Separation of circulating tumor cells from blood using dielectrophoretic DLD manipulation.

Circulating Tumor Cells (CTCs) play a prominent role in early cancer detection. Emerging label-free techniques can be promising to CTC detection due to advantages in preserving cell integrity and minimal sample consumption. Deterministic Lateral Displacement (DLD) is a size-based label-free technique employing laminar flow for continuous sorting of suspended cells. However, separation based solely on size is challenging as the size distributions of CTCs tend to overlap with blood cells. Moreover, the rarity of CTCs in blood requires high throughput processing of samples for clinical utility. In this work, a dielectrophoretic DLD technique is presented to segregate CTCs from blood. This technique utilizes the cell size and dielectric properties as well as particle movement caused by polarization effect to accomplish continuous separation at high flow rates. A numerical model is developed and validated to investigate the effects of various parameters related to the fluid flow, micro-post array, and electric field. It is demonstrated that the dielectrophoretic DLD with specific post arrangement can continuously separate A549 lung CTCs from WBCs by applying a field frequency close to the crossover frequency of CTCs. The analysis further indicates that such a device can perform well despite uncertainties of CTC crossover frequencies. Additionally, efficient separation with minimum clogging can be achieved by setting the electric field perpendicular to fluid flow. The presented platform offers distinct advantages and can be potentially combined with techniques such as antibody-based immune-binding methods for rapid detection of CTCs.