A Computational Study on Non-Uniform Cross-Sectional Deformability-Based CTC Separation Devices

Abstract

Cancer is one of the most dangerous diseases widespread around the world. Developing the most efficient cures for cancer strongly relies on a comprehensive understanding of cancer cells. Circulating Tumor Cells (CTCs) are cancer cells detached from the primary tumor site and released into the blood. CTCs are the main source of cancer metastasis. Devising devices to identify and separate these cells from the blood is of great importance since these cells represent cancer in many aspects. Because of the rarity of CTCs in the blood, designing efficient CTC separation devices has become a challenging issue. Among different CTC separation devices, deformability-based CTC separation devices have become very popular recently because of their simplicity and their relatively low cost. In this research, we investigate numerically the deformability-based CTC separation microfilters. Specifically, we study non-uniform cross-sectional microfilters because of their ability in unclogging. Different microfilter geometries are selected for this study including conical-shaped and rectangular cross-section microfilters with different channel profiles. In this study, we mainly focus on the effect of different design parameters on system performance criteria. The main performance criteria are: critical pressure of the system, system throughput and cell clogging in filtration. Critical pressure, which is defined as the maximum pressure for a cancer cell to squeeze through the microfilter, is an important design aspect. Applying a pressure lower than the critical pressure causes the cell to get stuck in the microfilter, while applying much higher pressure on the system may result in cellular damage which has negative effect on the viability of the cell for post processing. System throughput is also of great importance. A high-throughput CTC filtration system is always more desirable in clinic applications. System clogging, which decreases the CTC separation efficiency, is one of the challenging issues in these devices. In this research, we first simulate how a cell behaves in a passing event process through the microfilter. Specifically, we focus on how different cells squeeze through the microfilter. This gives us more insight through the separation process. Second, we investigate the effect of different microfilter geometries on the critical pressure required for separation of cancer cells. Third, the effect of applied inlet pressure on the system performance is studied. Our results indicate that the critical pressure varies significantly with microfilter geometry. Results also show that the device throughput is strongly related to the applied pressure. Moreover, the filtration simulation demonstrates that system clogging occurs if unsuitable pressure is applied on the system.