Regensburg 2019 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Poster Session I
CPP 17.26: Poster
Monday, April 1, 2019, 17:30–19:30, Poster B1
Dynamics upon arrest in protein solutions with LCST phase behavior — •Anastasia Ragulskaya1, Nafisa Begam1, Anita Girelli1, Hendrik Rahmann2, Fajun Zhang1, Christian Gutt2, Thomas Zinn3, and Frank Schreiber1 — 1Universitat Tubingen — 2Universitat Siegen — 3ESRF
Dynamically arrested states can occur as a result of an interplay of liquid-liquid phase separation (LLPS) and glass formation in protein and colloidal systems. We use a model system of bovine serum albumin (BSA) with YCl3 which shows LLPS and a lower critical solution temperature (LCST) phase behavior [1]. Following a temperature jump (T-jump) the protein-rich phase undergoes an arrested spinodal decomposition. Growth kinetics of a characteristic length as a function of time, observed using ultra-small angle X-ray scattering, shows a transition to an arrested state at high temperatures. Here, we investigate the dynamics of LLPS approaching the arrested state using X-ray photon correlation spectroscopy (XPCS). The analysis of two-time correlation functions obtained from XPCS shows compressed exponential dynamics in the temperature range
∼ 45 −50 ∘C, with further transfer to stretched dynamics beyond 52.5∘C. This may be treated as a transition from a superdiffusive to an intermittent dynamics of a glassy state. The dramatic jump of the characteristic relaxation time τ constant with q indicates the emergence of an arrested state above 52.5∘C, but below thermal denaturation (60∘C). For each T-jump, τ first increases, then becomes faster again before the system gets arrested.
O.Matsarskaia et. al., Phys. Chem. B, 120, 5564, 2016.