Smart Protein Refolding System Based on UCST-Type Ureido Polymers.

We have reported that ureido polymers exhibit upper critical solution temperature (UCST)-type phase behavior in solution, which is the opposite of lower critical solution temperature (LCST)-type behavior. Furthermore, UCST-type ureido polymers undergo liquid-liquid phase separation (LLPS) upon cooling rather than the liquid-solid phase transition of the typical LCST-type polymers. In this study, ureido polymers with hydrophobic groups were prepared to evaluate the effects of cooling-induced LLPS of UCST-type polymers on refolding of proteins.

Rational Design of UCST-type Ureido Copolymers Based on a Hydrophobic Parameter.

Thermoresponsive polymers exhibiting upper critical solution temperature (UCST)-type behavior under physiologically relevant conditions have potential as biomaterials. The phase separation temperature ( T) of the UCST-type polymers can be increased by copolymerization with hydrophobic comonomers. Quantitative index parameters that could be used to rationally tune the T are lacking, however.

Design of a Tunable Self-Oscillating Polymer with Ureido and Ru(bpy) Moieties.

An upper critical solution temperature (UCST)-type self-oscillating polymer was designed that exhibited rhythmic soluble-insoluble changes induced by the Belousov-Zhabotinsky (BZ) reaction. The target polymers were prepared by conjugating Ru(bpy) , a catalyst for the BZ reaction, to ureido-containing poly(allylamine-co-allylurea) (PAU) copolymers. The Ru(bpy) -conjugated PAUs exhibited a UCST-type phase-transition behavior, and the solubility of the polymer changed in response to the alternation in the valency of Ru(bpy) .