The CytoR1TM: A Standardized Dielectrophoretic Platform for Label-Free Sorting

DE Thomas, KE Degen, R Barua, A Bertke, EA Henslee, AR Hyler. The CytoR1: a standardized dielectrophoretic platform for label-free sorting. American Association for Cancer Research Annual Meeting, Orlando, FL. April 2023.

Dielectrophoresis (DEP), a label-free electrokinetic technique, has a long history of being used to characterize and separate target subpopulations from mixed samples. A large body of literature has investigated these parameters with unique setups and limited cell varieties. The technical challenge of the technique coupled with the uncertainty in the breadth of data has limited the commercialization and widespread adoption of DEP for biological applications. The work presented here aims to evaluate a range of prior applications of DEP on a standardized platform. A variety of cell types were characterized and compared to literature values considering variables such as frequency, voltage, and flow rate. Once a cell type's frequency response curve is generated, it is possible to design workflows to enrich that cell type from a bulk mixture, without antibody labeling. Here, we test various cell types and characteristics on a microfluidics-based, benchtop cell sorting technology, the CytoR1. First, the CytoR1 successfully facilitated the separation of ovarian cancer stem cells (CSCs) from peripheral blood mononuclear cells (PBMCs), both from mice. From a 56.2% CSCs and 43.8% PMBCs co-culture, we were able to deplete 50% of the PMBCs while retaining the original CSC population. Further work investigated the ability to sort neuron subpopulations. Live neurons can be isolated from a bulk preparation and further enriched by size and phenotype with varying voltage and frequency settings. By modulating voltage and flow rate in addition to frequency, a distinct population of small neurons can be isolated for further study. Finally, cell state can be investigated. Red blood cells were characterized in both their native and oxidatively stressed states. Curves show a distinct shift towards higher frequencies with increasing oxidative stress suggesting the ability to separate these populations from each other. Together these data suggest the versatility of a robust, DEP-based sorting platform, the CytoR1, for label-free cell sorting.

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