Dual-channel ITO-microfluidic electrochemical immunosensor for simultaneous detection of two mycotoxins

Due to the widely occurring co-contamination of mycotoxins in raw food materials, simultaneous monitoring of multiple mycotoxins is needed. Herein, we report the design and fabrication of an electrochemical immunosensor for simultaneous detection of two mycotoxins, fumonisin B1 (FBi) and deoxynivalenol (DON), in a single test. A dual-channel three-electrode electrochemical sensor pattern was etched on a transparent indium tin oxide (ITO)-coated glass via photolithography and was integrated with capillary-driven polydimethylsiloxane (PDMS) microfluidic channel. The two working electrodes were functionalized with gold nanoparticles and anti-FBi and anti-DON antibodies. Tests were performed by incubating the working electrodes in a sample solution introduced in the PDMS channel. The formation of toxin-antibody immunocomplexes on the working electrode surface produced electrochemical signal responses, which were recorded and compared with control signal to quantify individual mycotoxin concentrations. Using this dual-channel ITO-microfluidic electrochemical immunosensor we achieved limits of detection (LODs) of 97 pg/mL and 35 pg/mL, respectively for FBi and DON, and their corresponding linear ranges of detection were 0.3-140 ppb and 0.2-60 ppb. The sensor performance, which remained stable for two weeks under proper storage, was validated by testing with ground corn extract used as a real food matrix.