Abstract 3956: DLD microfluidic purification and characterization of intact and viable circulating tumor cells in peripheral blood

Abstract

We have developed a microfluidic chip-to-chip approach to purify circulating tumor cells (CTC’s). The first, a DLD (deterministic lateral displacement) microchip contains an array of microposts arranged in sub-arrays of different gap sizes. The “product” outlet of the DLD chip is connected with a second magnetic-separation chip. In the DLD chip, cells and particles are deflected or “bumped” based on their size, whereas the second chip is designed to remove any cell or component tagged with a magnetic particle (MNP). Air pressure is applied to maintain a constant flow of sample and buffer throughout the system in a vertical fashion. First, whole blood is mixed with biotinylated antibodies to CD45 and strepavidin-MNP's for 20min, diluted in buffer and passed through the DLD chip where the blood interacts with the posts and cells are bumped based on a deterministic lateral displacement principle, thus separating blood components. The “product” fraction from the DLD chip containing white blood cells and other larger cells is directed to the magnetic chip and the “waste” fraction containing red blood cells, platelets, debris and soluble blood components is discarded. The second chip has an array of magnets, capturing the sav-MNP/CD45+-tagged cells thereby allowing the gentle free flow of rare cells towards the final product fraction. With the chip-to-chip configuration we are able to process up to 8ml of blood, removing >99.8% of red blood cells and >98% of white blood cells, with the remaining purified cell populations suitable for further analysis and characterization. Validation of the chip-to-chip approach using tumor-derived cancer cells, including MDA-MB-231, PC-3 and SKBR-3 cells, confirms a linear recovery of >80% of the spiked-cells with a viability of ∼90%. The minimum cell size captured by our approach is approximately 6μm ensuring the isolation of small-sized CTC’s. Multi-color flow cytometry and imaging analysis of the chip-to-chip isolated cells from blood of breast cancer patients confirms the purification and identification of unique populations of HER2+/CD45-/EpCAM+ and CD146+/CD44+ cells characteristic of breast carcinomas-among other rare cell populations. Our chip-to-chip approach allows a gentle purification of intact and viable rare cells from cancer patients’ blood, suitable for functional analysis, drug sensitivity tests and genetic characterization. Thus, we have developed a hands-free liquid biopsy capable of isolating and purifying rare circulating tumor cells. Citation Format: Myra Koesdjojo, Zendra Lee, Christopher Dosier, Tanisha Saini, Khushroo Gandhi, Alison Skelley, Lee Aurich, Gregory Yang, Tony Ward, Roberto Campos-González. DLD microfluidic purification and characterization of intact and viable circulating tumor cells in peripheral blood. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3956.

Automated leukocyte processing by microfluidic deterministic lateral displacement

“…Because cell recovery is high, detection of extremely rare CTCs for “liquid tumor biopsies” is an attractive area for investigation. In our own ongoing research, addition of an immunomagnetic module downstream of the DLD‐based size separation enriched CTCs . Assessment of intracellular antigens is another attractive extension of DLD microchip‐based cell processing that we are investigating.…”

Deterministic Lateral Displacement: The Next-Generation CAR T-Cell Processing?

“…We previously investigated adding inhibitors at the point of collection to shut down platelet activation pathways, and we demonstrated successful processing of blood from endstage cancer patients on DLD; a future direction of our research is to investigate how inhibitors at the point of collection, resulting in even greater purity of cells collected from DLD, would affect the downstream proliferation and activation of T cells. 30 The results shown here not only demonstrate a net greater number of T central memory cells delivered at day 15 compared to via other methods, but also show a process that lends itself more easily to automation. The manual steps required for DLD are significantly fewer (loading microchip and sample), and the most critical part, the actual separation, is completely hands-free.…”

“…We previously investigated adding inhibitors at the point of collection to shut down platelet activation pathways, and we demonstrated successful processing of blood from end-stage cancer patients on DLD; a future direction of our research is to investigate how inhibitors at the point of collection, resulting in even greater purity of cells collected from DLD, would affect the downstream proliferation and activation of T cells. 30…”