Simulation study of rare cell trajectories and capture rate in periodic obstacle arrays

Microfluidic devices that contain periodic obstacle arrays are frequently used for capture of rare cells such as circulating tumour cells (CTC). Detailed computational analysis can give valuable insights into understanding of fluidic processes inside such devices. Using our previously developed Object-in-fluid framework, we investigate characteristics of a single CTC in a suspension of red blood cells. In this work, we describe a new model for evaluation of cell capture probability that includes the surface area of the cell-obstacle contact. We analyze individual trajectories of CTCs and their distribution between the obstacles during the transport through the device. We vary two parameters- hematocrit and column radius of the cylindrical obstacles. While the hematocrit has a slight influence on the CTC trajectories and the cell capture rate computed by the newly developed model, the effect of column radius is much more pronounced. We observe that increase in column radius increases the capture rate quadratically. And secondly, with the exception of the very small column radius, increase in hematocrit slightly decreases the capture rate linearly. (C) 2016 Elsevier B.V. All rights reserved.