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Electrophoretic ratcheting of spherical particles in well/channel microfluidic devices: Making particles move against the net field
Author(s) -
Wang Hanyang,
de Haan Hendrick W.,
Slater Gary W.
Publication year - 2020
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201900299
Subject(s) - electrophoresis , electric field , microfluidics , materials science , nonlinear system , field (mathematics) , inversion (geology) , chemical physics , molecular physics , nanotechnology , physics , chemistry , chromatography , paleontology , quantum mechanics , structural basin , biology , mathematics , pure mathematics
We examine the electrophoresis of spherical particles in microfluidic devices made of alternating wells and narrow channels, including a system previously used to separate DNA molecules. Our computer simulations predict that such systems can be used to separate spherical particles of different sizes that share the same free‐solution mobility. Interestingly, the electrophoretic velocity shows an inversion as the field intensity is increased: while small particles have higher velocities at low field, the situation is reversed at high fields with the larger particles then moving faster. The resulting nonlinearity suggests that asymmetric pulsed electric fields could be used to build separation ratchets: particles then have a net size‐dependent velocity in the presence of a zero‐mean external field. Exploiting the inversion mentioned above, we show how to design pulsed field sequences that make particles move against the mean field (an example of negative mobility). Finally, we demonstrate that it is possible to use pulsed fields to make particles of different sizes move in opposite directions, even though their charge have the same sign.