Electrokinetic Trapping and Concentration Enrichment of DNA in a Microfluidic Channel Jinhua Dai Takashi Ito Li Sun Richard M. Crooks 10.1021/ja0374776.s001 https://acs.figshare.com/articles/media/Electrokinetic_Trapping_and_Concentration_Enrichment_of_DNA_in_a_Microfluidic_Channel/3361015 We report a simple and efficient method for enriching the concentration of charged analytes within microfluidic channels. The method relies on exerting spatial control over the electrokinetic velocity of an analyte. Specifically, the electroosmotic (eo) velocity of the buffer solution in one region of the microfluidic system opposes the electrophoretic (ep) velocity of the analyte in the other region. This results in ep transport of DNA to the location where the ep and eo velocities are equal and opposite. Accumulation of the analyte occurs at this location. This enrichment method is conceptually distinct from field-amplification stacking, isotachophoresis, micelle sweeping, size exclusion, and other methods that have been previously reported. The method requires no complex microfabricated structures, no special manipulation of the solvent, and the enriched analyte remains in solution rather than being captured on a solid support. A concentration enrichment factor of 800 can be achieved for 20mer DNA in a fluidic channel having dimensions of 100 μm × 25 μm × 5 mm. The time required to achieve this level of enrichment is 300 s, and the enriched zone has a minimum width of 100 μm. 2003-10-29 00:00:00 Microfluidic Channel fluidic channel eo velocities concentration enrichment factor analyte enrichment method size exclusion location Electrokinetic Trapping 100 μ m microfluidic system electrokinetic velocity microfluidic channels 20 mer DNA microfabricated structures buffer solution Concentration Enrichment ep transport region