Horseradish peroxidase assisted "signal-on" chemiluminescence aptasensor for sensitive detection of aflatoxin B1

Aflatoxin B1 (AFB1) analysis is crucial in food safety, environmental monitoring, and quality control. We developed a "signal-on" chemiluminescence aptasensor by using horseradish peroxidase (HRP)-labeled aptamer as affinity ligand, enabling the sensitive detection of AFB1. Complementary DNA (cDNA) of aptamer was immobilized on magnetic beads, and AFB1 in sample solution competed with cDNA coated on magnetic beads to bind to the HRP-labeled aptamer probe. The resulting AFB1-aptamer complexes were then magnetically separated and used for catalyzing substrate to produce chemiluminescence signals. Specifically, higher concentrations of AFB1 led to more AFB1-aptamer complexes being separated, thereby generating stronger chemiluminescence signals. Benefiting from the high catalytic activity of HRP for signal amplification and the advantages of chemiluminescence detection, this assay demonstrated high sensitivity to AFB1, with the detection limit of 0.01 nM. The dynamic range spanned from 0.01 nM to 500 nM, covering more than four orders of magnitude. The assay exhibited good selectivity and was successfully applied to detect AFB1 in diluted beer, liquor, and red wine samples. By leveraging the merits of aptamer, including high stability, good reproducibility, and facile chemical synthesis, this aptasensor holds great potential for practical AFB1 detection.