Dimanganese trioxide (Mn₂O₃) based label-free electrochemical biosensor for detection of Aflatoxin-B1

This work presents, a manganese oxide nanoparticles (Mn₂O₃nps) based electrochemical immunosensor for the detection of Aflatoxin-B1 (AFB1). X-ray diffrraction spectroscopy study confirms the purely synthesized Mn₂O₃nps with an average crystallite size of 31.5 nm. Transmission electron microscopy study confirms average particle size of 45 nm. To fabricate an electrochemical biosensor, a thin film of Mn₂O₃nps was fabricated onto indium tin oxide (ITO) surface using electrophoretic technique. Such fabricated thin film was utilized to immobilize antibodies (Anti-AFB1) for the selective detection of AFB1 using differential pulse voltammetry technique. Prior to perform sensing, bovine serum albumin (BSA) was utilized to block the uncovered sites on the Anti-AFB1/Mn₂O₃/ITO immunoelectrode surface. The response of BSA/Anti-AFB1/Mn₂O₃/ITO immunoelectrode was measured as a function of AFB1 in a linear detection range of 1 pg mL^-1 to 10 µg mL^-1 and sensor showed highest sensitivity of 2.044 μA mL ng^-1cm^-2 with lower detection limit of 0.54 pg mL^-1. A spiked sample response of corn extract was studied in the linear range of 1 pg mL^-1 to 10 µg mL^-1 and immunoelectrode (BSA/Anti-AFB1/Mn₂O₃/ITO) showed recovery rate of 98.6 %.