Coherent Nonlinear Chromatography
Sandia National Laboratories, US
microfluidics, nanofluidics, separation, ultrafast, dielectrophoresis, electrokinesis, non-uniform, patterned flow
The concept, modeling, and experimental application of coherent nonlinear chromatography (CNC) are presented. CNC is a novel separation technique that sorts particles and molecules ultra-rapidly via field interactions in the bulk of the suspending fluid induced by micro- and nano-patterned surfaces. CNC avoids chromatography’s reliance on repeated diffusion of particles to and from surfaces and can theoretically separate protein-scale molecules >105X faster than conventional chromatography. CNC sorts via a competition between linear and nonlinear transport of particles in applied fields, e.g., electric or hydrodynamic fields. The nonlinear transport is a particle-specific secondary flow when particles interact with spatial non-uniformities in the applied fields. These spatial non-uniformities can be created by lithographic patterning of channel surfaces, e.g., etching obstacles in the channel or depositing charge-modifying films. The spatial arrangement of these patterned non-uniformities dictates the function of the CNC device, e.g., time-of-flight separation; continuous spectrometer-like separation; concentration; or hybrid manipulation. The term “coherent” in CNC refers to spatially coherent patterning that can rapidly drive and linearly “amplify” separations in contrast to the square-root length dependence of chromatographic resolving power. Specific examples of CNC devices based on dielectrophoresis, electrokinesis, and entropic effects are detailed.
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Nanotech 2005 Conference Program Abstract