Suppression of aggregation in natural-semiflexible/flexible polyanion mixtures, and direct check of the OSF model using SANS

Abstract

Aggregation and other interactions are suppressed for a biological semiflexible polyelectrolyte, hyaluronan (HA), when it is embedded in a mixture with another negatively charged and flexible polyelectrolyte chain, sodium polystyrene sulfonate. We see directly HA only in the mixture using Small-Angle Neutron Scattering, isotopic labelling and contrast matching. At low ionic strength, for which aggregation is usually seen for pure HA solutions, an unambiguous set of experimental results shows that we neither observe HA aggregation nor a polyelectrolyte peak (observed for solutions of single species); instead we observe a wormlike chain behaviour characteristic of single chain with a variation of the persistence length with the square of the Debye screening length, L e~ -2 , as formerly predicted by Odijkand not yet observed on a polymer chain.

Structure and dynamics of hyaluronic acid semidilute solutions: A dielectric spectroscopy study

“…3 in Ref. [39] reveals that the apparent OSF behavior of data critically depends on the 0.1 M (0.2 M) single data point which is not obtained from experiment, but is rather calculated from the OSF formula. This result apparently contradicts our results obtained by dielectric spectroscopy measurements, but only for added salt concentrations smaller than 1 mM.…”

Role of the ratio of biopolyelectrolyte persistence length to nanoparticle size in the structural tuning of electrostatic complexes

“…In the first place, the NPs are still silica NPs but another surface modification was used to bring positive charges onto their surface. The chosen partner is hyaluronan, a polyelectrolyte polysaccharide displaying a semi-flexible backbone with an intrinsic persistence length L p ~5 nm [33][34][35] (iv) Finally, the influence of electrostatic interactions was also considered by varying the ionic strength, I. In the absence of external salt, the electrostatic contribution to the persistence length L e depends only on the concentration of the counterions of the two species, allowing a wide variation of L T /R, which is controlled by both the screening and the nature of the PEL.…”

“…In the first place, the NPs are still silica NPs but another surface modification was used to bring positive charges onto their surface. The chosen partner is hyaluronan, a polyelectrolyte polysaccharide displaying a semi-flexible backbone with an intrinsic persistence length L p~5 nm [33][34][35] In what follows, we compare original data from the three systems. The phase behavior in the PEL-NP-L T /R diagram as well as the structure of the complexes in all characteristic phase domains has been determined using small-angle neutron scattering (SANS) experiments in the presence and absence of external salt.…”

Rodlike Complexes of a Polyelectrolyte (Hyaluronan) and a Protein (Lysozyme) Observed by SANS

“…This is well documented since HA has been studied as single specie in aqueous solution for some time 41 . We took particular advantage of direct studies of conformation using also neutron (combined with light) scattering, in pure solution 42 as well as in a mixture with another polyion, sodium polystyrene sulfonate (PSSNa) 43 . The choice of the lysozyme as protein is twofold as well:…”