Biosensing Strategy for Simultaneous and Accurate Quantitative Analysis of Mycotoxins in Food Samples Using Unmodified Graphene Micromotors.

A high-performance graphene-based micromotor strategy for simultaneous, fast, and reliable assessment of two highly concerning mycotoxins (fumonisin B1 (FB1) and ocratoxin A (OTA)) has successfully been developed. The assay principle is based on the selective recognition from aptamers to the target mycotoxins and further "on-the-move" fluorescence quenching of the free aptamer in the outer layer of unmodified reduced graphene (rGO; sensing layer) micromotors. Template-prepared rGO/platinum nanoparticles (PtNPs) tubular micromotors were synthesized rapidly and inexpensively by the direct electrodeposition within the conical pores of a polycarbonate template membrane. The new wash-free approach offers using just 1 μL of sample, a simultaneous and rapid "on-the-fly" detection (2 min) with high sensitivity (limits of detection of 7 and 0.4 ng/mL for OTA and FB1, respectively), and high selectivity. Remarkable accuracy (E < 5%) during the mycotoxin determination in certified reference material as well as excellent quantitative recoveries (96-98%) during the analysis of food samples were also obtained. The excellent results obtained allow envisioning an exciting future for the development of novel applications of catalytic micromotors in unexplored fields such as food safety diagnosis.