A three-site recognition cytosensor for accurate detection of circulating tumor cells based on novel branched Pt Au nanospheres and MnO-GO-Au nanosheets.

A novel electrochemical cytosensor was developed with a three-protein recognition strategy, employing branched Pt Au nanospheres (B-Pt-Au NPs) as tags and MnO-GO-Au nanosheet-modified electrodes for circulating tumor cells (CTC) detection. This system integrates specific magnetic separation and CTC enrichment with sensitive electrochemical detection to identify rare A549 cells in whole blood. MnO-GO-Au nanosheets, known for their high conductivity and biocompatibility, were used to modify a bare electrode, improving the electrochemical interface for biomolecules. The B-Pt-Au NPs could only approach the sensing interface and enhance the current signal through their specific electrocatalytic activity when all three specific proteins, i.e. mucin 1 (MUC1), epithelial cell adhesion molecule (EpCAM), and epidermal growth factor receptor (EGFR), of rare A549 cells in peripheral blood were simultaneously expressed on the cell membrane. The developed cytosensor demonstrated a detection limit as low as 1 cell mL⁻ and, more importantly, could accurately distinguish A549 cells from other cancer cells. Thus, this proposed strategy offers a powerful tool for liquid biopsy analysis of extremely rare CTCs in complex peripheral blood, with potential applications in reliable early diagnosis of non-small cell lung cancer (NSCLC).