Elastic and quasielastic light scattering studies on the branching characteristics of dextrans

Abstract

The influence of branching on the radius of gyration and the hydrodynamic radius of dextran macromolecules was studied by elastic and quasielastic light scattering (ELS and QELS). The hydrodynamic radius is more sensitive to low levels of branching than the radius of gyration. At higher branching levels a saturation of the hydrodynamic radius r, is observed, while the radius of gyration 'G still changes distinctly. The ratio rG/rh proves to be a measure of the flexibility of the macromolecules; the latter is increasing with molecular weight for short linear chains and is decreasing with increasing degree of branching. Measurements were carried out in water (thermodynamically good solvent) and in ethylene glycol (under theta conditions) on four series of dextran fractions having rather narrow molecular weight distributions.

Interactions in mixed cationic surfactants and dextran sulfate aqueous solutions

“…Slight reducing of polyelectrolyte chains length is compensated for by increasing the molar mass of complex due to the bound surfactant monomers, leading to an increase in the mean particle size. The first particles, which appear upon surfactant addition, exhibit the mean particle size close of 16 nm, which is close to that of polyelectrolyte itself (the DxS molecules in water resemble a rod with the radii of the cylindrical macroion a ≈ 0.4 nm [6], with hydrodynamic radius R h = 15.8 nm [48]). Therefore it is reasonable to attribute it to an intrapolymer complex.…”

Effects of dextran polydispersity on red blood cell aggregation

“…B 512 F dextrans present about 95 % 0~ (1-6) linkages in the main and side chains, the remaining 5 % a (1-3) linkages are starting points of branches [14]. Recently, Fahner [15] has measured the radius of gyration of almost linear dextran. From these results, the exponent v relating the radius of gyration to the Z average MW is equal to 0.52.…”

Cytosolic Uptake of Large Monofunctionalized Dextrans

“…We sought to examine if there were any inherent structural differences in conjugate 2 relative to other dextrans that might cause cell penetration. Physical characterization of dextrans typically entail determining their average hydrodynamic radius (which is correlated with molecular mass) and branching ratios. ,−, We were especially interested in deviations among the parent dextrans in our conjugates ( D1 – D3 ) as well as an unconjugated 100 kDa dextran ( D4 ). We first determined the hydrodynamic radii, which agreed closely with standard parameters for dextrans .…”