A Novel Ochratoxin A Aptasensor Based on Three-Dimensionally Ordered Macroporous RGO-AuNPs-MoS2 Enhanced Electrocatalysis of Methylene Blue and AuNPs-Fe3O4@C Composite as Signal Probe Carrier

In this work, a novel electrochemical aptasensor for the detection of ochratoxin A (OTA) was developed using three-dimensionally ordered macroporous (3DOM) reduced graphene oxide–Au nanoparticles–molybdenum disulfide (RGO-AuNPs-MoS2) composite material as sensing interface and Au nanoparticles–carbon-coated ferroferric oxide (AuNPs-Fe3O4@C) signal amplifier. The 3DOM RGO-AuNPs-MoS2 exhibited excellent conductivity catalytic activity. film electrodeposited onto electrode surface to immobilize DNA capture probe (CP), which then hybridized with helper strands (HS) OTA aptamer (OPT) form Y-shaped structure. presence OTA, OPT released from combined AuNPs-Fe3O4@C containing DNA1-metheylene blue (S1-MB) DNA2-metheylene (S2-MB). current response coming MB proportional concentration. Under optimal conditions, linear range 1 fg/mL 0.1 μg/mL, limit low 0.56 fg/mL. also used detect in rice wheat samples, results were agreement those obtained by liquid chromatography-mass spectrometry (HPLC-MS).