Synthesis and characterization of a hydrogel with controllable electroosmosis: A potential brain tissue surrogate for electrokinetic transport

Amir H. Faraji, Jonathan J. Cui, Yifat Guy, Ling Li, Colleen A. Gavigan, Timothy G. Strein, Stephen G. Weber

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Electroosmosis is the bulk fluid flow initiated by application of an electric field to an electrolyte solution in contact with immobile objects with a nonzero λ-potential such as the surface of a porous medium. Electroosmosis may be used to assist analytical separations. Several gel-based systems with varying electroosmotic mobilities have been made in this context. A method was recently developed to determine the λ-potential of organotypic hippocampal slice cultures (OHSC) as a representative model for normal brain tissue. The λ-potential of the tissue is significant. However, determining the role of the λ-potential in solute transport in tissue in an electric field is difficult because the tissue's λ-potential cannot be altered. We hypothesized that mass transport properties, namely the λ-potential and tortuosity, could be modulated by controlling the composition of a set of hydrogels. Thus, poly(acrylamide-co-acrylic acid) gels were prepared with three compositions (by monomer weight percent): acrylamide/acrylic acid 100/0, 90/10, and 75/25. The λ-potentials of these gels at pH 7.4 are distinctly different, and in fact vary approximately linearly with the weight percent of acrylic acid. We discovered that the 25% acrylic acid gel is a respectable model for brain tissue, as its λ-potential is comparable to the OHSC. This series of gels permits the experimental determination of the importance of electrokinetic properties in a particular experiment or protocol. Additionally, tortuosities were measured electrokinetically and by evaluating diffusion coefficients. Hydrogels with well-defined λ-potential and tortuosity may find utility in biomaterials and analytical separations, and as a surrogate model for OHSC and living biological tissues.

Original languageEnglish (US)
Pages (from-to)13635-13642
Number of pages8
JournalLangmuir
Volume27
Issue number22
DOIs
StatePublished - Nov 15 2011

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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