A fluorescent aptasensor based on nitrogen-doped carbon supported palladium and exonuclease III-assisted signal amplification for sensitive detection of AFB1

Abstract

Aflatoxin B1 (AFB₁) has strong carcinogenicity and toxicity, so it is necessary to develop a highly sensitive detection method. In this paper, a novel nitrogen-doped carbon supported palladium (C-N-Pd) material was synthesized and firstly used as the energy receptor for fluorescent aptasensor. Using C-N-Pd as a novel quenching material and exonuclease Ⅲ (Exo III) as assisted signal amplification, a fluorescent aptasensor for AFB₁ detection was constructed. Compared with the sensor without enzyme, the fluorescence intensity obtained by the sensor with Exo III increased by 74.7%. The fabricated fluorescent aptasensor exhibited a good selectivity toward AFB₁ with a limit of detection (LOD) as low as 9 pg mL^-1. Moreover, the designed aptasensor was successfully utilized to detect AFB₁ in spiked corn, peanut and wine samples, and the LOD is 15 pg mL^-1, 13 pg mL^-1 and 18 pg mL^-1, respectively. In addition, the aptasensor was also compared with HPLC method, and the good agreement was found between them.

Keywords: Exonuclease Ⅲ; Fluorescent aptasensor; Nitrogen doped carbon supported palladium; Signal amplification.