Physicochemical features of ultra-high viscosity alginates.
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.
Storz
Henning
H
Institute for Technical and Macromolecular Chemistry, University of Hamburg, Hamburg, Germany.
Müller
Kilian J
KJ
Ehrhart
Friederike
F
Gómez
Ivan
I
Shirley
Stephen G
SG
Gessner
Petra
P
Zimmermann
Gertraud
G
Weyand
Esther
E
Sukhorukov
Vladimir L
VL
Forst
Thomas
T
Weber
Matthias M
MM
Zimmermann
Heiko
H
Kulicke
Werner-Michael
WM
Zimmermann
Ulrich
U
D000464:Alginates / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D000459:Phaeophyceae / Q000737:chemistry; D012542:Scattering, Radiation; D014783:Viscosity
D000464:Alginates