Determination of EGFR-overexpressing tumor cells by magnetic gold-decorated graphene oxide nanocomposites based impedance sensor.

This work developed an electrochemical impedance spectroscopy (EIS) sensor for detection of EGFR (epidermal growth factor receptor)-overexpressing tumor cell and preliminary estimation of EGFR expression. Here, EGFR antibodies as the specific antibodies for cancer cells were conjugated on magnetic gold-decorated graphene oxide nanocomposites, which were used to capture the EGFR-overexpressing tumor cells. The magnetically responsive tumor cells were enriched and immobilized on a magnetic glassy carbon electrode (mGCE) surface, leading to increased electron-transfer resistance (R) utilized for determination of cells and preliminary evaluation of EGFR expression level. This strategy enables the enrichment, fixation and detection of tumor cells to be accomplished in a facile way. An excellent linearity in the range of 2.0 × 10 - 3.0 × 10 cell mL with the detection limit of 152 cell mL for MDA-MB-231 cells was obtained. Investigation on the expression levels of EGFR on various types of cells was conducted. MDA-MB-231 cells showed a distinctly higher EGFR expression, compared with MHCC97-L and L02 cells, providing the possibility for the EGFR-targeted therapy of the tumors. It is expected that the proposed sensor has the potential to be applied for cancer monitoring.