ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 1, pp. 160 !161. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + S.O. Eshbekova, A.A. Kholmuminov, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 1, pp. 164 !165.
Structuring of Fibrillar Proteins in Electrodialysis
of Ions in a Shear Flow
S. O. Eshbekova and A. A. Kholmuminov
Dzhizak Polytechnic Institute, Dzhizak, Uzbekistan
Institute of Polymer Chemistry and Physics, Academy of Sciences of the Republic
of Uzbekistan, Tashkent, Uzbekistan
Received October 23, 2007
Abstract-Possibility of using electrodialysis for controlling the content of ions in structuring of silk fibroin
in a shear flow was studied.
Fibrous wastes of fibrillar proteins can be proc-
essed into polymeric materials in solutions in the
presence of ions of salts, acids, and alkalis . How-
ever, presence of ions in solution hinders formation of
bonds between macromolecules when a three-dimen-
sional structure of proteins is formed in a flow. The
ions can be subsequently removed from the solutions
by electrodialysis, and application of this technique is
of practical interest .
The present study was concerned with the effect of
electrodialysis of salt ions on the structuring of fib-
rillar proteins in a shear flow for the example of the
fibroin of real silk.
An installation for carrying out the experiments was
fabricated on the basis of the Rheotest-2 instrument
(Germany) with a cylinder3cylinder working unit
(Fig. 1). A cylindrical cellulose hydrate membrane (2)
was mounted between carbon electrodes (1, 1`) fixed
in parallel in a glass cylinder. A glass cylinder
(3) rotated by electric motor (M) was coaxially
mounted within the membrane cylinder. The spacing
between the cylinders, filled with a solution of silk
fibroin (4), was about 3 mm. A polarization beam was
passed through this space in order to determine the
macromolecule orientation factor b in the flow with
a polarization microscope (PM):
where Dn is the current birefringence, and Dn
maximum possible birefringence .
The direction in which ions 6 move across the
membranes toward the electrodes submerged in the
dialyzate coincides with the direction in which protein
molecules are deformed by the centrifugal force F
r (V is the volume of the solution; r, its den-
sity; w, angular rate of rotation; and r, distance from
the rotation axis).
The fluidity r
of the fibroin solution was found by
the Margules formula , with the rate of cylinder
rotation controlled by the electric motor
is the solution viscosity; h, cylinder height;
)/2, hydrodynamic cell parameter (R
the radius of the inner glass cylinder, and R
, that of
the outer membrane cylinder); b, distance between the
cylinders; and M = rF
Fig. 1. Schematic of electrodialysis of ions in a shear flow
of ion-containing solutions of fibrillar proteins. For ex-
planations, see text.