Size Scaling of Condensates in Multicomponent Phase Separation

Area of Science:

• Biophysics
• Cell Biology
• Soft Matter Physics

Background:

• Intracellular size scaling, constant proportionalities between cells and organelles, is widely observed but poorly understood.
• The underlying mechanisms and environmental modulations in multicomponent systems remain unclear.

Purpose of the Study:

• To investigate the size scaling of membrane-less condensates.
• To elucidate the role of liquid-liquid phase separation and environmental factors in condensate size regulation.

Main Methods:

• Utilized microdroplet-encapsulated minimalistic condensates formed by droplet microfluidics.
• Employed mean-field theory to model condensate behavior.
• Conducted experiments across various condensate systems.

Main Results:

• Demonstrated that condensate size scaling is an intrinsic characteristic of liquid-liquid phase separation.
• Confirmed size scaling with a generic lever rule from mean-field theory and experimental observations.
• Showed that condensate-to-microdroplet scaling ratio is influenced by solute and salt concentrations, aligning with theoretical predictions.
• Identified a noise buffering mechanism where condensates maintain constant volumes by regulating small molecule dynamics at interfaces.

Conclusions:

• Condensate size scaling is a fundamental aspect of liquid-liquid phase separation.
• Environmental factors significantly impact condensate size regulation.
• A novel noise buffering mechanism involving dynamic molecular rearrangement contributes to volume homeostasis in condensates.