Capillary sodium dodecyl sulfate-DALT electrophoresis of proteins in a single human cancer cell

Capillary Sodium dodlecyl sulfate (SDS)-DALT an (abbreviation for Dalton) e lectrophoresis was applied to analysis of proteins in single HT29 human col on adenocarcinoma cells. A vacuum pulse was employed to introduce a single cell into the coated capillary. Once the cell was lysed, proteins were dena tured with SIDS, fluorescantly labeled with 3-(2-furoyl)-quinoline-2-carbox aldehyde (FQ), and then separated by using 8% pullulan as the sieving matri x. This method offers a few advantages for single-cell protein analysis. Fi rst, it provides reproducible separation of single-cell proteins according to their size. Based on comparison with the migration time of standard prot eins, most components from a single HT29 cancer cell have molecular masses within the range of 10-100 kDa. Second, as a one-dimensional separation met hod, it gives fairly good resolution for proteins. Typically, around 30 pro tein components of a single HT29 cell were resolved, indicating that this m ethod has similar peak capacity to SDS-polyacrylamide gel electrophoresis ( PAGE). Third, this method shows high detection sensitivity and wide dynamic range, which is important because of the wide range of protein expression in living systems. Detection limits for standard proteins ranged from 10(-1 0) to 10(-11) m. Finally, this method provides much higher speed than class ical gel electrophoresis methods, and it provides automated anlysis of cell ular proteins at the sing le-cell level; the separation is complete in 30 m in and the entire analysis takes similar to 45 min.