UCST Behavior of Guanidinium-Containing Polyelectrolyte Solutions: Thermodynamic Study
발표자
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초록
내용
Guanidinium (G) group of arginine has been considered as a strong determinant of protein phase separation. Recently, we reported the G-containing polyelectrolyte solutions undergo salt-induced liquid-liquid phase separation (LLPS) without oppositely charged polyelectrolytes, also known as simple coacervation, and exhibit upper critical solution temperature (UCST) phase behavior in aqueous media. In this work, UCST phase behavior of G-containing polyelectrolyte solutions was characterized by transmittance, small-angle neutron scattering (SANS) and light scattering measurements, resulting in a phase diagram. The thermodynamic parameters including spinodal, critical and θ temperatures increase nearly linearly with increasing overall salt concentration. These results reflect that solvent quality for G-containing macromolecule solutions is precisely regulated by monovalent salt concentration. Our findings provide thermodynamic understanding of G-related protein phase separation and fundamental implications to design thermo- and saline-responsive materials.