On passing a non-Newtonian circulating tumor cell (CTC) through a deformation-based microfluidic chip

Abstract

Circulating tumor cells (CTCs) are potential indicators of cancer. Detection of CTCs is important for diagnosing cancer at an early stage and predicting the effectiveness of cancer treatment. Among various devices, deformation-based CTC microchips have shown a strong promise for CTC detection. This type of devices involves a process where CTCs are trapped while allowing more deformable blood cells to squeeze through the filtration geometry at the specified operating pressure. For designing a reliable CTC microchip, in-depth understanding of the cell passing process through the deformation-based microfluidic device is of high value to the device performance enhancement. In this paper, the CTC squeezing process through a microfluidic filtering channel is studied with a non-Newtonian CTC model employed to account for shear-thinning properties of the cell. Detailed microscopic multiphase flow characteristics regarding the filtering process are discussed including the pressure signatures, flow details, cell deformation, and viscosity variation. Critical pressure for the non-Newtonian CTC at different flow rates is analyzed as it plays a crucial role in the device operation in ensuring a successful passing event. Our study provides insights into the non-Newtonian cell squeezing process, which can guide in the design and optimization of next-generation deformation-based CTC microfilters.