A high-performance PEDOT:PSS platform electrochemical biosensor for the determination of HER2 based on carboxyl-functionalized MWCNTs and ARGET ATRP

Abstract

Human epidermal growth factor receptor 2 (HER2) is an important breast cancer marker that is abnormally expressed in 20–30% of breast cancer patients. Here, we report an electrochemical biosensor using carboxy-functionalized multi-walled carbon nanotubes (MWCNTs) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) on a highly conductive poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) platform for efficient detection of HER2. In this work, PEDOT:PSS and AuNPs were first modified onto a glassy carbon electrode (GCE) to increase the signal transmission efficiency of the biosensor. Then, an aptamer-HER2-antibody (Apt-HER2-Ab*) sandwich structure was constructed to capture and immobilize the target HER2. Of note, the Ab* is a composite composed of Ab, poly ferrocene methyl methacrylate (PFMMA), and carboxyl-functionalized MWCNTs (Ab-MWCNTs-PFMMA). The BMP was attached to the electrode by forming an ester bond with the hydroxyl group on the carboxyl-functionalized MWCNTs, and triggering ARGET ATRP to attach FMMA to the MWCNTs. In addition, Ab was attached to the electrode by ester bonds with the MWCNTs. In the presence of highly conductive materials and a polymer, the biosensor showed high sensitivity and a good linear relationship between the current signal and HER2 concentration in the range of 10⁻² to 10³ ng mL⁻¹, and the limit of detection (LOD) was 1.979 fg mL⁻¹. The regression equation was I (μA) = 8.23905 lg[C_HER2/ng mL⁻¹] + 25.3585 (R² = 0.995). Moreover, the biosensor still shows good detection performance in the complex environment of normal serum, which is promising for clinical applications.