Circulating Tumor Cell Separation using Circular Reverse Wavy Channel: A Numerical Approach

Abstract

Early cancer detection is vital for the survival of a patient suffering from cancers of various types. A study done by the national census for the UK showed that the survival rates of patients suffering from Bowel, Breast, Lung, Ovary, Esophagus, Melanoma decreased from on average of 80% to below 30% for stage 3 cancer and more [1]. Current diagnosis techniques include fresh tissue biopsy, genome sequencing among others which are expensive, require operations to be performed on the patient and could take weeks for the results to arrive. The presence and concentration of Circulating Tumor Cells (CTCs) are key indicators of epithelial cancers, which often release tumor cells into the bloodstream. Current methods include density-based separation via centrifugation and physical filtration using commercial filters. However, these techniques have notable limitations: long processing times, stringent sample preparation to prevent contamination, low CTC recovery, and the need for expensive equipment. Microfluidics offers a promising alternative with simpler devices, faster results, and improved separation. Our design uses the reverse wavy channels from the study published by Zhou et. al [2] and by constraining the entire channel in a circular channel, thus incorporating more turns in the design in a relatively small space, thus potentially reducing costs in manufacturing, smaller overall footprint of the device and reduced pressure losses compared to longer channels. In this study the separation characteristics of CTCs from Blood Cells are analyzed at different Re and at different Aspect Ratios, thus determining the optimum parameters for operation and separation, which show maximum separation occurring at a Reynold’s Number of 40 and an Aspect Ratio of 0.32. Furthermore, significant separation is seen to be achieved after 4 reverse wavy channel patterns indicating the number of channel patterns could also be reduced for even smaller footprint of the device. The addition of dielectrophoresis to the existing system could potentially improve the separation and have better sample purity.