Detection and isolation of free cancer cells from ascites and peritoneal lavages using optically induced electrokinetics (OEK).

Detection of free gastric cancer cells in peritoneal lavages and ascites plays a vital role in gastric cancer. However, due to the low content of cancer cells in patients' peritoneal lavages, traditional detection methods lack sensitivity and cannot satisfy clinical demand. In this study, we used an optically induced electrokinetics (OEK) microfluidic method for label-free separation and characterization of patient gastric cancer cells. This method showed high effectiveness and sensitivity. We successfully separated cancer cells from a simulated peritoneal lavage mixture of gastric cancer cell lines and peritoneal lavage cells in a ratio of 1:1000. We further separated gastric cancer cells from six patients' ascites with purity up to 71%. In addition, we measured the cell membrane capacitances, which may be used as a biomarker for gastric cancer cells. Thus, our method can be used to effectively and rapidly detect peritoneal metastasis and to acquire cellular electrical information.