Equilibrium scaling of phase separated elastin-like polypeptides for engineered condensates.

Area of Science:

• Biophysics
• Polymer Science

Background:

• Elastin-like polypeptides (ELPs) exhibit tunable liquid-liquid phase separation (LLPS).
• Understanding the thermodynamics of ELP LLPS is crucial for designing functional biomolecular condensates.
• Existing models may not fully capture the complex interplay of factors influencing ELP phase behavior.

Purpose of the Study:

• To experimentally determine the Flory-Huggins interaction parameter for phase-separating ELP systems.
• To develop a semi-empirical model predicting ELP phase equilibria and critical temperatures.
• To establish a predictive framework for engineering ELP-based condensates and coacervates.

Main Methods:

• Experimental determination of the Flory-Huggins interaction parameter.
• Fitting experimental data to a semi-empirical model.
• Temperature-driven turbidity measurements to assess phase separation kinetics and equilibrium.

Main Results:

• The developed model quantitatively describes temperature and chain length dependence of ELP phase separation.
• Phase equilibria and critical temperatures in VPGVG pentameric repeat ELP systems were accurately predicted.
• Turbidity measurements confirmed that temperature translation can recapitulate equilibrium phase behavior.

Conclusions:

• The study provides a predictive tool for ELP LLPS, integrating experimental and theoretical approaches.
• This model enables precise engineering of ELP condensates and coacervates by tuning parameters like pentamer number, temperature, and concentration.
• The findings advance the design principles for stimuli-responsive biomaterials and intracellular phase separation mimics.