A fluorescence and surface-enhanced Raman scattering dual-mode aptasensor for sensitive detection of deoxynivalenol based on gold nanoclusters and silver nanoparticles modified metal-polydopamine framework.

Deoxynivalenol (DON), a common mycotoxin produced by Fusarium species, poses a great threat to human and animal body. Hence, it is of significance to develop an ultrasensitive and reliable method for DON detection. Herein, a fluorescence and surface-enhanced Raman scattering (FL-SERS) dual-mode aptasensor was designed for the detection of DON based on gold nanoclusters (Au NCs) and silver nanoparticles modified metal-polydopamine framework (Ag NPs/MPDA). In this aptasensor, complementary DNA modified Au NCs (cDNA-Au NCs) was selected as fluorescence probe, and 6-carboxytetramethylrhodamine (TAMRA)-labeled aptamer modified Ag NPs/MPDA (Ag NPs/MPDA-Apt-TAMRA) was employed as SERS probe, in which Ag NPs/MPDA acted as SERS substance and fluorescence quencher, and TAMRA acted as Raman label. The superior binding affinity of the aptamer with DON to cDNA can regulate the fluorescence and Raman signal intensities and realize the quantitative determination of DON. Under the optimal conditions, the aptasensor exhibited a low detection limit of 0.08 ng mL (0.1-100 ng mL) in FL mode and 0.06 ng mL (0.1-100 ng mL) in SERS mode. In addition, it was successfully applied for DON detection in wheat flour. We believe that the proposed FL-SERS strategy has a promising application in the detection of mycotoxins.