In clinical and biological fields, circulating tumor cells (CTCs) attracts much attention for the valuable information about cancer progression, cancer status, and prognosis after the treatment with metastatic cancer. Recently, many researchers have studied to count CTCs efficiently. Representative methods of CTC detection are the immune-reaction based method and the morphology-based method. However, the immune-reaction based method is weak due to the imperfect markers, and morphology-based method has a defect because of the unclear criterion. In this paper, we described the CTC detection system based on flow cytometry technique with morphology and immune reaction based methods. The size and the immune-reaction information can be simultaneously obtained from DC impedance based detection and fluorescence detection, respectively. The performance of our system was evaluated with fluorescence beads. To apply the proposed system to biological samples, the human ovarian cancer cell lines (OVCAR-3) suspended in phosphate buffered saline (PBS) were tested. OVCAR-3 cells were stained by fluorescence tagged anti-epithelial cancer adhesion molecule (EpCAM). The portable flow cytometer system could detect the cancer cells with these methods. The proposed system has sufficient potential for point-of-care testing type cancer cell counter and many valuable clinical applications in the near future.
We reports on a novel microfluidic chip with polyelectrolytic gel electrodes (PGEs) used to rapidly count the number of
red blood cells in diluted whole blood. The number and amplitude of dc impedance peaks provide the information about
the number and size of red blood cells, respectively. This system features a low-voltage dc detection method and noncontact
condition between cells and metal electrodes. The performance of this PGEs-based system was evaluated in three
steps. First, in order to observe the size-only dependence of the impedance signal, three different sizes of fluorescent
microbeads were used in the experiment. Second, the cell counting performance was evaluated by using 7.2 μm
fluorescent microbeads, similar in size to red blood cells, in various concentrations and comparing the results with an
animal hematoanalyzer. Finally, in human blood sample tests, intravenously collected whole blood was just diluted in a
phosphate buffered saline without centrifuge or other pretreatments. The PGEs-based system produced almost identical
numbers of red blood cells in over 800-fold diluted samples to the results from a commercialized human hematoanalyzer.