title: Polyelectrolyte multilayer films built from poly(L-lysine) and a two-component anionic polysaccharide blend.
abstract: The buildup of polyelectrolyte multilayer films made from poly(L-lysine) (PLL) as a polycation and from a blend of two anionic polysaccharides, namely, beta-1,3 glycan sulfate (GlyS) and alginate (Alg), was investigated as a function of the mass fraction, x, of GlyS in the blend, at a constant total weight concentration in polyanions. We find that the film thickness, after the deposition of a given number of layer pairs, reaches a minimum for x values lower than 0.1 (the position of this minimum could not be more precisely localized) and that the film thickness at intermediate values of x is the same as that of films built at the same concentration of GlyS in the absence of Alg (pure GlyS solution). Infrared spectroscopy in the attenuated total reflection mode shows that the weight fraction of GlyS in the multilayer films is much higher than its weight fraction, x, in the blend used to build the film. This preferential incorporation of GlyS over Alg is related to preferential interactions of GlyS as compared to Alg with PLL in solution, as measured by means of isothermal titration calorimetry. We also demonstrate that GlyS is able to displace Alg almost quantitatively from (PLL/Alg)n films but that in contrast Alg is not able to exchange GlyS from (PLL/GlyS)n films. These results, which combine adsorption from blended polyanion solutions, exchange of one polyanion already present in the film by the other in solution, and thermodynamic measurements, suggest that sulfated polymers are able to interact with polycations preferentially over polymers carrying carboxylated charged groups. These results give a first structural basis to the mechanism of preferential incorporation of a given polyanion with respect to another.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 977, 11 rue Humann, 67085 Strasbourg Cedex, France. vincent.ball@medecine.u-strasbg.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Ball
authors.forename: Falk
authors.initials: F
authors.lastname: Bernsmann
authors.forename: Cosette
authors.initials: C
authors.lastname: Betscha
authors.forename: Clarisse
authors.initials: C
authors.lastname: Maechling
authors.forename: Serge
authors.initials: S
authors.lastname: Kauffmann
authors.forename: Bernard
authors.initials: B
authors.lastname: Senger
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Voegel
authors.forename: Pierre
authors.initials: P
authors.lastname: Schaaf
authors.forename: Nadia
authors.initials: N
authors.lastname: Benkirane-Jessel
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry; D000838:Anions; D002151:Calorimetry / Q000379:methods; D002412:Cations; D004573:Electrolytes; D008422:Materials Testing; D008956:Models, Chemical; D011107:Polylysine / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D011509:Proteoglycans / Q000737:chemistry; D018125:Receptors, Transforming Growth Factor beta / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013431:Sulfates / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000464:Alginates; D000838:Anions; D002412:Cations; D004573:Electrolytes; D011134:Polysaccharides; D011509:Proteoglycans; D018125:Receptors, Transforming Growth Factor beta; D013431:Sulfates; C071736:betaglycan; D011107:Polylysine