Visual detection of ochratoxin a based on GPE-PET bipolar electrode-electrochemiluminescence platform.

A GPE-PET (graphene-polyethylene terephthalate) bipolar electrode-electrochemiluminescence (BPE-ECL) platform was developed for ochratoxin A (OTA) detection. PET served as the electrode sheet substrate, and GPE was drop-coated onto the surface of PET to form a conductive line. On the functional sensing interface, the thiol (-SH) modified OTA aptamer (OTA-Aptamer) are fixed on the surface of the gold-plated cathode through AuS bonds. The efficient electron transfer ability of methylene blue (MB) made the anode ECL signal strong. Due to competition between OTA and MB with OTA-Aptamer, leading to a decrease in ECL intensity of the [Ru(bpy)]/TPA system on the BPE anode. Under optimized conditions, the GPE-PET BPE-ECL biosensor displayed superior sensitivity for OTA with a detection limit of 2 ng mL and a wide linear concentration range of 5-100 ng mL. This method could be further applied to detect various toxins and had broad application prospects.