Microgravity influence on the instability of phase separation in protein solution

摘要

The influence of cooling and heating rates on the spinodal temperature of lysozyme liquid-liquid phase separation was assessed under microgravity and normal gravity. During both heating and cooling, the mean spinodal temperature was independent of gravity conditions and the rate of temperature change. However, during the cooling process, the spinodal temperature was always lower under microgravity than under normal gravity, whereas the opposite effect was observed under heating. We attribute this phenomenon to the hydrodynamic effect. Under normal gravity, mass transfer occurs by universal convection, but under microgravity it can occur only by diffusion. Because of the relatively small diffusivity of lysozyme molecules, the size evolution of the dense liquid domain was slower under microgravity than under normal gravity.