A sandwich-type electrochemical immunosensor for sensitive detection of HER2 based on dual signal amplification of La-MOF-PbO and PEI-MoSNFs composites.

In recent decades, the incidence of breast cancer has increased year by year, posing a serious threat to human health and quality of life, and about 30% of breast cancer patients have human epidermal growth factor receptor 2 (HER2) overexpression. Therefore, HER2 has become an important biomarker and indicator for the clinical evaluation of breast cancer in diagnosis, prognosis and recurrence. In this work, polyethyleneimine functionalized MoS nanoflowers (PEI-MoSNFs) with good electrical conductivity and abundant active binding sites were designed and employed as a sensing platform for immobilizing the primary antibody of HER2 (Ab). In addition, a La-MOF-PbO composite with a large specific surface area and good conductivity was used to load lots of electroactive toluidine blue (TB) and the secondary antibody of HER2 (Ab) via gold nanoparticles (AuNPs) as the linker. Thus, the constructed sandwich-type electrochemical immunosensor was applied for sensitive detection of HER2, which showed a wide linear range from 100 fg mL to 10 μg mL with a lower limit of detection of 15.64 fg mL. Therefore, the resulting immunosensor in this study would have a potential application in clinical bioanalysis.