I would like to make TEM images of magnetite nanoparticles but I am disoriented with the great ammount of different grids that are avaliable in the market.
try to use SiN (silicon nitrade) or amorphous carbon membranes. They are used for xrays but I think they should work for TEM, the kinetic energy of the electrons is very high. The membranes are amorphous and their scattering should not interfere with the signal coming from the nanoparticles if the composition of the nanoparticles has a larger density of electrons. Let me know if the membranes works because I heve been thinking on them for a long time but I did not have the time to test them yet.
The answer is not simple as many parameters have to be considered. Unfortunately, artefacts are expected from deposition and drying conditions. The effect of physical and chemical nature of the TEM grid will vary will the chemistry and the size of the nanoparticles and the nature/composition of the liquid used to prepare the nanoparticle suspension.
Use carbon coated copper grid and only a drop of very dilute suspension and dried it at room temperature for 24 hrs, It works well. The difficulty with magnetic nanoparticles is that magnetic filed may interefere with EM.
Thank you all por your answers. You've been quite helpfull. Finnally I bought carbon coated copper grid (mesh 200) because the salesperson claimed it will be good enough.
Anyway, can you suggest me some bibliography about TEM preparation?
Also, after you disperse ur particles well just take one or 2 droplet of ur solution on the TEM grid and let them dry for 1 day to be sure there is no movement of the particles when you measure
I'm trying to figure this out too. A technician working with a Titan high res TEM suggested sandwiching the grid between two SiN windows or Formvar coating over the particles on the grid. The main concern is that in high res (200--300KeV) scopes you run the risk of the strong magnetic field pulling your particles off the grid, so they need to be secured for the sake of the instrument. In low res (10Kev) instruments, where the mag field is weaker, this is apparently not as big of a concern.
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