Graphene-manganese dioxide based aptasensor for highly sensitive detection of Ochratoxin A

Abstract. Biosensors have recently emerged as a simpler and cheaper alternative to traditional methods like HPLC for detecting ochratoxin A (OTA). This study aims to design a highly sensitive and selective aptasensor using graphene oxide (GO) and manganese dioxide nanoparticles (MnO₂NPs). The aptasensor, made with screen-printed carbon electrode (SPCE), was fabricated using hydrothermally synthesized MnO₂NPs at concentrations of 0.2M, 0.3M, and 0.4M. electrochemical impedance spectroscopy (EIS) assessed the biosensor’s sensitivity, specificity, and selectivity, revealing a detection limit of 3.33 ng/mL for OTA. The aptasensor showed high selectivity for OTA even in the presence of other mycotoxins like aflatoxin B1 (AFB1), deoxynivalenol (DON), and zearalenone (ZEA) and effective detected OTA in spiked cocoa and oats. The fabrication of GO-MnO₂NPs helps in enhancing the aptasensor’s stability and performance due to their high surface area, biocompatibility, and excellent electrical conductivity. This study establishes the foundation for creating a functional, economical, and efficient biosensing system to detect OTA in food. The extensive implementation of such technology can significantly help improve food safety and safeguard consumer interests.