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Comprehensive model of electromigrative transport in microfluidic paper based analytical devices
Author(s) -
Schaumburg Federico,
Kler Pablo A.,
Berli Claudio L. A.
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.201900353
Subject(s) - electromigration , porous medium , diffusion , mechanics , microfluidics , flow (mathematics) , capillary action , electrophoresis , transport phenomena , channel (broadcasting) , biological system , computer science , materials science , statistical physics , porosity , chemistry , physics , nanotechnology , thermodynamics , chromatography , computer network , biology , composite material
A complete mathematical model for electromigration in paper‐based analytical devices is derived, based on differential equations describing the motion of fluids by pressure sources and EOF, the transport of charged chemical species, and the electric potential distribution. The porous medium created by the cellulose fibers is considered like a network of tortuous capillaries and represented by macroscopic parameters following an effective medium approach. The equations are obtained starting from their open‐channel counterparts, applying scaling laws and, where necessary, including additional terms. With this approach, effective parameters are derived, describing diffusion, mobility, and conductivity for porous media. While the foundations of these phenomena can be found in previous reports, here, all the contributions are analyzed systematically and provided in a comprehensive way. Moreover, a novel electrophoretically driven dispersive transport mechanism in porous materials is proposed. Results of the numerical implementation of the mathematical model are compared with experimental data, showing good agreement and supporting the validity of the proposed model. Finally, the model succeeds in simulating a challenging case of free‐flow electrophoresis in paper, involving capillary flow and electrophoretic transport developed in a 2D geometry.