Interactions Between Circulating Tumor Cells and Aptamer-Functionalized Microposts in a Flow

Abstract

Circulating Tumor Cells (CTCs) have been considered as important biomarkers for cancer prognosis and treatment. However, there are only tens of CTCs in one billion of healthy blood cells. This CTC rarity challenge has been addressed by microfluidics technology that sheds light on efficient CTC detection and isolation. Using antibodies or aptamers to capture CTCs is one of the strategies for CTC isolation. A lot of work has been carried out to improve CTC capture efficiency and purity (i.e., specificity). The main consideration to optimize microfluidic device performance includes increasing surface-area-to-volume ratio and reducing shear stress, both of which are closely related to the interaction between CTCs and the microfluidic device. Here we report a detailed study on the interactions between CTCs and aptamer-functionalized microposts in a microfluidic device. We have evaluated the distribution of captured CTCs around a micropost. In addition, simulation was conducted to model CTC capture patterns around microposts. We found the simulated CTC capture pattern largely agree with the experimental results. The simulation methodology could be applicable for other affinity-based CTC isolation devices and approaches. The goal of the study is to improve the microfluidic device performance and provide a rapid and economical way to optimize the geometry design of the microfluidic devices for CTC isolation.