High pressure freezer
Samples for TEM can be pocessed either by means of chemical fixation or by cryofixation. Cryofixation stabilizes and fixes the specimen by the physical process of freezing. The main advantages consist of a fixation time of the order of milliseconds and a simultaneous immobilisation of all cellular components. Different cryofixation methods exist that vary in the depth of good freezing - that is in a way that ice crystals are not formed or are so small that cellular structures are not distorted. Among these methods, high pressure freezing is the most powerful cryofixation method for thicker samples and can be realized at the MPIPZ with the Leica HPM100 high pressure freezing machine.