Gelation Dynamics upon Pressure-Induced Liquid-Liquid Phase Separation in a Water-Lysozyme Solution

J Phys Chem B. 2022 Jun 9;126(22):4160-4167. doi: 10.1021/acs.jpcb.2c01947. Epub 2022 May 20.

Abstract

Employing X-ray photon correlation spectroscopy, we measure the kinetics and dynamics of a pressure-induced liquid-liquid phase separation (LLPS) in a water-lysozyme solution. Scattering invariants and kinetic information provide evidence that the system reaches the phase boundary upon pressure-induced LLPS with no sign of arrest. The coarsening slows down with increasing quench depths. The g2 functions display a two-step decay with a gradually increasing nonergodicity parameter typical for gelation. We observe fast superdiffusive (γ ≥ 3/2) and slow subdiffusive (γ < 0.6) motion associated with fast viscoelastic fluctuations of the network and a slow viscous coarsening process, respectively. The dynamics age linearly with time τ ∝ tw, and we observe the onset of viscoelastic relaxation for deeper quenches. Our results suggest that the protein solution gels upon reaching the phase boundary.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gels / chemistry
  • Kinetics
  • Muramidase*
  • Viscosity
  • Water* / chemistry

Substances

  • Gels
  • Water
  • Muramidase