Static and dynamic behavior of aggrecan solutions
- PDF / 970,024 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 52 Downloads / 253 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.480
Static and dynamic behavior of aggrecan solutions Ferenc Horkay1*, Peter J. Basser1, Erik Geissler2 1
Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 49 Convent Drive, Bethesda, MD 20892-5772, USA 2
Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, and CNRS, LIPhy, F-38402 St Martin d'Hères cedex, France
ABSTRACT Small angle neutron scattering (SANS) and dynamic light scattering (DLS) measurements were made on near physiological solutions of a bottlebrush shape polyelectrolyte, aggrecan. Aggrecan is a biologically important molecule whose complexes with hyaluronic acid (HA) provide the osmotic resistance of cartilage. We have investigated the effect of complexation of aggrecan with HA on the structure and dynamic properties of aggrecan solutions. SANS reveals that the supramolecular structure of aggrecan assemblies is only marginally affected by the HA. DLS indicates that the dynamic response of the aggrecan-HA complex is slower than that of the corresponding aggrecan solution. However, addition of calcium ions slightly increases the relaxation rate of the autocorrelation function of the aggrecan solution.
INTRODUCTION Aggrecan is a bottlebrush shaped high molecular weight proteoglycan. It consists of an extended protein core to which many chondroitin sulfate and keratan sulfate (linear sulfated polysaccharide) chains are attached [1-4]. Aggrecan’s primary biological role is to provide the osmotic properties for cartilage. In the presence of hyaluronic acid (HA) aggrecan molecules self-assemble into a supramolecular structure with as many as 100 macromonomers bound to a HA molecule. The aggrecan-HA complexes govern the load bearing properties of cartilage [5-7]. In complex biological molecules such as aggrecan and its assemblies many specific interactions are responsible for the hierarchical organization of the structural elements, e.g., ordering, hydrophobic interactions and hydration forces. The presence of competing influences and coexisting structures makes it difficult to apply established physical concepts to such systems. Most solution properties of charged polymer
Downloaded from https://www.cambridge.org/core. University of Texas Libraries, on 20 Jan 2020 at 11:12:53, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.480
molecules are governed by the distribution of small ions in the neighborhood of their macroion. In the case of strong coupling, counterions are assembled around the polyion. For locally rod-like polymers the distribution of monovalent counterions can be described by the Poisson-Boltzmann theory [8]. In spite of many previous investigations in polyelectrolyte systems, the understanding of multivalent cations remains empirical. The aim of this work is to obtain information on the effects of HA and ca
Data Loading...
