNA-assisted fluorescence probe switch based on Forster resonant energy transfer (FRET) was designed. In this work, the two terminals of hairpin DNA probe were combined with CdTe/CdS quantum dots as donor and gold nanoparticles (AuNPs) as acceptor respectively to fabricate the FRET hairpin probe switch, which were utilized to detect the aflatoxigenic fragment of aflD genes for the first time. In the absence of target DNA, the hairpin probe formed the double stem loops state to trigger the FRET to induce the fluorescence-quenching (turning off). With the addition of target DNA, the specific interaction between target and hairpin probe switch brought about the separation of fluorescent energy donor–acceptor pairs to create an increasing fluorescence response (turning on). Consequently, the fluorescence intensity recovers can be employed to detect aflD genes in homogenous phase through optical responses. This proposed FRET hairpin probe switch performed a great limit of detection of 0.02 nM with a linear range of 0.05–200 nM under optimal conditions. Furthermore, the feasibility of the fabricated strategy was demonstrated in fermented soybean paste with the advantages of simplicity, rapidity, and sensitivity, which indicated that this method exhibited the potential and practicability in foodborne biological samples.