Transfer Of Vitrified Grid - Thermo Scientific Vitrobot Mk IV User Manual

Chapter | Operating Instructions
The blotting procedure is immediately followed by injection of the tweezers with grid into the
liquid ethane or propane. The only delay between blotting and plunge freezing is determined
by the drain time that can be set in the 'Options' page of the UI and the time required for
removing the shutter from the hole in the climate chamber. The actual plunging mechanism is
mediated by a pneumatics (air pressure) at the central axis combined with the gravitational
force.
After plunge freezing both the liquid coolant container and the tweezers with grid are
automatically and simultaneously lowered while keeping the grid inside the liquid ethane. This
prevents any contamination of the freshly frozen sample.

3.9 Transfer of Vitrified Grid

After vitrification the frozen grid must be transferred into a storage box or cryo holder.
With the semi-automated grid transfer default active, the grid is automatically transferred from
the liquid ethane/propane towards the liquid nitrogen atmosphere. Prior to positioning the grid
into the grid box, the tweezers must be carefully disconnected from the central axis. To make
the grid transfer more convenient, the coolant container should be lifted from the support ring
and positioned next to the Vitrobot.
It is recommended to remove the access of liquid ethane – that may be capillary present in
the groove of the tweezers that hold the grid – with some filter paper. The anti-contamination
ring, which floats on the liquid nitrogen, creates a cold gaseous atmosphere which facilitates
the transfer and minimizes possible ice contamination on the grid. The outer ring contains a
circular storage grid box for four grids underneath a layer of liquid coolant gas.
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PN 103261 | Revision D | 23-Oct-2019
User Manual
Page 28