Antonov, Y.A., Wolf, B.A.

"Phase behavior of aqueous solutions of bovine serum albumin in the presence of dextran, at rest and under shear"

Biomacromolecules 2006, 7, 1562-1567.

Abstract: The demixing conditions for aqueous solutions of bovine serum albumin (BSA, fractionV) and for joint solutions of BSA plus dextran (DEX, M w = 2000 kg/mol) were determined by turbidimetric measurements as a function of composition, temperature and shear rate. Aqueous solutions of BSA phase separate upon heating. Within the region of BSA concentrations between 0.05 and 32 wt% the demixing temperature, T1, falls from ca. 65 C to an almost constant value of 45 C. Adding DEX to the BSA solutions reduces the homogenous region of the mixture drastically where the amount of DEX required to lower T1 to 25 C decreases rapidly as the concentration of BSA is raised. Experiments concerning the influences of shear have been performed for the ternary system up to 500s-1. They demonstrate that the content of dextran determines the sign of the effect. At low DEX concentrations the mechanical field favors the homogeneous state (shear induced mixing), whereas the opposite effect (shear induced demixing) is observed at high DEX concentrations. Possible reasons for this observation are discussed.

preprint number: 275