Diffusion of macromolecules in agarose gels: Comparison of linear and globular configurations

Alain Pluen, Paolo A. Netti, Rakesh K. Jain, David A. Berk

    Research output: Contribution to journalArticlepeer-review


    The diffusion coefficients (D) of different types of macromolecules (proteins, dextrans, polymer beads, and DNA) were measured by fluorescence recovery after photobleaching (FRAP) both in solution and in 2% agarose gels to compare transport properties of these macromolecules. Diffusion measurements were conducted with concentrations low enough to avoid macromolecular interactions. For gel measurements, diffusion data were fitted according to different theories: polymer chains and spherical macromolecules were analyzed separately. As chain length increases, diffusion coefficients of DNA show a clear shift from a Rouse-like behavior (D(G) ≃ N0/-0.5) to a reptational behavior (D(G) ≃ N0/-2.0). The pore size, a, of a 2% agarose gel cast in a 0.1 M PBS solution was estimated. Diffusion coefficients of the proteins and the polymer beads were analyzed with the Ogston model and the effective medium model permitting the estimation of an agarose gel fiber radius and hydraulic permeability of the gels. Not only did flexible macromolecules exhibit greater mobility in the gel than did comparable-size rigid spherical particles, they also proved to be a more useful probe of available space between fibers.
    Original languageEnglish
    Pages (from-to)542-552
    Number of pages10
    Issue number1
    Publication statusPublished - Jul 1999


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