Fast determination of mitochondria electrophoretic mobility using micro free-flow electrophoresis

Fast, continuous separation of mitochondria from rat myoblasts using micro free-flow electrophoresis ([micro]FFE) with online laser-induced fluorescence detection (LIF) is reported. Mitochondrial electrophoretic profiles were acquired in less than 30 s. In comparison to macroscale FFE instruments, [micro]FFE devices consumed approximately l00-fold less sample, used l0-fold less buffer, and required a 15-fold lower electric field. Mitochondrial electrophoretic mobility distributions measured using [micro]FFE were compared to those measured with a capillary electrophoresis instrument with laser-induced fluorescence detection (CE-LIF). There was high similarity between the two distributions with CE-LIF distribution being offset by 1.8 x [10.sup.-4] [cm.sup.2] [V.sup.-1] [s.sup.-1] with respect to the [micro]FFE distribution. We hypothesize that this offset results from the differences in electric field strength used in the techniques. In comparison to CE-LIF, analysis of mitochondria using [micro]FFE greatly decreased separation time and required less separation voltage, while maintaining low sample (125 nL) and buffer (250 [micro]L) volumes. These features together with the potential for collecting separated organelle fractions for further characterization make [micro]FFE a very attractive tool for the high-throughput analysis of organelle subpopulations as well as investigating the fundamentals of the electrophoretic mobility of biological particles. 10.1021/ac901508x