Abstract
Cell separation is an important component of modern medicine, with both clinical and research applications. Clinically, it is often desirable to isolate cell subpopulations providing focused treatment; on the research side, cell isolation is necessary for studies underpinning many discoveries in cell biology, further enabling research in areas such as regenerative medicine and cancer therapy. Cell separation requirements include high throughput, purity and recovery. Three cell separators dominate: fluorescence and magnetic-activated cell sorting and density-gradient centrifugation. Despite gold-standard establishing performances, they can be improved in affordability, throughput, and label-free cell separation implementation. A technology with potential to offer the next rotation of gold-standard cell separators is Dielectrophoresis, DEP. Two DEP cell separators are presented. The first, the Syringe Separator (SS), uses 3D-electrodes on a low-cost, disposable chip and a DEP field perpendicular to fluid flow; one cell type is passed through whilst the other is retained and subsequently recovered. Two-pass protocols achieved a 96.4% recovery at over 200,000 cells/second with <7% loss. Additionally, a three-step protocol removed 99.1% of RBCs spiked with cancer cells (100:1). Other SS implementations include hitherto unachieved separation of high and low quality nanowires and T-cell isolation. The second employs a novel electrode geometry termed the Canyon. Using a novel electrode fabrication method (Plotter-Canyon printing), Canyons were built of alternating layers of metal and non-metal. Cellular solutions flow through the Canyon directed to one of two outlets, one for each of the negative or positive DEP cell subpopulations. The Canyon cell separator achieved an 84% recovery and 10% loss at ~2,000 cells/second. We have demonstrated that DEP cell separators can be built to perform cell separations with high purity, rivalling established separators, at significantly higher throughput and recovery. The SS and Canyons are cheap, easy-to-operate and offer a stepwise improvement in conventional cell separation capabilities.