title: Physicochemical features of ultra-high viscosity alginates.
abstract: The physicochemical characteristics of the ultra-high viscosity and highly biocompatible alginates extracted from Lessonia nigrescens (UHV(N)) and Lessonia trabeculata (UHV(T)) were analyzed. Fluorescence and (1)H NMR spectroscopies, viscometry, and multi-angle light scattering (MALS) were used for elucidation of the chemical structure, molar mass, and coil size. The sequential structures from NMR spectroscopy showed high guluronate content for UHV(T), but low for UHV(N). Intrinsic viscosity [eta] measurements exhibited unusual high values (up to 2750 mL/g), whereas [eta] of a commercial alginate was only about 970 mL/g. MALS batch measurements of the UHV-alginates yielded ultra-high values of the weight average molar mass (M(w) up to 1.1x10(6) g/mol) and of the z-average gyration radius (R(G)(z) up to 191 nm). The M(w) and R(G)(z) distributions of UHV-alginates and of ultrasonically degraded fractions were determined using size exclusion chromatography combined with MALS and asymmetrical flow-field-flow fractionation. The M(w) dependency of [eta] and R(G)(z) could be described by [eta]=0.059xM(w)(0.78) and R(G)(z)=0.103xM(w)(x). (UHV(N): x=0.52; UHV(T): x=0.53) indicating that the monomer composition has no effect on coil expansion. Therefore, the equations can be used to calculate M(w) and R(G)(z) values of UHV(T)- and UHV(N)-alginate mixtures as used in immunoisolation. Furthermore, the simple and inexpensive capillary viscometry can be used for real-time validation of the extraction and purification process of the UHV-alginates.
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Hamburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Storz
authors.forename: Kilian J
authors.initials: KJ
authors.lastname: Müller
authors.forename: Friederike
authors.initials: F
authors.lastname: Ehrhart
authors.forename: Ivan
authors.initials: I
authors.lastname: Gómez
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Shirley
authors.forename: Petra
authors.initials: P
authors.lastname: Gessner
authors.forename: Gertraud
authors.initials: G
authors.lastname: Zimmermann
authors.forename: Esther
authors.initials: E
authors.lastname: Weyand
authors.forename: Vladimir L
authors.initials: VL
authors.lastname: Sukhorukov
authors.forename: Thomas
authors.initials: T
authors.lastname: Forst
authors.forename: Matthias M
authors.initials: MM
authors.lastname: Weber
authors.forename: Heiko
authors.initials: H
authors.lastname: Zimmermann
authors.forename: Werner-Michael
authors.initials: WM
authors.lastname: Kulicke
authors.forename: Ulrich
authors.initials: U
authors.lastname: Zimmermann
mesh_terms: D000464:Alginates / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D000459:Phaeophyceae / Q000737:chemistry; D012542:Scattering, Radiation; D014783:Viscosity
chemical_list: D000464:Alginates