A qPCR aptasensor for sensitive detection of aflatoxin M1

Aflatoxin M-1 (AFM(1)), one of the most toxic mycotoxins, imposes serious health hazards. AFM(1) had previously been classified as a group 2B carcinogen [1] and has been classified as a group 1 carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) [2]. Determination of AFM(1) thus plays an important role for quality control of food safety. In this work, a sensitive and reliable aptasensor was developed for the detection of AFM(1). The immobilization of aptamer through a strong interaction with biotin-streptavidin was used as a molecular recognition element, and its complementary ssDNA was employed as the template for a real-time quantitative polymerase chain reaction (RT-qPCR) amplification. Under optimized assay conditions, a linear relationship (ranging from 1.0 x 10(-4) to 1.0 mu g L-1) was achieved with a limit of detection (LOD) down to 0.03 ng L-1. In addition, the aptasensor developed here exhibits high selectivity for AFM(1) over other mycotoxins and small effects from cross-reaction with structural analogs. The method proposed here has been successfully applied to quantitative determination of AFM(1) in infant rice cereal and infant milk powder samples. Results demonstrated that the current approach is potentially useful for food safety analysis, and it could be extended to a large number of targets.