Description
The process of liquid-liquid phase separation (LLPS) has been explored in polymer physics and colloidal science, and recently, researchers have studied this process to better understand intracellular organization. LLPS is the process by which a liquid mixture will separate into two fluid phases. Currently, many research labs are working to understand how and why certain cellular organelles are liquid bodies that are the result of phase separation. Investigations of how the cell uses phase separation to organize and compartmentalize has demonstrated a wealth of biological implications. We experimentally study the process of de-mixing in a model system in order to define better ways of analyzing and characterizing the physical properties of the two fluid phases. Our experiments utilize the following optical methods: phase contrast microscopy for video analysis of droplets merging to determine capillary velocity; fluorescence recovery after photo-bleaching (FRAP) to determine the diffusion coefficient; particle tracking to determine viscosity; and confocal z-scans to determine the density difference between two phases. By assessing methods to study the physical features of these droplets, like surface tension, viscosity and density, optimal methods can be applied to study membrane-less organelles assembled in cells via LLPS.
Characterizing Liquid-Liquid Phase Separation
The process of liquid-liquid phase separation (LLPS) has been explored in polymer physics and colloidal science, and recently, researchers have studied this process to better understand intracellular organization. LLPS is the process by which a liquid mixture will separate into two fluid phases. Currently, many research labs are working to understand how and why certain cellular organelles are liquid bodies that are the result of phase separation. Investigations of how the cell uses phase separation to organize and compartmentalize has demonstrated a wealth of biological implications. We experimentally study the process of de-mixing in a model system in order to define better ways of analyzing and characterizing the physical properties of the two fluid phases. Our experiments utilize the following optical methods: phase contrast microscopy for video analysis of droplets merging to determine capillary velocity; fluorescence recovery after photo-bleaching (FRAP) to determine the diffusion coefficient; particle tracking to determine viscosity; and confocal z-scans to determine the density difference between two phases. By assessing methods to study the physical features of these droplets, like surface tension, viscosity and density, optimal methods can be applied to study membrane-less organelles assembled in cells via LLPS.