Divergent flow isoelectric focusing.
Continuous-flow isoelectric focusing (IEF) has the potential to be an important method in proteome analysis. The current devices do not fully use the advantages of IEF, because they do not utilize all its important features including changes in background conductivity during the focusing. A novel continuous-flow IEF method has been developed based on planar divergent flow and control of local electric field by conductivity of electrode electrolytes. A hydrophilized polypropylene nonwoven fabric was used for creation of flow and electric manifold, making the assembled device cheap, flexible and easy to set up and operate. By using the colored low-molecular-weight pI markers we demonstrated much higher speed of focusing in the new designed channel in comparison with a channel based on currently used rectangular geometry. The developed divergent-flow IEF combines the speed of micro flow channels with the separation efficiency and sample load capacity of preparative devices.