University of Connecticut |
Polymer Program SeminarPolyelectrolyte-Protein Coacervates: Unusual Biomacromolecular Materials Friday, September 24, 2004 11:00 am , IMS Room 20 Coacervation is the spontaneous formation of a dense liquid phase from a macromolecular solution of poor solvent affinity. In "complex coacervation", desolvation comes from the interaction of complementary macromolecules. Protein-polyelectrolyte coacervates are interesting because the protein is quasi-immobilized at very high concentrations, but still retains enzymatic activity. However, the general subject of coacervates is virtually unexplored due to the lack of systematic studies with modern techniques. Bovine serum albumin forms, with polycations, dense, optically clear and highly viscous coacervate fluids with marked rheological differences when prepared under different conditions and from polycations of different MW. We probed their static structure using light scattering and total internal reflectance fluorescence microscopy, and their dynamics, using rheology, QELS, and fluorescence recovery after photo-bleaching. The results taken together indicate that homogeneous fluid-like domains co-exist with denser and more nearly charge-neutralized domains; these inhibit local protein diffusion and confer transient network rheology. .
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