What is fluid-phase endocytosis?
Fluid phase endocytosis is a low efficiency, non-specific process that involves the bulk uptake of solutes in exact proportion to their concentration in the extracellular fluid.
Cells continuously take up fluid from their neighbourhood by this process. Unlike other types of uptake, this kind of endocytosis is not preceded by a specific binding to the plasma membrane or concentration of molecules at special sites.
It is considered that cells use this method of fluid uptake for either a surveillance of the surroundings or for the purpose of cleaning the plasma membrane.