ChemInform Abstract: Conformation and Solution Properties of Water-Soluble Polysaccharides: Case Study of Hyaluronic Acid

Abstract

Publisher Summary The global conformation and properties of a polyelectrolyte with intrinsically weak stiffness in solution are greatly influenced by electrostatic stiffening and excluded-volume effects. When the polyelectrolyte is modeled by the Kratky-Porod wormlike chain, a special case of Yamakawa's helical wormlike chain, the former effect is predicted to appear as an increase in the persistence length with lowering ionic strength, but its experimental estimation generally requires knowledge about the latter effect. Thus the electrostatic excluded-volume problem, which remains unsettled, is most basic to the characterization of charged polysaccharides in solution. This chapter discusses excluded-volume effects in aqueous sodium chloride solutions of hyaluronic acid (sodium salt) by summarizing the recent studies on the conformation and properties of the charged polysaccharide. The chapter also focuses on the applicability of the quasi-twoparameter (QTP) theory for volume effects in wormlike or helical wormlike chains to the mean-square radius of gyration and the intrinsic viscosity [η] in aqueous NaCl with different salt concentrations Cs at 25°C. According to recent experimental studies, this theoretical scheme allows an almost quantitative, consistent description of excluded-volume effects on and [η] of nonionic, linear polymers, both flexible and stiff, so that its applicability to ionic chains deserves to be investigated by experiment. Detailed analyses of these properties and the particle scattering function P(θ) based on the wormlike chain are studied in the chapter. The electrostatic contributions to the persistence length and the excluded-volume strength are also discussed in relation to theoretical predictions.