A Polyamidoamine Dendrimer-Based Electrochemical Immunosensor for Label-Free Determination of Epithelial Cell Adhesion Molecule- Expressing Cancer Cells

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 8; p. 1879
• Main Authors: Xu, Jianguo, Wang, Xinxin, Yan, Chao, Chen, Wei
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 19.04.2019; MDPI AG
• Subjects: epithelial cell adhesion molecule (EpCAM), electrochemical impedance spectroscopy (EIS); immunosensor; label-free; polyamidoamine dendrimer; immunosensor; polyamidoamine dendrimer; label-free; epithelial cell adhesion molecule (EpCAM), electrochemical impedance spectroscopy (EIS)
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19081879

A new electrochemical immunosensor for cancer cell detection based on a specific interaction between the metastasis-related antigen of epithelial cell adhesion molecule (EpCAM) on the cell membrane and its monoclonal antibody (Anti-EpCAM) immobilized on a gold electrode has been developed. The amino-terminated polyamidoamine dendrimer (G6 PAMAM) was first covalently attached to the 3-mercaptopropionic acid (MPA)-functionalized gold electrode to obtain a thin film, and then completely carboxylated by succinic anhydride (SA). Next, the Anti-EpCAM was covalently bound with the G6 PAMAM to obtain a stable recognition layer. In the presence of the EpCAM expressing hepatocellular carcinomas cell line of HepG2, the specific immune recognition (Anti-EpCAM/EpCAM) led to an obvious change of the electron transfer ability. The properties of the layer-by-layer assembly process was examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The final determination of HepG2 cells was performed in the presence of the reversible [Fe(CN) ] redox couple using impedance technique. Based on the advantages of PAMAM nanomaterial and immune reaction, a linear response to HepG2 cells ranging from 1 × 10 to 1 × 10 cells mL with a calculated detection limit of 2.1 × 10 cells mL was obtained. We expect this method can provide a potential tool for cancer cell monitoring and protein expression analysis.