A system enabling isolation and electrical property characterization of circulating tumour cells

This paper presents a system capable of characterizing electrical property of circulating tumour cells (CTCs) based on microfluidic impedance spectroscopy. Following negative selection, which consisted of red blood cell (RBC) lysis and CD45 depletion, suspected CTCs were left behind. Using a capillary tube, cells were then transferred directly into the entrance of the microfluidic device, and aspirated into a constriction channel for the quantification of specific membrane capacitance (C_{specific membrane}) and cytoplasm conductivity (s_cytoplasm). Significant differences were found both in C_specificmembrane and s_cytoplasmamong CTCs isolated from patients suffering from hepatic (Cspecific membrane=2.26 ± 0.69 μF/cm²and s_cytoplasm=0.88 ± 0.43 S/m, n_cell=239), oral (1.82 ± 0.56 μF/cm²and 1.16 ± 0.49 S/m, n_cell=269) and lung (1.55 ± 0.35 μF/cm²and 1.39 ± 0.69 S/m, n_cell=468) cancers. These results validated the feasibility of the developed system, which may serve as a platform for the characterization of CTCs.