[3dem] How to make grids positively charged during or after glow discharge.

[White, Tommi A.]

Hi Bradford.
We apply a negative glow discharge (Pelco Easiglow with air) to the carbon film of the grid, then immediately add 5 uL of 5 mM Magnesium Acetate solution.  This works for samples that won't stick to a negatively charged film (liposomes) and works well for us.  The reference we have is out of someone's dissertation (thanks John Lemon!) who cites this reference
94. Dubochet, J.; Groom, M.; Mueller-Neuteboom, S., The Mounting of Macromolecules for Electron Microscopy with Particular Reference to Surface Phenomena and the Treatment of Support Films by Glow Discharge. 1982.

Good luck,
Tommi
Tommi A. White, Ph.D.
Assistant Professor of Biochemistry
Director, Electron Microscopy Core Facility
University of Missouri
W117 Veterinary Medicine Building
1600 East Rollins Street
Columbia, MO 65211
573-882-8304
WhiteTo at missouri.edu<mailto:WhiteTo at missouri.edu>
http://emc.missouri.edu<http://emc.missouri.edu/>
@MizzouEMC



From: 3dem <3dem-bounces at ncmir.ucsd.edu> On Behalf Of Ross, Bradford
Sent: Wednesday, July 03, 2019 1:06 PM
To: 3dem at ncmir.ucsd.edu
Subject: [3dem] How to make grids positively charged during or after glow discharge.


Hello Everyone,



I'm currently trying to image some lipid nanoparticles which have a positive charge on their outer surface. Of course, since normal glow discharge treatment typically yields a negative charge on the grids, the particles are all sticking to the lacey carbon support instead of remaining suspended in the vitreous ice layer.



I have heard that Magnesium Acetate can be used to switch the charge from negative to positive after glow discharging, but can't seem to find any protocols for exactly how to treat the grids with it.



Does anyone have a protocol for the use of Magnesium Acetate, or any other suggestions on how to flip the surface charge of the grids to positive? Or other creative solutions I'm not thinking of?



Cheers,
Bradford Ross

Electron Microscopy Technician
BioImaging Facility
University of British Columbia
Cunningham Building Rm. 64
2146 East Mall
Vancouver, B.C.
V6T 1Z4

phone 604-822-6996
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