{"id":3696,"date":"2011-07-11T15:36:22","date_gmt":"2011-07-11T15:36:22","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/?p=3696"},"modified":"2011-07-19T20:55:18","modified_gmt":"2011-07-19T20:55:18","slug":"iso-dielectric-separation-of-cells-and-particles-2","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/iso-dielectric-separation-of-cells-and-particles-2\/","title":{"rendered":"Iso-dielectric Separation of Cells and Particles"},"content":{"rendered":"

The development of new techniques to separate and characterize cells with high throughput has been essential to many of the advances in biology and biotechnology over the past few decades.\u00a0 Continuing or improving upon this trend \u2013 for example, by developing new avenues for performing genetic and phenotypic screens \u2013 requires continued advancements in cell sorting technologies.\u00a0 Towards this end, we are developing a novel method for the simultaneous separation and characterization of cells based upon their electrical properties.\u00a0 This method, iso-dielectric separation (IDS), uses dielectrophoresis (the force on a polarizable object [1<\/a>] <\/sup>) and a medium with spatially varying conductivity to sort electrically distinct cells while measuring their effective conductivity (Figure 1).\u00a0 It is similar to iso-electric focusing, except that it uses DEP instead of electrophoresis to concentrate cells and particles to the region in a conductivity gradient where their polarization charge vanishes [2<\/a>] <\/sup> [3<\/a>] <\/sup> [4<\/a>] <\/sup>.<\/p>\n

Previously, we have demonstrated the ability to perform continuous-flow, label-free, non-binary separations using IDS on a wide variety of cells and particles, while simultaneously extracting quantitative information from these samples as they are sorted [4<\/a>] <\/sup>. In order to make IDS discovery more unknown cell types, dynamically changing the conductivity gradient is crucial for increasing the efficiency of finding the optimal separation condition. Therefore, we are developing a tri-syringe pump system to dynamically control conductivity gradients. We have verified the stability of the tri-syringe pump system via quantitative fluorescence imaging.\u00a0 Combining this gradient control system with a computer-controlled function generator and automated microscope, we plan to fully automate IDS separation and electrical profile screening (Figure 2).<\/p>\n\n\t\t