Graphene quantum dots-functionalized multi-walled carbon nanotubes as nanocarriers in electrochemical immunosensing. Determination of IL-13 receptor α2 in colorectal cells and tumor tissues with different metastatic potential

Abstract

In this work, the development of the first integrated electrochemical immunosensor for the determination of the IL-13Rα2 is reported. The strategy involves the immobilization of a biotinylated capture antibody onto streptavidin-modified screen-printed electrodes through grafting with p-aminobezoic acid (p-ABA) and further activation using EDC/Sulfo-NHS chemistry. A hybrid nanomaterial composed of multiwalled carbon nanotubes (MWCNTs) and Graphene Quantum Dots (GQDs) was used as nanocarrier of multiple detector antibody and HRP molecules. Amperometric detection with the system H2O2/hydroquinone (HQ) achieved a linear calibration plot ranging from 2.7 to 100 ng mL−1 IL-13sRα2, with a LOD value of 0.8 ng mL−1. The immunosensor showed an excellent selectivity and was successfully applied to the determination of the target receptor directly in small amounts of raw cellular lysates and extracts of paraffin-embedded tissues from patients diagnosed with colorectal cancer at different stages.