A new amplified fluorescent aptasensor based on hairpin structure of G-quadruplex oligonucleotide-Aptamer chimera and silica nanoparticles for sensitive detection of aflatoxin B1 in the grape juice.

As one of the most toxic mycotoxins, aflatoxin B1 (AFB1) is a major food pollutant which can pose a high risk to human health. In this work, an accurate fluorescent sensing method was proposed for AFB1 determination, based on hairpin structure of G-quadruplex oligonucleotide-Aptamer chimera, silica nanoparticles coated with streptavidin (SNPs-Streptavidin) and N-methyl mesoporphyrin IX (NMM). The hairpin structure of chimera and SNPs-Streptavidin allowed AFB1 detection with high sensitivity and specificity. Moreover, the developed sensor could detect AFB1 in 30 min. The relative fluorescence intensity increased as AFB1 concentrations increased with a linear range of 30-900 pg/mL and a limit of detection (LOD) of 8 pg/mL. The constructed aptasensor was successfully employed to assess AFB1 spiked grape juice and human serum samples. The analytical recovery of AFB1 in the grape juice samples ranged from 95 to 106%, implying the great potential of the presented aptasensor in food product analysis.