Vitrobot procedure
The VitrobotTM (Vitrification Robot) is a fully PC-controlled device for vitrification (= rapid cooling) of aqueous samples
Before starting
fill a dry 5 L tank with liquid nitrogen
label grid boxes with the name of the experiment
check plasma cleaner is reserved
Assemble the necessary tools:
EM_grids grids are available and present in sufficient number
all part of the coolant container (make sure that they are dry)
both vitrobot tweezers, big tweezer and blot paper clipping
Starting up the vitrobot
Set blotting process parameters
This step is done on the control panel, in the “options” page
1. 'blot total' needs to be '1' for blotting to occur
2. check 'Humidifier off during process' and 'Skip grid transfer' in the miscellaneous' side bar
3. Optional : set your desired blot time, force blot and waiting time (o for unsupported condition )
Set humidity and temperature parameters in climate chamber
This step is done on the control panel, in the “console” page
Mounting the filter papers
IMPORTANT always wears gloves
place blot papers onto the blotting pads with clipping ring
support the blotting arms during assembling to prevent damage to the arms
load grids inside the plasma cleaner
From now on IMPERATIVELY wears gloves
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5. close the door to prevent dust contamination inside the chamber
6. place EM_grids inside the metallic drawer
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8. put back in place the metallic drawer inside the chamber
9.
close the door
a. be sure the seal is in place and clean (see part.7)
b. move the lid around its axis to bring it over the opening of the chamber
c. unlock the rod by pushing the button
d. gently allow the lid to slide down
10. press VACCUM to bring the chamber under vaccum
11. if not yet done on vitrobot, enable the humidity switchbox to start
Assemble different part of the coolant container as pictured below
Cooling down the coolant container
1. Pour LN2 into both central ethan cup (A) and outer part (E) to faster the cooling
2. Wait for complete evaporation of the remaining nitrogen in the central part
3. up to now continously fill the outer part to maintain the Nitrogen level
4. wait 10 to 15 min for system to equilibrate
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7. then remove the spindle (C)
Solidified ethan makes stick together the spindle and the ethan cup.
Thawing the frozen ethan by placing the second ethan cup on the spindle for 10sec is the more careful way to remove it with a big tweezer
8. place grid box into the grid box platform (B)
plasma clean grids
2. set desired plasma cleaning parameters :gas mixture/gas flow power
commonly settings 80-20-0 are used
The setup TABS store preset parameters
settings 80-20-0 corresponds to Gas mix Oxy/Ar : 80/20, power 34%
Gas Mix and plasma TABS show preset values
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4. press START to apply plasma on grids
5. press Vent Lock to bring the chamber under atmospheric pressure
6. Open the chamber
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8. close the door to prevent dust contamination inside the chamber
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10. put the glass slide in a closed crystallizer to transfer safely grids to vitrobot bench
11. load or not new grids in the drawer and close it
12. put back in place the closed drawer on the support table
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14. put back in place the metallic drawer inside the chamber
Everything is ready for plunge freezing sample:
climate chamber is equilibrated in temperature and humidity.
Filter paper are mounted
ethane is liquefied
Grids are freshly plasma cleaned
Start freezing at the vitrobot
1. check that the correct freezing parameters are entered
2. click on “place new grid” to bring in loading position the plunge rod
3. Lock a Glow discharged grid on tweezers
4. then fix the tweezers onto the plunge rod
5. press on “continue” to bring up the tweezers into the blotting chamber
6. place the container onto the ethane lift
7. press on to lift it
8. click on “process”
9. apply sample to grid
10. click on “continue” to blot and plunge
11. carrefully detach tweezers from the plunge rod
12. By maintaining the grid inside the ethan cup, place the coolant container on the table
13. transfer grid to the grid position
14. Dry tweezers
15. then repeat sequence 1-14 for all glow discharged grids