In situ exploration of characteristics of macropinocytosis and size range of internalized substances in cells by 3D-structured illumination microscopy

BACKGROUND: Macropinocytosis can occur in various types of cells and displays multiple functions. However, real-time observation and characterization of the structures of macropinocytosis on the surface of the cell membrane is not yet possible. MATERIALS AND METHODS: Here, we establish a real-time live cell surface imaging method using three-dimensional-structured illumination microscopy. Based on this, observation of the dynamic macropinocytosis process and morphological data of internalized structures on the surface of pancreatic cancer cells were achieved during macropinocytosis. Next, different-sized silica nanoparticles (SiO(2) NPs) were used as the scale for identifying the size range of internalized substances of macropinocytosis in pancreatic cancer cells. RESULTS AND CONCLUSION: Our study not only provides a practical method and more structural data for further investigation of macropinocytosis, but also makes deeper understanding of the cell response toward nanomaterials as well as nanodrugs possible.