[3dem] Contamination problem on cryo grids

[Matt Swulius]

I have been using quantifoil grids for both single particle imaging and
tomography.  I do not treat them prior to glow discharge and have never had
problems with achieving good, clean ice.

Matt Swulius
UTHSC - Houston
Neurobiology and Anatomoy

On 9/29/08, Norm Olson <nholson at ucsd.edu> wrote:
>
>
>> Dear Anselm,
>>
>> This looks very much like a hydrophobicity problem. The support is not
>> hydrophilic enough, preventing the water to spread nicely over the film and
>> the holes.
>>
>> I encountered this as a typical Quantifoil problem, since I (and others)
>> noted that there is residual plastic.
>>
>>
> --
> I have been reading this thread with a great deal of interest.  It seems
> like everyone has their own way things should be done but I have not seen
> any studies, I could have missed them, where controlled tests were
> performed.  Carbon films have always had somewhat of a "religion" around
> them but with the manufactured holey carbons it seems like it has gotten
> worse.  As an example, Quantifoils need to be treated to remove the
> manufacturing plastic, to reduce beam-induced charging, to reduce
> contamination, or to make the films more hydrophilic.  Is any of that
> correct? Maybe all of it is correct, who knows.  On the other hand, how many
> people are there out there who don't treat them in solvents at all?  Others
> I have talked with say that the C-flats give more of an even ice thickness
> because they don't have plastic but they still do charge which seems to
> contradict others who say that the plastic causes beam-induced charging.
>  Some people have told me that it is necessary to go through several
> different solvents, others have their one favorite solvent.
>
> Just my observations from the bleacher seats....
>
> Norm
>
> ______________________________________________________________
> Norm Olson
> Cryoelectron Microscopy Facilities Manager
> 1510 Bonner Hall
> Department of Chemistry & Biochemistry, MC-0378
> University of California San Diego
> La Jolla, CA 92093-0378
> nholson at ucsd.edu
> http://cryoem.ucsd.edu
> Cell:  (858)220-2183
> (858)822-6718 - Office; (858)534-5846 - Fax
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