Conformational Changes and Aggregation of Alginic Acid as Determined By Fluorescence Correlation Spectroscopy

Article Article scientifique Article Conformational Changes and Aggregation of Alginic Acid as Determined By Fluorescence Correlation Spectroscopy eng 2007 author Avaltroni Fabrice François 502627 author Seijo Marianne 590889 author Ulrich Serge 502638 author Stoll Serge 0000-0003-3158-4208 29148 author Wilkinson Kevin 29725 106-112 10.1021/bm060655d 1525-7797 Insight into the conformations and aggregation of alginic acid was gained by measuring its diffusion coefficient at very dilute concentrations using fluorescence correlation spectroscopy. Both the pH and ionic strength (I) had an important influence on the diffusion coefficient of the polysaccharide. For pH, three effects were isolated: (i) below pH 4, the charge density decreased causing increased aggregation; (ii) between pH 4 and 8, a molecular expansion was observed with increasing pH, whereas (iii) above pH 8 some dissociation of the polymer was observed. Increasing I from 0.001 to 0.1 M resulted in a ca. 20% increase in the diffusion coefficient. By coupling these measurements to molar mass determinations obtained by size exclusion chromatography and monomer size estimations determined from ab initio calculations, it was possible to determine the radii of gyration via de Gennes renormalization theory. From diffusion coefficients and radii of gyration obtained as a function of ionic strength, persistence lengths (total, electrostatic, and intrinsic) were calculated from the Benoit−Doty relationship. Conformational Changes Aggregation Alginic Acid Fluorescence Correlation Spectroscopy Ionic Strength Dewey 550 Swiss National Science Foundation Microstructures and dynamic processes in aquatic systems CH Project funding Autre Engineering Research Council of Canada 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false 755 Environmental Physical Chemistry Biomacromolecules 8 1 90995d84-f715-49e4-9ae4-0eb755164ed2 Article (Published version) Restricted bm060655d.pdf 195583 application/pdf restrictedAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

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Conformational Changes and Aggregation of Alginic Acid as Determined By Fluorescence Correlation Spectroscopy	Biomacromolecules			2007	433	1

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Avaltroni, Fabrice François