Self-consistent field theory investigation of the behavior of hyaluronic acid chains in aqueous salt solutions

In this work we continue to develop a field-theoretic methodology, which combines the technique of Gaussian equivalent representation for the calculation of functional integrals with the continuous Gaussian thread model of flexible polymers for solving statistical–mechanical problems of polyelectrolyte solutions. We present new analytic expressions for the osmotic pressure, the potential of mean force, and the monomer–monomer pair distribution function, and employ them to investigate the structural and thermodynamic quantities of the polyelectrolyte system. We demonstrate the applicability of the method for systems of polyelectrolyte chains in which the monomers interact via a Yukawa-type pair potential. As a specific example, the present work focuses on aqueous solutions of hyaluronic acid with added salts NaCl and CaCl₂. Hyaluronic acid is a high molecular weight linear polysaccharide, which has a multitude of roles in biological tissues. We conclude that the effect of sodium chloride and calcium chloride on the osmotic properties of hyaluronic acid solutions can be accounted for by their contributions to the ionic strength. Nevertheless, the effects of coiling and self-association can be stimulated in solution by added salt.