Amperometric Immunosensor for Myeloperoxidase in Human Serum Based on a Multi-wall Carbon Nanotubes-Ionic Liquid-Cerium Dioxide Film-modified Electrode

A label-free amperometric immunosensor has been proposed for the detection of myeloperoxidase (MPO) in human serum To fabricate such an immunosensor, a composite film consisting of N,N-dimethylformamide (DMF), multi-wall carbon nanotubes (MWCNTs) and 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMIMBF4) suspension was initially formed on a glassy carbon electrode (GCE) Then cerium dioxide (CeO2) dispersed by chitosan was coated on the GCE After that, MPO antibodies (anti-MPO) were attached onto the nanoCeO(2) surface With a noncompetitive immunoassay format, the antibody-antigen complex formed between the immobilized anti-M PO and MPO in sample solution The immunosensor was characterized by cyclic voltammetry, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) The factors influencing the performance of the immunosensor were studied in detail Under optimal conditions, the current change before and after the immunoreaction was proportional to MPO concentration in the range of 5 to 300 ng mL(-1) with a detection limit of 0 2 ng mL(-1)