▎ 摘　　要

Assessment of human epidermal growth factor receptor-2 (HER2) tumor marker status is an impressive factor in screening, diagnosing and monitoring breast cancer (BC). The electrochemical biosensor is a revolutionary method in cancer diagnosis, which is used in this research to detect HER2(+) circulating tumor cells. The electrochemical activity, size, shape, and morphology of the synthesized nanomaterials were analyzed. The hybrid nanocomposite established by the coupling of reduced graphene oxide nanosheets (rGONs) and rhodium nanoparticles (Rh-NPs) on the surface of graphite electrode resulted in improved surface area, electrochemical activity, and biocompatibility. The graphite electrode-based aptasensor (g-aptasensor) demonstrated exceptional performance against HER2-overexpressed SKBR3 cancer cells, with a linear dynamic range of 5.0 to 10.0 x 10(4) cells/mL, an analytical limit of detection (LOD) as low as 1.0 cell/mL, and a limit of quantification (LOQ) of 3.0 cells/mL. The G-rich DNA aptamers can fold into an intermolecular G-quadruplex, which specifically bind to the target molecule. Consequently, the advantages of this highly efficient nanocomposite platform include broad dynamic range, high specificity, selectivity, stability, reproducibility, and low cost. These characteristics indicate that the fabricated nanobiosensor has a high potential for use in detecting and monitoring HER2 level for the care of BC patients and clinical diagnosis.