title: High-throughput cell and particle characterization using isodielectric separation.
abstract: Separations can be broadly categorized as preparative, where the objective is to extract purified quantities of a sample from a complex mixture, or analytic, where the goal is to determine and quantify the contents of the original mixture. Here we demonstrate the application of a new microfluidic separation method, isodielectric separation (IDS), to a range of analytic separations involving cells and particles spanning several orders of magnitude in volume and electrical conductivity. In IDS, cells are dielectrophoretically concentrated to the region along an electrical conductivity gradient where their polarizability vanishes; by measuring this position--the isodielectric point (IDP)--as operating conditions such as the frequency and voltage of the applied electric field are varied, we are able to sort cells or particles with distinct IDPs while simultaneously characterizing their electrical properties. We apply this technique to measure the electrical properties of polystyrene microspheres, viable and nonviable cells of the budding yeast Saccharomyces cerevisiae , and murine pro B cells, including how these electrical properties vary with the electrical conductivity of the surrounding solvent.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 36-824, Cambridge, Massachusetts 02139, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Vahey
authors.forename: J
authors.initials: J
authors.lastname: Voldman
mesh_terms: D000818:Animals; D002460:Cell Line; D002469:Cell Separation / Q000295:instrumentation* / Q000379:methods*; D002470:Cell Survival; D017097:Electric Impedance; D006358:Hot Temperature; D007962:Leukocytes / Q000166:cytology; D051379:Mice; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000166:cytology
chemical_list: D011137:Polystyrenes