Viscoelastic phase separation in biological cells

Abstract Biological phase separation forming membraneless organelles in cytoplasm and nucleus has attracted considerable attention. Liquid-like condensates are often created as spherical droplets. However, various with network-like morphologies, including protein granules, localisation bodies, centrosome assemblies, have recently been discovered cells. Therefore, what controls the morphology of biological is a critical issue but remains elusive. Here, based on knowledge viscoelastic soft matter physics, we propose that difference molecular dynamics between two phases condensate morphology. Small large mobility differences should lead to droplet-like morphologies minority phase, respectively. We show asymmetric partitioning high-molecular-weight unstructured polymers (e.g., messenger RNA) increases dynamic asymmetry form pattern slower which may further be stabilised through inter-polymer binding.