A novel ultra‐low conductivity electromanipulation buffer improves cell viability and enhances dielectrophoretic consistency

Authors: Hyler AR, Hong D, Davalos RV, Swami NS, Schmelz EM.

Electrophoresis, Volume 42, Issue 12-13, 2021

 

Cell separation has become a critical diagnostic, research, and treatment tool for personalized medicine. Despite significant advances in cell separation, most widely used applications require the use of mulitple, expensive antibodies to known markers in order to identify subpopulations of cells for separation. Diaelectrophoresis (DEP) provides a biophysical separation technique that can target cell subpopulations based on phenotype without labels and return native cells for downstream analysis. One challenge in employing any DEP device is the sample being separated must be transferred into an ultra-low conductivity medium, which can be detrimental in retaining cells' native phenotypes for separation. Here, we measured properties of traditional DEP reagents and determined that after just 1-2 hours of exposure and subsequent culture, cell's viaiblity was significantly reduced below 50%. We developed and tested a novel buffer (CytoBuffer) that achieved 6 weeks of stable shelf life and demonstrated significantly imporved viability and physiologicla properties. We then dtermined the impmact of CytoBuffer on cell's dielectric properties and morphology and found that cells retained properties more similar to that of their native media. Finally, we vetted CytoBuffer's usability on a cell separation platform (Cyto R1) to determine combined efficacy for cell seperations. Here, more than 80% of cells from different cell lines were recovered and were dtermined to be >70% viable following exposure to CytoBuffer, flow stimulation, electromanipulation, and downstream collection and growth. The developed buffer demonstrated opportunities for electrical manipulation, enrichment, and recovery for next generation cell separations.