Aggregation of Water Molecules to Phospholipid Head Groups Accompanied with Separation into Water‐ and Polysaccharide‐Rich Phases in Water‐in‐Oil Emulsions

Abstract

AbstractMost organelles, such as the endoplasmic reticulum, are enclosed by biological membranes, although there are some membrane‐less organelles, such as stress granules. The mechanisms by which membrane‐less organelles form and keep their shape are akin to phase separation. Such organelles are located inside cell membranes. However, interactions between cell membranes, phase separations in polymer solutions and lipid head groups, directed towards the inside of the cell have not been investigated. Here we directly observed aqueous hydroxypropyl cellulose (HPC) droplets coated with lipids in mineral oil during an increase in temperature from 10 °C to 65 °C to elucidate the effect of lipid head groups located at the interfaces on dynamic phase behaviours of HPC solutions encapsulated in the cell‐sized droplets. The water molecules inside the droplets are aggregated to the interfaces during an increase in temperature due to the effect of lipid head groups with the separation into water‐ and HPC‐rich phases.