[3dem] Cryo Plunger for cryo EM

[Andreas]

Dear all,

thank you very much for your replies. All your answers were very helpful 
to me.

Best,
Andreas

On 01/28/2015 10:22 PM, Brink Jaap wrote:
> Hi,
>
> There ought to be a set of workshop drawings floating around on the 
> internet for a simple plunger that Tim Baker was using when at Purdue 
> (not sure what he uses now). Anyways, this plunger has al the features 
> of a cheap but very effective plunger you’d need. Comes with footpads 
> release …. If you can’t find them, drop me a note off-line.
>
> Jaap
>
>
>
>> On Jan 28, 2015, at 2:58 PM, benoit.zuber at ana.unibe.ch 
>> <mailto:benoit.zuber at ana.unibe.ch> wrote:
>>
>> Hi Andrea,
>>
>> Depending on what you want to do, you could also have your mechanical 
>> workshop build one plunger for less than hundred euros. It needs an 
>> arm that you can attach tweezers on. The arm needs to be heavy so 
>> that it accelerates well during free fall. It needs to be long enough 
>> to reach a sufficient speed when the grid will touch ethane. And it 
>> needs a release mechanism triggered either by hand or preferably by a 
>> foot pedal if you want to hold the blotting paper with both hands. To 
>> prevent the cryogen to get frozen, you can use a mixture of Ethane 
>> and propane, have small resistance in the ethane container, or have 
>> the container in contact but not fully immersed in liquid nitrogen. 
>> That way ethane is not cold enough to freeze but it is cold enough to 
>> vitrify water. You can check with a thermometer that the temperature 
>> is correct before starting to plunge. We use such a plunger most of 
>> the time and are absolutely delighted. Never a software bug or any 
>> blocked pad, or expensive maintenance contract/Cost. whatever other 
>> problem. It takes a bit of practice at the beginning to get the 
>> feeling for the blotting in order to get the right ice thickness but 
>> after a few sessions you will have it and just like riding a bike, 
>> you will not forget it. Glow discharging the grid in amyl amine 
>> atmosphere is said to help against evaporation and therefore get 
>> reproducible ice thickness (I used to do that but we don't anymore). 
>> Some people will tell you that controlling humidity is absolutely 
>> critical, that the grids will dry otherwise. I do not exclude that 
>> there are cases where humidity control matters but quite often it 
>> does not. If this is a concern you can anyway get a humidifier from 
>> the local supermarket and put the plunger in a rather closed and 
>> chilled hood (taking care though not to ignite ethane)!
>>
>> Best
>> Benoît
>>
>>
>>
>> Le 28 janv. 2015 à 18:22, Andreas <andreas.schmidt at uni-ulm.de 
>> <mailto:andreas.schmidt at uni-ulm.de>> a écrit :
>>
>> Dear all,
>>
>> I am a PhD student at the University of Ulm, Germany and our 
>> Institute wants to buy another cryo plunger. We already bought a 
>> Gatan CP3 and now I was asked to look for other commercial available 
>> cryo plungers. So far I also found the Vitrobot by FEI, the EMS-002 
>> Rapid Immersion Freezer by EMS and the Leica EM GP by Leica. Are 
>> there any other companies selling cryo plungers and would you 
>> recommend them? Or is there anyone who would like sell their old device?
>>
>>
>> Best regards,
>> Andreas
>>
>> -- 
>> Andreas Schmidt
>> Biochemist
>> Institute for Pharmaceutical Biotechnology
>> Ulm University
>> Helmholtzstrasse 8/1
>> 89081 Ulm
>> Germany
>>
>> Tel: +49 (0)731 503 2767
>> Email: andreas.schmidt at uni-ulm.de <mailto:andreas.schmidt at uni-ulm.de>
>>
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>
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-- 
Andreas Schmidt
Biochemist
Institute for Pharmaceutical Biotechnology
Ulm University
Helmholtzstrasse 8/1
89081 Ulm
Germany

Tel: +49 (0)731 503 2767
Email: andreas.schmidt at uni-ulm.de

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