Abstract 3477: Continuous isolation, labeling and collection of viable CTCs using an integrated microfluidic device
Authors: Rhonda M. Jack, Meggie MG Grafton, Robert A. Cieslak, Denise C. Jue, Cathy Griffith, Danika Rodrigues, Sunitha Nagrath, Diane Simeone
Journal: Cancer Research (2014)

Abstract The concept of studying tumor-derived circulating tumor cells (CTCs) from a simple blood-draw of a patient, has acquired significant attention in recent years. This relatively non-invasive approach opens many avenues in understanding and monitoring quite a number of cancers where correlations have since been made with CTCs and patient survival as well as patient response to therapeutics. Additionally, studies geared towards identifying genetic markers as well as gene profiling of CTCs are ongoing in efforts to develop early screening markers as well as gain a more holistic understanding of the various forms of the disease. Moreover, the concept of personalized medicine in treating several types of cancer is deemed indispensable due to the highly heterogeneous nature of the disease. Extensive studies involving genetic material of CTCs are expected to considerably develop effective therapeutics that are tailored to meet each patient's need. However, several challenges need to be overcome in order to harness the wealth of information that can be gained from CTC studies, such as the rarity of such cells among other blood cells, where CTCs occur as rarely as 1 to 1 million among other mononuclear blood cells. In this vein we discuss the development of an integrated, continuous microfluidic device designed to isolate and label CTCs disseminated from cancer tumors. The 3-part device initially exploits the size disparity of the majority of CTCs with other blood cells and couples this with the use of size-based inertial forces to presort CTCs from whole blood at 1.2mL/min. The CTC-rich fluid stream is then mixed passively, on-chip, with EpCAM coated micro-beads which allows the cells and beads to mix at the micron length scale. This is followed by a brief period of incubation which allows cells to be sufficiently labeled, where the majority of cells have experienced at least two-thirds magnetic bead coverage using this mixing-incubation approach. Thereafter on-chip magnetic sorting of CTCs from any remaining blood cells is achieved by application of an external magnet along the magnetic sorter of the integrated device. Cells with as little as one-third bead coverage experience magnetic deflection to the CTC collection stream. To identify CTCs, cells were stained positively for DAPI and CK-19, and CD45 was used to distinguish leukocytes. We demonstrate that the isolated CTCs are not only viable but that the range of WBC decontamination is the lowest yet reported in literature. Based on PANC-1 cell-line experiments with the device, an 80% recovery rate of cancer cells from other blood cells was consistently achieved. Testing of metastatic patient samples with the device has yielded high counts of CTCs, coupled with high purity rates. We believe that the use of this system in characterizing CTCs and studying cancer will contribute to understanding this aggressive disease in a non-invasive, efficient manner. Citation Format: Rhonda M. Jack, Meggie MG Grafton, Robert A. Cieslak, Denise C. Jue, Cathy Griffith, Danika Rodrigues, Sunitha Nagrath, Diane Simeone. Continuous isolation, labeling and collection of viable CTCs using an integrated microfluidic device. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3477. doi:10.1158/1538-7445.AM2014-3477