An Efficient Electrochemical Biosensor Based on Pencil Graphite Electrode Mediated by 2D Functionalized Graphene Oxide to Detect HER2 Breast Cancer Biomarker

Human epidermal growth factor receptor-2 (HER2) tumor marker is a known cancer biomarker and is widely used for diagnosis in clinical BrCa research. In this regard, our team has developed and operated a high selective electrochemical nano-biosensor for detection and quantification of the HER2 biomarker using a pencil graphite electrode mediated by two-dimensional (2D) functionalized graphene oxide (FGO). The unmodified and modified graphite electrodes were evaluated by different techniques, including imaging, spectroscopy, and electrochemistry. When FGO was synthesized by electrochemical oxidation and exfoliation on the graphite electrode surface and its electrochemical performance was measured, the results showed that the modified electrode had a better analytical efficiency. Due to the increase in electrical conductivity and surface area created by FGO on the graphite electrode surface, the sensitivity and electrochemical signal were amplified. The anti-HER2 aptamers were immobilized on the electrode surface through amide bonds, resulting in the binding of carboxyl groups to the FGO and amine groups to the end of the aptamer. Finally, the target HER2 biomarker was recognized. The modified electrode based on electrochemical aptasensing, illustrated a linear response for different concentrations of HER2 biomarker with a linear range from 0.5 ng/mL to 25 ng/mL, with a limit of detection (LOD) of 0.59 ng/ml without the need for any further amplification. The fabricated nano-biosensor showed good selectivity and stability under experimental conditions that could be used for accurate and rapid detection of HER2 biomarkers. This platform was also used for research and clinical studies, which had relatively good results.