RESEARCH PROFILE - Double duty: isodielectric technique simultaneously separates and characterizes particles

摘要

Researchers have recently shown that a technique called isodielectric separation (IDS) can simultaneously separate particles and determine their electrical properties. Joel Voldman and graduate student Michael Vahey of the Massachusetts Institute of Technology report their results in a new AC paper (DOI 10.1021/ac8019575). Originally, Voldman and Vahey wanted to combine dielectrophoresis with spatial conductivity gradients to sort particles and cells on the basis of their electrical properties. In their initial publication on IDS, the engineers demonstrated that their equilibrium separation method could separate polystyrene beads on the basis of differences in surface conductance and separate live from dead yeast cells (Anal. Chem. 2008, 80, 3135-3143). But the researchers realized that the end positions of the separated particles were somehow linked to the properties of the particles, so they began work to clarify the correlation. "The key thing here is that you have a device that can not only separate cells according to their electrical properties but can also make measurements on them," says Voldman. "So [IDS] can be used to separate cells to get populations away from each other or separate them in space just to see what their properties are."