Electrochemical immunosensor for IL-13 Receptor α2 determination and discrimination of metastatic colon cancer cells.

This work describes the first electrochemical immunosensor reported for the determination of IL-13 receptor Rα2 (IL-13Rα2), an emerging relevant biomarker in metastatic colon cancer. The approach involves the formation of sandwich immunocomplexes using specific capture (CAb) and biotinylated detector antibodies (BDAb) further labeled with an streptavidin-horseradish peroxidase (Strep-HRP) polymer, onto carboxylic acid-modified magnetic microbeads (HOOC-MBs). Amperometric detection at disposable carbon screen-printed electrodes (SPCEs) using the (H2 O2 )/hydroquinone (HQ) system was employed to monitor the affinity reactions. The developed immunosensor exhibits a linear calibration plot over the 3.9-100 ng mL-1 concentration range, a LOD of 1.2 ng mL-1 and excellent selectivity against other non-target proteins. The amperometric immunosensor was applied successfully to quantify for the first time the IL-13Rα2 expression in raw lysates of colon cancer cells and to discriminate the metastatic potential of intact cells through recognition of this target extracellular receptor. In comparison with the commercial Enzyme-Linked ImmunoSorbent Assay (ELISA) kit involving the same immunoreagents, the immunosensor provides a similar LOD in a half-time for the assay.