We have a new AFM with a capability to achive high resolution images (up to 50nm). The AFM tips can scan the surface of the object and as well, can penetrate into the object. We also have the capability to use the tip for scanning planktonic bacterial cells inside a medium.
Not my particular field, but is this helpful:
Article Immobilisation of living bacteria for AFM imaging under phys...
@Ofir Menashe
Why not use optical microscope with multiple accessories that is widely used in cells imaging. It is much easier than AFM.
Agree. I do use an optical images.
I just think of the potential of looking behind by employing higher resolution and different growth states.
Thank you, Xuhua.
Dear Ofir,
Hope that you get what you would like to do with the AFM.
In air it could be likely that you do not need anything special to have the bacteria fixed to the surface strong enough to make the measurement (physical absortpion).
However in liquid it could be rather different as they may be easily detached from the surface.
Once you get that you need to realize that AFM measures mainly what is on the surface ,not inside. As you mention, you can also apply some pressure at the same time, which may help you to detect the presence of inner organelles, but it could be difficult to identify them just by the form or geometry in that manner. And if the membrane brakes or collapses, then it creates a big mess difficult to handle with the AFM tip.
I attach an image of some examples so that you can have an idea with an AFM with more resolution than the one you mention you have. You can even see a bacteria in an early stage of cell-division
But certainly you can study different growth states with better details than optical microscope.
Hope that you are lucky and feel free to contact me for further discussion
Dear Nicolas,
thank you so much for your input and photos. It is really helping. I had already fixed a bacterial culture on the surface of a cover glass by heat. still, I do not have a sufficient images. I hope that during next week, I will have some dissent images.
Keep safe, Ofir
Dear Ofir,
I hope my answer is not too late for you, I have attached the images of E. coli imaging by AFM from my previous work of the ten years ago during my master thesis.
For sample preparation, first surface was treated by ECM as a thin layer as possible then dry in a clean area for at least one hour. I recommended you to use spin coating technique for coating. Then the cell specimen should be cleaned, for instant, vortex and centrifugation for several times and resuspended as diluted dispersion before dropped and dried on the treated substrates.
AFM operation under liquid ambient requires careful and delicate handle, you should consider for the tip feature, mode of operation, the force exertion and so on. For me I preferred to used the soft tip from Veeco and Olympus (use in liquid only) with slow rate scan (0.5 line or lower). Be aware that during approaching, the tip reach to the real surface (you can used several technique to avoid meniscus effect at the tip). Do not forget to optimize the I and P gain to get the best signal.
Hope this is helpful for you and feel free for further discussion
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