A novel sandwich aptasensor for detecting T-2 toxin based on rGO-TEPA-Au@Pt nanorods with a dual signal amplification strategy

T-2 toxin is a mycotoxin that can cause chronic illnesses, and the detection of T-2 toxin in food is critical for human health. Herein, a novel sandwich aptasensor with a dual signal amplification strategy was developed for the detection of T-2 toxin. Molybdenum disulfide-polyaniline-chitosan-gold nanoparticles (MoS 2 -PANI-Chi-Au) were processed to the modified glassy carbon electrode (GCE) and used as the aptasensor platform to expedite the electronics transport and immobilize the amino-terminated capture DNA probe by Au–N bonds. The reduced graphene oxide-tetraethylene pentamine-gold@platinum nanorods (rGO-TEPA-Au@Pt NRs) were first synthesized and immobilized with a signal DNA probe. Once T-2 toxin was added into the biosensing system, the aptamer would trap T-2 toxin to turn the signal off. Next, dissociative aptamer hybridized with the capture DNA probe in GCE and linked simultaneously to the signal DNA probe on rGO-TEPA-Au@Pt NRs with another end sequence of aptamer to turn the signal on. Owing to the efficient catalytic ability of bimetallic Au@Pt nanorods, the signal was perfectly amplified through the catalysis of hydrogen peroxide (H 2 O 2 ) and recorded by chronoamperometry. With the outstanding augment response, the limit of detection reached 1.79 fg mL −1 (3S B /m) and a wide linear range from 10 fg mL −1 to 100 ng mL −1 was presented. The sensitivity of the aptasensor was 19.88 μA⋅μM −1 ⋅cm −2 . Meanwhile, the DNA aptamer-bimetallic nanorod based sensing system presented excellent specificity. The developed aptasensor provides a new platform for T-2 toxin detection with low cost for real sample assays. • Aptasensor based on target-triggering competition strategy was first used for the trace detection of T-2 toxin. • rGO-TEPA-Au@Pt NRs composite was applied to the dual signal amplification. • The cleavage of anti-aptamer DNA sequence offered a new thought for the detection of micromolecule. • The aptamer and T-2 toxin recognition proceed in the microtubes avoiding the electrode surface area limitation.