PERMEATION MECHANISM OF DNA-MOLECULES IN SOLUTION THROUGH CUPRAMMONIUM REGENERATED CELLULOSE HOLLOW-FIBER (BMM(TM))

We tried to clarify the membrane permeation mechanism of biopolymer DN A molecule in solution through cuprammonium regenerated cellulose holl ow fiber (BMM(TM)) from the dependence of the permeability of the DNA molecule on the molecular weight (MW), the transmembrane pressure (Del ta P), the total challenge dose, the original concentration of DNA and on the conformation of DNA and from the observation of the shape of t he DNA molecule remaining in the membrane wall. The shape of the DNA m olecule was observed using transmission electron microscopy (TEM), The permeability of DNA molecules decreased with an increase in the MW of the DNA molecule. The MW of the molecule which showed a permeability of more than 0.9 was 1 X 10(6) for the protein with global configurati on and 1 x 10(8) for DNA, The linear protein of the blood coagulation factor VIII combined with von Willebrand factor (F-VIII with VWF) with MW of 2 X 10(7) showed a permeability similar to that of DNA rather t han that of the global protein, When Delta P decreased, the permeabili ty of DNA decreased. Electron microscope observation showed that the D NA molecules were elongated by the shear stress originated in the flow of the solution in pores. We can conclude that: (1) Protein and DNA p ermeate through BMM mainly based on sieving effects. (2) The molecules of DNA and F-VIII with VWF are considered to deform into a string sha pe along the stream line. The chemical structure of a molecule and the shear stress of filtration govern its deformability. The deformation of the molecule contributes to the permeability through BMM, (3) The s ieving effect in working on the permeation of molecules should take in to account their deformability in addition to their geometrical size.