▎ 摘　　要

The ultrasensitive detection of human prostate metastatic cancer cells (Du-145) was investigated through a novel electrochemical cytosensor. The proposed biosensor was simultaneously developed via two approaches: multivalent identification and signal amplification. Herein, anti-CD166 monoclonal antibody-modified gold electrode was applied to capture and recognize target cells (Du-145). Also, a graphene (G)/gold nanoparticle (GNP)/horseradish peroxidase (HRP)-conjugated trastuzumab antibody (G/GNP/Ab-HRP) hybrid nanostructure was designed as a nanoprobe for accurate recognition of target cells and efficient amplification of enzymatic signals simultaneously. The performance of the cytosensor could be significantly improved by utilizing this novel signal-amplification strategy. The cytosensor described here exhibited an appropriate cell-capture ability, broad range of detection, and exceptional sensitivity with a low limit of detection (20 cells). The fabricated cytosensor showed high sensitivity and selectivity for detection of Du-145 cancer cells while keeping an extended linear range from 102 to 106 cells per ml, and a conveniently low limit of detection of 20 cells per ml. The extraordinary analytical performance of this cytosensor indicates that it has a great potential for the detection of cancer cells and cancer stem cells.