Bifunctional carbon nanodots for highly sensitive HER2 determination based on electrochemiluminescence

Abstract Early detection of breast cancer increases the chances of achieving adequate and successful treatment as soon as possible. In this work, a promising disposable electrochemiluminescent immunosensor has been developed for simple, efficient detection of the HER2 protein, a breast cancer biomarker. Nitrogen-rich carbon nanodots were synthesized with two functions: to provide functional groups for covalent immobilization of HER2 antibodies and to act as co-reactants in the electrochemiluminescent process. The proposed immunosensor responded linearly to HER2 concentration over a wide range, showing a detection limit of 20.4 pg mL−1. The reliability of this biosensor was confirmed by analyzing HER2 in the presence of another tumor biomarker (CEA), as well as various proteins and sugars. In addition, this proposed strategy presented good stability and applicability in the analysis of human serum samples, showing great potential for applications in the early diagnosis of breast cancer.