Pinocytosis involves the invagination of the cell membrane to form vesicles that internalize extracellular fluid. This process is subdivided into two main types: micropinocytosis and macropinocytosis. Micropinocytosis involves small vesicles and is typically clathrin-mediated, whereas macropinocytosis forms larger vesicles and is actin-dependent. The choice of pathway can be influenced by the physical and chemical properties of the nanoparticles being introduced.
