A label-free aptasensor for fluorescent detection of carbendazim based on a G-quadruplex-specific probe

Detection of carbendazim ( CZ) fungicide residues in food has received increasing attention in recent years. However, most reported methods are sophisticated, high cost, and low throughput. In this study, we designed a label-free fluorescent aptasensor for detecting CZ by using a G-quadruplex-specific probe. The anti-CZ aptamer could be partially complementary to the guanine (G)-rich sequence PW17 and block the formation of G-quadruplex structures, while not in the presence of CZ. The formed G-quadruplex structure in the presence of CZ could non-covalently bind to the fluorescent probe N-methyl mesoporphyrin IX (NMM) and activate its fluorescence. A linear relationship between fluorescence and CZ was obtained in the concentration range of 0.05-0.4 mu M with a detection limit of 24.28 nM. This study provides a new perspective for designing label-free aptasensors. [GRAPHICS] .