Physicochemical features of ultra-high viscosity alginates

Novel multi-stimuli responsive sodium alginate-grafted-poly(N-isopropylacrylamide) copolymers: II. Dilute solution properties

“…At low pH, Z-average varies in close limits for all copolymers from 200 to 450 nm, with larger differences at c = 0.65 g/dl, while, at high pH, the Z-average takes very different values, from 1800 nm for copolymers with a high AgA content, to 300-600 nm for copolymers with a prevalent content of PNIPAAm. These values agree with those found by (Storz et al, 2009) for the gyration radius if, in a rough approximation, this evaluation was done from the hydrodynamic diameters determined here. This should mean that association is much important at a high AgA content, while PNIPAAm favours a much more packed conformation.…”

“…Therefore, the standard approach is to measure the scattering intensity of the sample, relative to that of a well-described standard with a known Rayleigh ratio (for toluene, at 633 nm, the Rayleigh ratio is 1.3522 × 10 −5 cm −1 ). The dn/dc value of alginate of 0.152 ml/g was taken from the literature of Storz et al (2009) and Martinsen, Skjåk-Brk, Smidsrød, Zanetti, and Paoletti (1991). The radius of gyration (R g ) can be roughly estimated from the hydrodynamic radius (R H ) determined by such experiments, using the shape correction model box for coils: R g = 0.816R H .…”

Asymmetrical flow field-flow fractionation technique for separation and characterization of biopolymers and bioparticles

“…Under these optimal conditions, alginate molecular characteristics, M W 1.8 × 10 5 g mol −1 and R gw 50 nm were obtained by AsFlFFF-MALS-dRI. Storz et al used AsFlFFF-MALS as a complementary technique to SEC in studies of viscous alginates [79]. The results achieved with both these techniques agreed well for the analysis of low molar masses (<2.1 × 10 5 g mol −1 ).…”

Poloxamer 188 as a Supplement to Barium Cross-Linked Ultra-High Viscosity Alginate for Immunoisolation of Transplanted Islet Cells

“…Production of UHV-alginates was performed as described previously [22]. UHV alginates of clinical grade were used for all islet encapsulations (viscosity of a 0.1% wt/vol solution in distilled water was 20-30 mPa·s).…”