[3dem] C-flats

[James Riches]

Hi Thorsten,
	We had problems with a batch of C-flats that we got late last year. The 
carbon broke apart if we used the normal glow discharge process that we 
used for earlier batches and we had to greatly reduce the time that we 
used to get most of the squares intact after plunging. Our carbon on 
these grids also disintegrated under a focused beam. We also observed a 
greater incidence of beam induced charging on these samples. You might 
want to contact the people at Protochips. They seem to be aware of this 
'thinning' problem with the carbon and they could probably tell you if 
your batch might be affected.

Cheers,
Jamie


Thorsten Mielke wrote:
> Dear all,
> 
> we are trying to vitrify some small proteins on c-flat grids (type 
> CF-2/4-4C) using a Vitrobot from FEI. However, after plunge-freezing, 
> the carbon film is heavily destroyed. Additionally, we find only a few 
> good holes on the remaining intact meshes. The carbon film also seems to 
> be extremely fragile and easily disrupts upon focusing (300 kV, 155kx 
> Polara). The grids seem to be OK (with or without glow-discharching) 
> until plunge-freezing. We varied the blotting offset at the Vitrobot to 
> play with the blotting force, no success.  Did you observe similar 
> problems with C-flats? Any idea how to prevent the carbon film from 
> breaking?
> 
> Thanks
> 
> Thorsten
> 
> 
> 
> 

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Jamie Riches
Briggs Group
European Molecular Biology Laboratory
Heidelberg, 69115
Germany

Ph: +49 6221 387195
Fax: +49 6221 387519
Email: riches at embl.de

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