A nanostructured cerium oxide film-based immunosensor for mycotoxin detection

Abstract

Rabbit-immunoglobulin antibodies (r-IgGs) and bovine serum albumin (BSA) have been immobilized onto sol–gel-derived nanostructured cerium oxide (nanoCeO 2 ) film fabricated onto an indium–tin-oxide (ITO) coated glass plate to detect ochratoxin-A (OTA). Broad reflection planes obtained in x-ray diffraction (XRD) patterns reveal the formation of CeO 2 nanostructures. Electrochemical studies reveal that nanoCeO 2 particles provide an increased electroactive surface area for loading of r-IgGs with desired orientation, resulting in enhanced electron communication between r-IgGs and electrode. BSA/r-IgGs/nano CeO 2 /ITO immunoelectrode exhibits improved characteristics such as linear range (0.5–6 ng dl −1 ), low detection limit (0.25 ng dl −1 ), fast response time (30 s) and high sensitivity (1.27 µA ng −1 dl −1 cm −2 ). The high value of the association constant ( K a , 0.9 × 10 11 l mol −1 ) indicates the high affinity of the BSA/r-IgGs/nano CeO 2 /ITO immunoelectrode to OTA.