Molecular Weight of Glycogens determined by a Light-scattering Method

Nature ◽  
1952 ◽  
Vol 170 (4323) ◽  
pp. 419-420 ◽  
Author(s):  
B. S. HARRAP ◽  
D. J. MANNERS
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Scattering Method

Comparison of the molecular weights of deoxyribonucleic acids as determined from light scattering and from sedimentation and viscosity

1959 ◽  
Vol 250 (1260) ◽  
pp. 1-21 ◽  
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Large Change ◽  
Scattering Method ◽  
X Rays ◽  
Single Chain ◽  
Molecular Weights ◽  
Upper Limit ◽  
Rough Approximation ◽  
Main Effect

Measurements have been made of (1) light scattering, (2) sedimentation characteristics, and (3) viscosities of identical, well-clarified solutions of a considerable number of preparations of DNA from various sources and under conditions which permit extrapolation of the relevant molecular quantities to zero concentration. In order to increase the range of sizes examined, similar observations have been made with specimens which had been irradiated with 15 MeV electrons or X-rays. It is found that, to a rough approximation, the relation S 0 α [ η ] ⅓ holds for all samples (except those which were heated). There does not appear to be any correlation between M L , the molecular weight determined by light scattering and either [ η ] or S 0 . Values of M η, s from viscosity and sedimentation data have been calculated using the equation of Mandelkern, Flory, Krigbaum & Scheraga (1952) and it was found that with the unirradiated samples these values did not agree with M L , although reasonable agreement was obtained with the irradiated samples. The validity of the calculation of M η, s is discussed. Analysis of the angular variation of the light scattering shows no significant change in the flexibility of the coils upon irradiation, in contrast with the effect of heating where a large change of flexibility occurs. This is in agreement with the hydrodynamic relations given above. Consequently, the differences between irradiated and unirradiated DNA cannot be ascribed to changes of flexibility and the need to use a different model on that account. Since S 0 and [ η ] are both decreased by small doses of radiation, it is difficult to avoid the conclusion that real changes of molecular weight occur, which have not been discovered by the light-scattering method as employed here. It is shown that both for rods and coils there is an upper limit, at finite angles, to the light scattered by a given concentration of polymer, as the size is increased. For a molecule intermediate between a rod and a coil, the limiting curve may appear to have a finite intercept owing to a concealed high curvature at very small angles of scattering. This may set an upper limit to the observed molecular weight for a given degree of flexibility. If the main effect of irradiation is a decrease of molecular weight without marked changes of flexibility, it is difficult to avoid the conclusion either that single chain breaks do not influence the flexibility of the particle or that a high proportion of double breaks occurs.

Determination of the molecular weight of polysaccharides by the light-scattering method

1969 ◽  
Vol 18 (12) ◽  
pp. 2642-2643
Author(s):  
A. K. Dzizenko ◽  
V. D. Sorochan ◽  
T. I. Prudnikova ◽  
Yu. S. Ovodov
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Scattering Method

The Comparative Determination of the Molecular Weight of Rubber by the Methods of Light-Scattering and Osmometry

1956 ◽  
Vol 29 (2) ◽  
pp. 477-484
Author(s):  
B. Dogadkin ◽  
I. Soboleva ◽  
M. Arkhangelskaya
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Natural Rubber ◽  
High Molecular Weight ◽  
Scattering Method ◽  
Comparative Determination

Abstract 1. An account is given of experiments to determine the molecular weight of natural rubber and other high molecular-weight compounds by light-scattering and osmometry. 2. A new design of osmometer for determining molecular weight is described. 3. It is shown that the light-scattering method gives molecular weight values which agree satisfactorily with those given by the osmotic method.

Interaction between Cationic Micelles and Hyaluronan

2016 ◽  
Vol 851 ◽  
pp. 26-31
Author(s):  
Tereza Pilgrová ◽  
Miloslav Pekař
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Zeta Potential ◽  
Inner Core ◽  
Biologically Active ◽  
Scattering Method ◽  
Dynamic Light Scattering Method ◽  
Study Results ◽  
Solubilization Ability

Micelles are particles of colloidal dimension and it is known that in an aqueous phase can solubilize water insoluble molecules (hydrophobic biologically active substances) in their inner core. However surfactants may have adverse effects on biological structures. Association of micelles with suitable bioacceptable molecules (e.g. hyaluronan) may lead to enhance their biocompatibility, decrease the nanoparticles cytotoxicity and also to target to the specific receptors in a human body. In this study, results of the research of electrostatic coating of cationic micelle with hyaluronan are reported. The cationic micelle/hyaluronan complexes were studied using turbidimetry and dynamic light scattering method and were evaluated to determine their structure, average size and zeta potential as a function of the amount of the both component in the system. Turbidimetric titration was chosen as indicator of the loss of intensity of transmitted light due to the scattering effect of particles associated from hyaluronan and surfactant in it. Dynamic light scattering measurement provided information about size distribution and zeta potential during mixing of component. Pilot solubilization experiments were performed to evaluation of stability and solubilization ability of the complexes. Results of turbidimetry revealed that aggregates formation (turbidity increasing) depends especially on hyaluronan concentration while surfactant concentration (above critical micelle concentration) affects interaction insignificantly. Dynamic light scattering experiments indicate that hyaluronan molecular weight has insignificant effect on isoelectric point of the systems. It was found that solubilization ability of the complexes is influenced by molecular weight of hyaluronan.

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