Article
Concentration-polarization electroosmosis near insulating constrictions within microfluidic channels
Author/s | Fernández Mateo, Raúl
Calero Martín, Víctor Morgan, Hywel Ramos Reyes, Antonio García Sánchez, Pablo |
Department | Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo |
Publication Date | 2021 |
Deposit Date | 2021-11-29 |
Published in |
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Abstract | Electric fields are commonly used to trap and separate micro- and nanoparticles near channel constrictions in microfluidic devices. The trapping mechanism is attributed to the electrical forces arising from the nonhomogeneous ... Electric fields are commonly used to trap and separate micro- and nanoparticles near channel constrictions in microfluidic devices. The trapping mechanism is attributed to the electrical forces arising from the nonhomogeneous electric field caused by the constrictions, and the phenomenon is known as insulator-based-dielectrophoresis (iDEP). In this paper, we describe stationary electroosmotic flows of electrolytes around insulating constrictions induced by low frequency AC electric fields (below 10 kHz). Experimental characterization of the flows is described for two different channel heights (50 and 10 μm), together with numerical simulations based on an electrokinetic model that considers the modification of the local ionic concentration due to surface conductance on charged insulating walls. We term this phenomenon concentration-polarization electroosmosis (CPEO). The observed flow characteristics are in qualitative agreement with the predictions of this model. However, for shallow channels (10 μm), trapping of the particles on both sides of the constrictions is also observed. This particle and fluid behavior could play a major role in iDEP and could be easily misinterpreted as a dielectrophoretic force. |
Funding agencies | Agencia Estatal de Investigación. España PGC2018- 099217-B-I00 |
Project ID. | PGC2018- 099217-B-I00 |
Citation | Fernández Mateo, R., Calero Martín, V., Morgan, H., Ramos Reyes, A. y García Sánchez, P. (2021). Concentration-polarization electroosmosis near insulating constrictions within microfluidic channels. Analytical Chemistry, 93 (44), 14667-14674. |
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