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Dynamics and Structure of Biopolyelectrolytes Characterized by Dielectric Spectroscopy |
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| Authors: | Silvia Tomić Danijel Grgičin Tomislav Ivek Sanja Dolanski Babić Tomislav Vuletić Georg Pabst Rudi Podgornik |
| Institution: | 1. Institut za fiziku, Bijenička cesta 46, 10000 Zagreb, Croatia;2. Institut za fiziku, Bijenička cesta 46, 10000 Zagreb, Croatia
Department of Physics and Biophysics, Medical School, University of Zagreb, Šalata 3, 10000 Zagreb, Croatia;3. Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz, Austria;4. Department of Physics, Faculty of mathematics and physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia and J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia |
| Abstract: | Structural properties of Na-DNA and Na-HA aqueous solutions can be quantified using dielectric spectroscopy in the frequency range 100 Hz–100 MHz. Two relaxation modes are typically detected that can be attributed to diffusive motion of polyion counterions. The overall study as a function of polyion length, concentration and added salt concentration demonstrates that the motion of polyion counterions detected at MHz frequencies probes collective properties, whereas the motion at kHz range probes single-chain properties of polyelectrolytes. Fundamental length scales found to characterize the polyelectrolyte structure differ for the dilute and semidilute regime and also depend on the strength of electrostatic interactions and the flexibility. Characteristic length scales detected in the dielectric spectroscopy measurements compare well with the fundamental length scales predicted by theory and comply with those extracted from small-angle X-ray scattering. |
| Keywords: | biomaterials dielectric properties dynamics and conformational changes polyelectrolytes small-angle X-ray scattering (SAXS) |