Laser light scattering study of nanostructures - dipole clusters formation in
the solutions containing heavy metal ions.
A.V. Boiko, G.P. Petrova, Yu.M. Petrusevich, D.I. Ten, V. K. Scheslavskii
Physical Department Lomonosov Moscow State University,119899, Russia,
7-(095) 939-10-88, Fax. (095) 932-88-20, e-mail: petrova@phys.msu.su
The conditions of the formation and destruction of macromolecular
structures ( with radii about 50-100 nm) in water solutions of protein molecules in
the presence of some metal ions with the large ion radius were investigated by
Rayleigh–Debye (RDLS) light scattering and photon-correlation spectroscopy
(PCS).
We used the salts of metals in the free ( Pb acetate, Cd sulfate, etc. ) and in
chelate form (EDTA- Eu).
The formation of macromolecular protein clusters in water solutions in the
presence of some heavy ions were studied at different pH, concentrations of
components and temperature of the solutions.
RDLS – method allows to obtained the static parameters data – effective
mass and interaction coefficient of scattering particles in the solutions. With the
help of PCS we can obtained the diffusion coefficient of the particles and its
hydrodynamic radii. In our experiments we used such proteins as albumins and
collagen.
By both of this methods we find the increase of mass and hydrodynamic
radius values of the scattering particles in investigated systems in comparison with
molecular mass of proteins. This increasing have nonlinear dependence from pH
solution with Max near of the isoelectric point of the proteins.
For collagen the sharp increasing of hydrodynamic radii with change of
pH and concentration protein in solution was obtained. This phenomenon can be
connected probably with formation of the net structure when the concentration of
collagen exceed the critical value.