Improved electrochemical immunosensor for myeloperoxidase in human serum based on nanogold/cerium dioxide-BMIMPF6/L-Cysteine composite film

An electrochemical immunosensing assay for myeloperoxidase (MPO) determination in human serum has been developed. Firstly, L-Cysteine was initially electropolymerized on an Au electrode to form L-Cysteine film. After that cerium dioxide (CeO2) dispersed in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) were immobilized on the L-Cysteine film. Then the negatively charged nanogold particles were adsorbed onto the membrane via the positive charge of CeO2, which aimed at assembling more antibody of MPO (anti-MPO). The resulting immunosensor showed a high sensitivity, broad linear response to the MPO concentration comprised between 10 ng/mL and 400 ng/mL with a detection limit of 0.06 ng/mL. Moreover, the surface morphology of the electrode was studied by means of a scanning electron microscope and the electrochemical properties of the fabricated immunosensor were further characterized by cyclic voltammetry. Also, factors influencing the performance of the resulting immunosensors were studied in detail. (C) 2011 Elsevier B.V. All rights reserved.