A multicolor time-resolved fluorescence aptasensor for the simultaneous detection of multiplex Staphylococcus aureus enterotoxins in the milk

Food safety is one of the most important public health issues worldwide. Foodborne illnesses caused by Staphylococcus aureus enterotoxins (SEs) commonly occur, affecting both developing and developed countries. In this study, multicolor lanthanide-doped time-resolved fluorescence nanoparticles labeled with aptamers were used as bioprobes, and graphene oxide (GO) was employed as a resonance energy acceptor. Based on the "turn down" strategy, the simultaneous detection of multiplex SEs was realized in a homogeneous solution. Under the optimal conditions, the developed method exhibited high sensitivity and selectivity to three serological types of enterotoxins, including type A, B, C1, with limits of detection below 1 ng mL(-1). The application of this bioassay in milk analysis with no sample dilution was also investigated, and the results of recovery rates covered from 92.76% to 114.58%, revealing that the developed method was accurate. Therefore, this detection aptasnesor can be a good candidate for multiplex analysis and screening with simple and effective operations.