Rapid freezing technique
For obtaining the microstructure of certain tissue or cell, it should be keep close to live condition. Chemical fixation takes several minutes, so it is easy to change the native structure and appear artifact. Rapid freezing technique make possible to fix in almost alive condition by rapidly immersing in cryogenically-cooled medium.
The sample which put on the special grid having small perforations was rapid freezing (water was fleezed as amorphous). Kept the ultracold condition, the grid was inserted in the TEM and observed. The image of right hand indicates in situ structure of peculiar vesicle.