Ultrasensitive label-free detection of circulating tumor cells using conductivity matching of two-dimensional semiconductor with cancer cell.

The excellent conductivity matching of two-dimensional (2D) semiconductor nanomaterials (e.g. MoS) with cancer cell plays an important role in ultrasensitive label-free impedimetric detection of circulating tumor cells (CTC) (<1 cell/mL). Firstly, 2D semiconductor materials (e.g. 2D MoS) exfoliated by folic acid (FA) is used to construct MoS/FA-modified gold electrode (AuE/MoS/FA). Then, the fabricated electrode is applied for HeLa cell detection in a linear range from 1 to 10 cell/mL with a detection limit of 0.43 cell/mL (S/N = 3). The detection mechanism of high sensitivity might be owing to the electric conductivity matching of MoS (0.14 S/m) to cancer cell (0.13-0.23 S/m). A negligible conductivity change induced by cancer cell will produce a large impedance change of semiconductor electrode. Furthermore, HeLa cells dispersed in healthy blood samples are detected by suggested cytosensor in a linear range from 50 to 10 cell/mL with a detection limit of 52.24 cell/mL (S/N = 2). Finally, we demonstrate that the cytosensor is capable of differentiating patients of cervical and liver cancers by the real CTC analysis from healthy control.