Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster: Colloids and Complex Fluids
CPP 12.12: Poster
Montag, 7. März 2016, 18:15–21:00, Poster B2
Investigations on the kinetics of Liquid-Liquid Phase Separation and dynamic arrest in protein systems — •Stefano Da Vela1, Fajun Zhang1, Alessandro Greco1, Michael Sztucki2, Zhendong Fu3, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen — 2ESRF, Grenoble, France — 3JCNS, Garching, Germany
Aqueous solutions of bovine γ-globulin in the presence of polyethylene glycol, and of bovine serum albumin in the presence of Yttrium(III),are studied in comparison as two widely differing protein systems, both featuring Liquid-Liquid Phase Separation (LLPS). While in bovine γ-globulin LLPS is determined by an isotropic attractive depletion interaction, in bovine serum albumin LLPS is triggered by Yttrium cations activating a directional "patchy" attractive interaction. Notably, while for γ-globulin the LLPS boundary has an upper critical solution temperature, albumin features a lower critical solution temperature behaviour. The experiments focus on the kinetics of phase separation in samples at high protein volume fraction, driven in the two phase regime by a rapid temperature variation. The development of μm size structures is followed through the stages of the phase separation by state-of-the art time resolved Ultra Small Angle X-Ray Scattering (USAXS) and time resolved Very Small Angle Neutron Scattering (VSANS), complemented by optical microscopy. The time evolution of the characteristic length and the analysis of the scattering profiles allow for a comparison between the two systems and for interpretation of the data relative to the later stages of the phase separation.