A "signal off" aptasensor based on NiFe2O4 NTs and Au@Pt NRs for the detection of deoxynivalenol via voltammetry.

A "signal off" aptasensor has been developed to detect deoxynivalenol (DON). DON aptamers (Apt) were used as biological recognition elements, nickel ferrite nanotubes (NiFe2O4 NTs) are used as the base material to increase the surface area of the electrode, and the Au@Pt NRs were used as carriers for loading signal labels thionine (Thi) and complementary strand (cDNA). In the presence of DON it will be specifically captured by Apt, then the competition mechanism was triggered; the signal molecules fall off from the electrode surface, which then causes the electrode signal to decrease. NiFe2O4 NTs and Au@Pt NRs were characterized by transmission electron microscope (TEM), scanning electron micrograph (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The designed sensor provides a concentration range of 1 × 10-8 to 5 × 10-4 mg mL-1 and limit of detection of 3.02 × 10-9 mg mL-1. Determination of DON in corn meal samples was investigated and the recovery was 98.4 to 103.5%. The proposed aptasensor displayed good sensitivity, high specificity, and acceptable reproducibility. Graphical abstract Based on NiFe2O4 NTs as substrate material and Au@Pt NRs as signal label prepared DON aptasensor for the determination of DON.