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High Pressure Freezer, EMPACT II

Leica Microsystems
Core Imaging Facility

Meta510ocularhigh pressure freezer

The Leica EM PACT2 high pressure freezer with Rapid Transfer System (RTS)  is a high pressure freezing system for vitrifying samples up to 200µm in thickness without the artefacts of chemical fixation.

  • Chemical fixation via diffusion is a slow process that may take  minutes to hours.  Furthermore,  not all cell components will react with fixatives at equal rates, or to equal degrees.  As  a result, some cell components may be lost or rearranged.
  • Physical immobilization of all cell components by ultrarapid freezing has been shown to be superior to conventional chemical fixation at room temperature. 
  • The Leica EM PACT2 makes it possible to observe aqueous biological and industrial samples in their near-native state while preserving  high-resolution information of EM immunocytochemistry, frozen hydrated sections, and freeze fractured samples.
  • The Leica EM rapid transfer system (RTS) allows correlative LM/EM experiments (CLEM), taking a live specimen from a light microscope (e.g. confocal) to freezing in less than 5 seconds.
  • High pressure freezing  may be used to prepare samples for cryoTEM, cryoSEM, for subsequent preparation of freeze-fracture replicas for TEM, and for freeze-substitution. It  has also been successfully applied to non-biological materials such as latex emulsions and inks for cryoSEM examination.

This instrument was purchased with funding from a NIH S10 Shared Instrument grant award.

Specimen prepared by high pressure freezing

muscle, high pressure freezing
HPF/AFS in unicryl

hippocampus, high presssure freezing
HPF/AFS in lowicryl