As a significant food safety risk factor linked to cancer, liver diseases, and kidney diseases, aflatoxin B1 (AFB1) necessitates rapid and ultrasensitive detection to mitigate its associated high morbidity and mortality rates. In this study, we developed an advanced biosensor for AFB1 detection by optimizing magnetic nanoparticles (MNPs), platinum nanoparticles (PtNPs), and aptazymes. The resulting MNPs-aptazymes-PtNPs molecular motor biosensor demonstrates promising capabilities for AFB1 detection. Initially, the specific binding between AFB1 and a split aptamer pair facilitates the conversion of intermolecular hybridization of DNAzyme strands into intramolecular hybridization on the MNPs surface. Then the catalytic strands of DNAzyme cleave substrate strands, resulting in PtNPs-containing fragments being released from the MNPs surface and enabling the molecular motor’s movement. The extensive cleavage of substrate strands by the long catalytic strands and the stepwise movement on MNPs surface are driven by the target-specific binding of AFB1. With high peroxidase-mimicking activity, the released PtNPs enable AFB1 detection after short incubation period. The MNPs-aptazymes-PtNPs molecular motor exhibits a sensitivity of 98.95 % and a specificity of 100 %, with a minimum detectable concentration of 300 fg/mL. This thermostabilized, cyclic, and enzyme-free nanomachine demonstrates broad applicability for the detection of various aflatoxins due to its target-empowered, sequence-independent mechanism, possesses excellent guarantee and supervision for enormous Ganoderma products in Shandong province, China.
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