Graphene oxide quantum dots based nanotree illuminates AFB1: Dual signal amplified aptasensor detection AFB1

Aflatoxin B1 (AFB1) is the most toxic metabolite of mycotoxins and constantly contaminates food crops, which seriously endangers human health. Therefore, it is essential to explore a rapid and sensitive method for AFB1 detection. Herein, a fluorescence aptasensor based on DNA walker, DNA tetrahedron nanostructures (DTNs) and network hybridization chain reaction (HCR) for monitoring AFB1 was proposed. DNA walker structure was employed as signal amplifier induced by targets AFB1 where DNA walker chain could walk on a three-dimensional track of gold nanoparticles (AuNPs) and combine complementary sequences of DTNs, triggering the cutting of endonuclease and releasing a lot of DTNs. DTNs were fabricated by four single-stranded DNA, which have multiple fulcrums. DTNs provided multiple reaction orientations for HCR and improved the assembly rate of graphene oxide quantum dots (GQDs) based nanotree. In presence of target AFB1, target AFB1 would bind with aptamers and trigger secondary signal amplification to achieve sensitive detection. This aptasensor could sensitively detect AFB1 in a linear range of 1−1000 pg/mL with a detection limit as low as 0.492 pg/mL. In addition, this method can also be employed in monitoring other hazardous substances.