[3dem] Alkylamine vapor while glow discharge

[Christopher Kennaway]

I and others in our lab regularly use amylamine treatment, rather than 
alkylamine, although they might well have similar properties. 
Alkylamines are more toxic, however.

Glow discharge in the presence of amylamine causes plasma 
polymerisationin the chamber, depositing a thin layer of polyamines onto 
the carbon surface. This coating is hydrophilic (due to lots of amine 
groups), and improves the wetting of the grid. I suspect that it will 
have variable effects depending on the protein, but for my sample it 
gives thin ice with plenty of protein in the holes.

Our method uses 100 ul amylamine put onto filter paper in a side chamber 
which is slowly opened to the main vacuum chamber after 10 mins of 
pumping by a standard rotary pump. After a further 5 mins, a voltage is 
applied for ~45 seconds.

Hope this helps,

Chris Kennaway

Astbury Centre for Structural Biology
University of Leeds
Leeds, U.K.
c.kennaway at leeds.ac.uk




Eduardo Sanz Garcia wrote:
> The use of alkylamine vapors in glow discharge apparatus makes the
> grid positively charged. But I found some contradictory information
> about the hydrophobicity:
> Some say that it makes the surface hydrophilic, others hydrophobic.
> If it makes the surface hydrophobic, while is still used in cryoEM?
> Shouldn't that prevent the fluid from spreading evenly on the grid
> surface?
> Does someone have experience in this type of treatment?
>
> Additionally,
> Has someone use magnesium acetate, lysine or polylysine after glow
> discharge to make the surface positively charged?
>
> Thank you.
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