Label-free cancer cell detection with impedimetric transducers

While cancer is still an implacable disease, many cancers can be cured if they are diagnosed in an early stage. Recently, it was reported that the transformation from normal cells to cancer cells can change their mechano-elastic properties to become softer and more deformable. If some cancer cells are more deformable, then a progressive increase of the volume of softer cancer cells should be induced as an abrupt change in osmolarity is applied. On the basis of this hypothesis, we developed a sensor that can electronically monitor the volume increase of cancer cells under hyposmotic pressure. By this methodology, K:Molv NIH 3T3 cells, 786-O human kidney carcinoma cells, and MPSC-1 ovarian cancer cells were successfully detected within 30 min using on the order of 10 cells. These cancer cells could be detected with the same sensitivity even in the presence of a vast excess of the respective noncancerous cells [NIH 3T3 cells, human embryonic kidney (HEK) 293 cells, ovarian surface epithelial (OSE) cells]. Since the proposed impedimetric sensor could be useful for detecting cancer cells fast and reliably, it could be further implemented in the screening of large populations of tissue samples and the detection of circulating tumor cells for point-of-care applications.