[3dem] Freezing hydrophobic grid

[Shi, Dan (NIH/NCI) [C]]

Another way I learned to make hydrophobic carbon surface in Dr. Stokes
lab was to glow-discharge the grids with few ul of amylamine (the method
might be developed in 80s by Dr. Dubochet I don't remember exactly). But
I used this for holey carbon film and blotted from the back of the grids
to get thin ice evenly cover the carbon area. Good Luck,

 

Dan Shi

 

 

________________________________

From: Bill Tivol [mailto:tivol at caltech.edu] 
Sent: Wednesday, April 30, 2008 4:33 PM
To: 3dem at ucsd.edu
Subject: Re: [3dem] Freezing hydrophobic grid

 

 

On Apr 7, 2008, at 8:10 PM, Puey Ounjai wrote:





I am trying to make thin ice on hydrophobic carbon surface (continuous).
I am trying to make ice equally spreaded on the surface. 

Usually, it breaks and form droplet on the carbon? 

Any  suggestion would be highly appreciated!

 

Dear Puey,

            This problem was faced and solved for cryoEM by
glow-discharging the carbon to make the surface hydrophyllic.  One or
two minutes treatment with a rather low power plasma cleaner, such as
the Harrick instrument will do it.  If you need the surface of the
carbon to remain hydrophobic, then you will have to add something to the
water, such as a detergent or surfactant in order to get uniform wetting
of the surface.  You could also freeze small droplets of water by using
an atomizer to deposit them onto a cold metal surface, then removing the
now frozen droplets and applying them to the grid, which must be done
without allowing the droplets to melt, of course.

Yours,

Bill Tivol, PhD

EM Scientist

Electron Cryo-Microscopy Facility

Broad Center, Mail Code 114-96

California Institute of Technology

Pasadena CA 91125

(626) 395-8833

tivol at caltech.edu

 

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