Freeze Fracture Direct Imaging:A New Freeze Fracture Method for Specimen Preparation in Cryo-Transmission Electron Microscopy

摘要

In this páper,we present a new freeze fracture method for specimen preparation for transmission electron microscopy frozen samples.We call it freeze fracture direct imaging (FFDI) because it is a hybrid of conventional freeze fracture electron microscopy (FFEM) and cryo-transmission electron microscopy (cryo-TEM),combining elements of the fracture technique with direct imaging.Like in FFEM,the sandwich method is used to prepare the sample in a protected fashion.However,after the sample is vitrified and fractured,it is not shadowed but directly imaged.The new technique avoids some experimental artifacts produced by the blotting procedu?e in conventional cryo-TEM.It relies,though,on occasional fractures transparent to the electrons.The advantageous features are demonstrated by a comparison between conventional cryo-TEM and FFDI micrographs of vesicular solutions.The second outstanding advantage over conventional cryo-TEM is the fact that it is now possible for the very first time to directly image oil-rich mixtures films which normally would dissolve in the cryo-medium ethane.Micrographs of pure oil and of oil-rich microemulsions clearly prove the reliability of the FFDI technique as well as its enormous potential.