Leica EM ICE High Pressure Freezer

High pressure freezing with the possibility of light and electrical stimulation


Show answer For which applications / fields of research would I typically use the Leica EM ICE?

Biology Research: Cell biology, Structural biology, Optogenetics, Neurobiology.

Industrial Research: Food, Cosmetics, Composite Materials. 

Show answer How long is the recovery time between the freezing cycles?

1 minute only.

Show answer How long does it take from loading the sample in the specimen carrier to having it frozen?

1 second only.

Show answer How much LN2 do I need for using the instrument a whole day?

30 liter LN2 daily consumption are needed – including cooling down

Show answer Do I need any synchronization fluids?

No - no alcohol or additional synchronization fluids are used in this system.

Show answer How long is the cooling down time?

20 minutes.

Show answer Do I have to fill the LN2 Dewar completely in order to operate the instrument?

No, the instrument can be operated with minimum 8 – 10 liter of LN2 for cooling down.

Show answer How does high pressure freezing with Electrical Stimulation work?

The electricity required for the stimulation of 6 mm sample is stored in capacitors built-in the specially designed middle plate. This middle plate is a PCB (printed circuit board) which can be charged with electricity. The electricity stored in the capacitors can be selectively discharged inside of the high pressure chamber.

The release of electrical current is induced by a light-sensitive switch incorporated in the middle plate. The switch is activated by the integrated blue light module and controlled by the software. The plate holds capacity of 50μF and 10V that can be discharged to the sample completely or in pulses with millisecond accuracy. The actual voltage will depend on the duration of the experiment, as the reduction of voltage follows the exponential “decay curve” for capacitor discharge.

Show answer Why high pressure freezing with Electrical Stimulation?

Membrane trafficking events at neuronal synapses are the basis of every memory, every emotion. Understanding this highly dynamic event is anything but trivial. The combination of well-established electrophysiology research methods and the technology that allows for millisecond precision in sample preservation is the only tool that may bring the revelation of many unanswered questions such as “How are synaptic vesicles recycled?”

Applying electric field across neural or muscle tissue can trigger neuronal activity  by initiating an action potential and release of a neurotransmitters.  The conduction of action potential is extremely fast process it can exceed 100 m/s, which is one-third the speed of sound.

The pursuit for ever more precise imaging and understanding of  action potentials required the development of new experimental methods.  The combination of electrical stimulation and high pressure freezing allows for the capture of neurons in motion a highly accurate snapshot  under physiological conditions.

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