Nitrogen-enhanced carbon quantum dots mediated immunosensor for electrochemical detection of HER2 breast cancer biomarker

Using nitrogen-enhanced carbon quantum dots (N-CQDs) on a coated graphite sheet (GS) substrate (N-CQDs/ GS), a simple strategy for the electrochemical detection of human epidermal growth factor receptor 2 (HER2), a breast cancer biomarker, was investigated. The bovine serum albumin (BSA)-modified HER2 Antibody/N-CQDs/ GS immunoelectrode enabled excellent activity preservation for the biosensor, while the GS electrode provided a highly stable and conducting substrate. With a linear response range of 0.1 ng/mL-1 ng/mL and a low detection limit of 4.8 pg/mL. Meanwhile, the methodology demonstrated optimal specificity, stability, and reproducibility for detecting HER-2 protein in breast cancer patients untreated blood samples.