A disposable Protein A-based immunosensor for flow-injection assay with electrochemical detection Original Research Article

Low-cost disposable immunosensors were produced by covalent binding of Protein A or G on graphite-polystyrene screen-printed electrodes, and they were used in a fully automated flow-injection analysis (FIA) system, allowing the kinetics of IgG binding to Protein A or G to be improved by forced convection. The displacement of rabbit IgG bound to Protein A or G by mouse IgG isotypes (IgG1 or IgG2a) was studied. A FIA immunoassay of mouse IgG2a was performed at a Protein A-based immunosensor with a good sensibility (down to 0.02 μg ml−1) and a total assay time of 19 min. It was shown that the immunosensor combines the advantages of being reusable for more than 30 assay cycles in flow-injection analysis, and disposable when necessary.