Amperometric immunosensor for the determination of ceruloplasmin in human serum and urine based on covalent binding to carbon nanotubes-modified screen-printed electrodes

• The development of an amperometric immunosensor for ceruloplasmin is reported for the first time.
• The immunosensing approach involves indirect competitive immunoassay based on Cp immobilization on carbon nanotubes-modified screen printed electrodes.
• The developed design exhibits excellent sensitivity, detection limit, selectivity, wide range of quantifiable antigen concentrations and reproducibility.
• It can be envisaged as a useful analytical tool for the rapid determination of Cp in clinical samples.

A novel electrochemical immunosensor for the determination of ceruloplasmin (Cp) in human serum and urine is reported. The immunosensor configuration involves an indirect competitive immunoassay implying covalent immobilization of Cp on activated carboxylic groups at carbon nanotubes-modified screen-printed electrodes (CNTs/SPE). After Cp immobilization and reaction between the target analyte and anti-ceruloplasmin antibodies in solution, the remaining non-conjugated antibody is attached on the Cp-CNTs modified electrode. Monitoring of Cp is performed by means of a secondary antibody labeled with peroxidase (HRP-anti-IgG) and measurement of the amperometric current resulting from the addition of hydrogen peroxide in the presence of hydroquinone as the redox mediator. The experimental variables affecting the analytical performance of the immunosensor were optimized. Calibration curves for Cp provided a linear range between 0.07 and 250 μg/mL (r=0.997). The limit of detection achieved was 21 ng/mL. These analytical characteristics allow the immunosensor to be successfully used for the determination of Cp in spiked human serum and urine at various concentration levels.