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Driven Bead Rheology of Mucus

Comparison of bead rheology and cone and plate (cap) rheology for concentrated λ-dna solution (1.4 mg/ml) as a function of shear rate. Diffusive bead rheology (diff-br) is a low shear rate measurement and plot-ted as a horizontal line. Driven magnetic bead rheology (DMBR) shows shear thinning consistent with cap, inset is DMBR creep relaxation curves for three different applied forces. Right is plot of sputum heterogeneity measured in a single COPD patient specimen.
Comparison of bead rheology and cone and plate (cap) rheology for concentrated λ-dna solution (1.4 mg/ml) as a function of shear rate. Diffusive bead rheology (diff-br) is a low shear rate measurement and plot-ted as a horizontal line. Driven magnetic bead rheology (DMBR) shows shear thinning consistent with cap, inset is DMBR creep relaxation curves for three different applied forces. Right is plot of sputum heterogeneity measured in a single COPD patient specimen.

We have used our 3DFM and magnetic high throughput technology to successfully measure the viscoelastic properties of mucus and have used concentrated DNA solutions as a viscoelastic standard to compare with funda-mental polymer physics models. We have demonstrated that our driven magnetic bead rheology (DMBR) methodology can measure the viscoelastic properties of fluids, including shear thinning, and in the limit where the probe size is larger than the characteristic size of the medium, replicate the properties measured by tradi-tional cone and plate rheometry (CAP). Most important is to appreciate the heterogeneity of these specimens. This can be quantified by observing the spread in driven bead values.

Spero, R.C., L. Vicci, J. Cribb, D. Bober, V. Swaminathan, E.T. O’Brien, S.L. Rogers, and R. Superfine, High throughput system for magnetic manipulation of cells, polymers, and biomaterials. Review of Scientific Instruments, 2008. 79(8): p. 083707.

Fisher, J.K., L. Vicci, K. Bloom, E.T. O’Brien, C.W. Davis, R.M. Taylor II, and R. Superfine, Magnetic Manipulation for the Biomedical Sciences, in Handbook of Nanosciences, Engineering, and Technology, Second Edition. 2007, CRC Press LLC: Boca Raton.