[3dem] Interpretation of strange objects in a cryo-EM sample

[Ingo Lieberwirth]

Dear James,

we had also observed pretty much the same objects in several liposome 
samples. The ice was not the best in the images but they clearly show 
very similar Objects. Unfortunately, I cannot reveal any details about 
the composition or production of the sample.  My first guess, based on 
the bright contrast, was that we might be dealing with 
surfactant-stabilized air bubbles here. which could be due to an excess 
of surfactant coupled with too much ultrasonic / shear energy. In any 
case, these objects deform on contact with the edges of the holes, 
indicating some interaction with surfaces.
However, we did not pursue the matter further at that time because we 
had no further interest in identifying these objects. But it is 
definitely not beam damage.
Hope I could help at least a little bit.

With kind regards / Mit freundlichen Grüßen_

*Dr. Ingo Lieberwirth*

Head of Electron Microscopy Core Facility Department of Physical 
Chemistry of Polymers Max Planck Institute for Polymer Research 
Ackermannweg 10 55128 Mainz Germany Tel. +49 6131 379 580 FAX +49 6131 
379 100 https://urldefense.com/v3/__http://www.mpip-mainz.mpg.de/physical_chem_of_polymers__;!!Mih3wA!BZT1FSgZyY8B6pohwx01MO-OZQZ5nYeQ5oeM8uzt_2ED7wP7hth3omyHRxkSxRqrMj6qNJSlTPy_cE6Gj1lx2Ir0fC3C$ 

Am 13.04.2023 um 15:48 schrieb Kizziah, James:
>
> Hi all,
>
> We have imaged a cryo-EM sample presumed to contain micelles and 
> observed the large, white objects full of/covered with junk shown in 
> the attached images. Our best guess is that these are (or were) the 
> micelles and have been destroyed by the electron beam, contact with 
> the air water interface, or both, after vitrification. Has anyone seen 
> something like this before or does anyone have alternative 
> interpretations?
>
> Glow-discharged lacey carbon grids plunge frozen with a Mark IV 
> Vitrobot, clipped and imaged on a Glacios.
>
> Thanks,
>
> James
>
>
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> 3dem at ncmir.ucsd.edu
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