A highly efficient rare earth metal oxide nanorods based platform for aflatoxin detection

Abstract

The nanostructured rare earth metal oxide (samarium oxide, n-Sm₂O₃) nanorods, prepared using a forced hydrolysis technique, have been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. This novel platform has been utilized for co-immobilization of monoclonal antibodies of aflatoxin B₁ (Ab-AFB₁) and bovine serum albumin (BSA) via electrostatic interactions for food toxin (AFB₁) detection. Thus prepared n-Sm₂O₃ nanorods have been characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. The results of electrochemical response studies of the BSA/Ab-AFB₁/n-Sm₂O₃/ITO immunoelectrode obtained as a function of aflatoxin concentration reveal a linearity of 10–700 pg mL⁻¹, a detection limit of 57.82 pg mL⁻¹ cm⁻², a response time of 5 s and a sensitivity of 48.39 μA pg⁻¹ mL⁻¹ cm⁻² with a regression coefficient of 0.961. The association constant (K_a) for antigen–antibody interactions obtained is 47.9 pg mL⁻¹, which indicates high affinity of antibodies towards the antigen (AFB₁). The application of n-Sm₂O₃ modified electrode for immunosensor analysis offers a novel platform and efficient strategy for the application of rare earth metal oxide materials in bioelectronics.