Abstract
We describe a new, high-resolution technique for determining the local viscoelastic response of polymer gels on a micrometer scale. This is done by monitoring thermal fluctuations of embedded probe particles. We derive the relationship between the amplitude of fluctuations and the low-frequency storage modulus G′, as well as the relationship between the fluctuation power spectrum, measured between 0.1 Hz and 25kHz, and the complex shear modulus G(ω). For both, semiflexible F-actin solutions and flexible polyacrylamide (PAAm) gels we observe high-frequency power-law dependence in the spectra, which reflects the behavior of the shear modulus. However, we observe distinctly different scaling exponents for G(ω) in F-actin and PAAm gels — presumably due to the semiflexible nature of the actin filaments.
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Schnurr, B., Gittes, F., Olmsted, P.D. et al. Local Viscoelasticity of Biopolymer Solutions. MRS Online Proceedings Library 463, 15–20 (1996). https://doi.org/10.1557/PROC-463-15
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DOI: https://doi.org/10.1557/PROC-463-15