Circulomics has published a new technology for electrode free concentration of DNA called molecular rheotaxis. This work, entitled "Molecular Rheotaxis Directs DNA Migration and Concentration Against a Pressure-Driven Flow," will be published in Nature Communications and was performed in conjunction with Dr. Tza-Huei Wang of Johns Hopkins University and Dr. Neil Ivory of Washington State University.
Molecular rheotaxis can be used to concentrate DNA into a small bolus at a capillary inlet without electrodes or applied electric fields. As buffer is pumped out of a capillary into a sample well, DNA migrates against the flow and gathers into a highly concentrated at the capillary inlet. Concentration factors surpassing 10,000-fold were achieved using simple buffer systems. This method was combined with single molecule free solution hydrodynamic separation to perform DNA sizing using samples with concentrations as low as 150 aM.
As no electrodes are required and the buffer requirements are very simple, this method can be combined with any number of chromatographic or electrophoretic separation methods to significantly improve detection sensitivity.