Journal article

Concentration gradient focusing and separation in a silica nanofluidic channel with a non-uniform electroosmotic flow

Wei-Lun Hsu, Dalton JE Harvie, Malcolm R Davidson, Helen Jeong, Ewa M Goldys, David W Inglis

Lab On a Chip: Microfluidic and nanotechnologies for chemistry, biology, and bioengineering | ROYAL SOC CHEMISTRY | Published : 2014

Abstract

The simultaneous concentration gradient focusing and separation of proteins in a silica nanofluidic channel of various geometries is investigated experimentally and theoretically. Previous modelling of a similar device [Inglis et al., Angew. Chem. Int. Ed., 2011, 50, 7546] assumed a uniform velocity profile along the length of the nanochannel. Using detailed numerical analysis incorporating charge regulation and viscoelectric effects, we show that in reality the varying axial electric field and varying electric double layer thickness caused by the concentration gradient, induce a highly non-uniform velocity profile, fundamentally altering the protein trapping mechanism: the direction of the ..

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