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

The interaction parameter of the Flory-Huggins free-energy of two phase separating components was experimentally determined and fit to a semi-empirical model. This model captures the temperature and chain length dependence, quantitatively describing phase equilibria and critical temperatures in elastin-like polypeptide systems of <i>VPGVG</i> pentameric repeats. We show temperature driven turbidity measurements of phase separation will recapitulate equilibrium through a simple temperature translation. This integrates both experiment and theory of liquid-liquid phase separation, offering a predictive tool for the ability to engineer ELP condensates and coacervates by tuning number of pentamers, temperature and concentration.