Electrochemical capacitance-based aptasensor for HER2 detection.

The overexpression of Human Epidermal Growth Factor Receptor 2 (HER2) protein is specifically related to tumor cell proliferation in breast cancers. Its presence in biological serum samples indicates presence or progression of cancer, becoming a promise biomarker. However, their detection needs a simple and high accuracy platform. In this study, we report the develop and optimization of a simple highly sensitive electrochemical platform for HER2. Gold electrode surface was modified with a self-assembled monolayer composed by DNA aptamer, 6-(ferrocenyl) hexanethiol and 6-mercapto-1-hexanethiol. Electrochemical impedance spectroscopy was used to quantify the changes in capacitance on the interface due to the presence ferrocene, whether acting as a redox charge or its behavior under different HER2 concentration in PBS and undiluted human serum. As a result, the approach allows detection of HER2 with a limit of detection of 3.61 pg/mL, 12.28 nF sensitivity per decade and a linear range from 1 pM to 1 [Formula: see text]M in serum. This electrochemical aptasensor can be applied to different arrays for aptamer screening and has a significant importance to interaction study of biological systems.