Composite Films of CdS Nanoparticles, MoS2 Nanoflakes, Reduced Graphene Oxide, and Carbon Nanotubes for Ratiometric and Modular Immunosensing-Based Detection of Toxins in Cereals

Many kinds of mycotoxins can be found in cereals and feeds, thus increasing food safety requires effective and simultaneous detection of multitoxins. Herein, a flexible and three-dimensional (3D) film from CdS nanoparticles/MoS2 nanoflakes/reduced graphene oxide/carbon nanotubes (CMGC) nanocomposites was synthesized and pasted on various substrates including FTO, ITO, and glass carbon electrode (GCE) as the immunosensor substrate. By decorating the film electrode with different antigens, we built a modularity immuosensor using a ratiometric signal from photoelectrochemical (PEC) and cyclic voltammetric (CV) response, thus a universal standard curve was established to detect ochratoxin A (OTA), aflatoxin B1 (AFB1) and zearalenone (ZEN). In addition, such a tape-pasted electrode was removable and renewable, which can be used to detect toxins in cereals with high sensitivity and accuracy. We believe that such a detection of OTA, AFB1, and ZEN from modularity and ratiometry can offer alternative strategies of the immunosensor in multicomponent detection.