Hello Everyone,
I have synthesized some nanomicelles and using one of the particle size counterI come to know that these particles have average size of 5-6 nm ( But also haves some nanoparticles with size 10-30 nm). I have repeated this experiment several times and I got the same results. When I did the TEM I was able to see only particles with only 20-30 nm. I dont know what wrong is going on, I checked the hole size of grid 150 which I used for TEM, its 100 um. Can this possible that the particles are not staying on the grid ?? Can anyone please suggest me the grid for these very small nanoparticle.
Thanks,
Sachin
Dear colleagues, it is necessary to distinguish the soft particles with low electron density (micelles, proteins, virions, etc.) and metal particles with high density (gold, etc). Of course, it is possible to visualize 5 nm gold particles on a formvar support film. But if you have particles from soft material as lipids, it is physically impossible to take normal pictures without special staining. Electron density of these particles are commensurate with Formvar, but the diameter is more less than film's thickness.
Best regards.
You tried to see something very small over rather thick carbon, as a result there might be simply no contrast to see it. The best would be to use some ultrathin support, for example lacy carbon with graphene film grid.
The mesh of TEM-grids doesn't matter in this case. As Dr. Lopatin said, the thickness of support film is the most important factor for such small objects. What kind of film do you use?
For very small (less than 10 nm) objects it is necessary to have ultrathin carbon support film. Formvar film is unsuitable.
Which counter and techniques did you use for estimation of particle size?
How did you prepare the grids? Try to use negative staining technique.
Good luck!
Thank you guys, Can you please suggest me any supplier or catlog number of a product.
Prof. Mayer has described a good protocol here:
https://www.researchgate.net/post/Whats_the_appropriate_concentration_for_a_600kD_protein_complex_in_negative_staining_TEM
It is not simple, but this way is suitable for examination of the small particles.
Good luck!
Hello,
I think the best way is using formvar grid,i used it to do an elemental analysis with the EDX method when i did immunogold where i used colloid gold particles.
I've never had a problem seeing 5nm gold particles on formvar. Make sure the mag is high enough.
Dear colleagues, it is necessary to distinguish the soft particles with low electron density (micelles, proteins, virions, etc.) and metal particles with high density (gold, etc). Of course, it is possible to visualize 5 nm gold particles on a formvar support film. But if you have particles from soft material as lipids, it is physically impossible to take normal pictures without special staining. Electron density of these particles are commensurate with Formvar, but the diameter is more less than film's thickness.
Best regards.
It is necessary to have ultrathin carbon support film, to my knowledge.
http://www.tianld.com/product/277335811
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