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According to this article from October 2009, http://news.mit.edu/2009/electron-microscope

"Electron microscopes are the most powerful type of microscope, capable of distinguishing even individual atoms. However, these microscopes cannot be used to image living cells because the electrons destroy the samples."

"Now, MIT assistant professor Mehmet Fatih Yanik and his student, William Putnam, propose a new scheme that can overcome this limitation by using a quantum mechanical measurement technique that allows electrons to sense objects remotely. Damage would be avoided because the electrons would never actually hit the imaged objects."

Is it possible yet to image living cells with an electron microscope? If not, has there been any advance in this direction?

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As far as I can see, this remains only a proposal, though it isn't quite my field, so it's possible someone has presented results at a conference somewhere.

Taking a look at the citations of the original paper [Noninvasive electron microscopy with interaction-free quantum measurements, Putnam and Yanik Phys. Rev. A 80, 040902(R)], there don't seem to be any experimental implementations: https://scholar.google.com/scholar?cites=17617747827527972037

From the news story you linked: "[Yanik] expects the work will launch experimental efforts that could lead to a prototype within the next five years." A good reminder about making time estimates!

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  • $\begingroup$ what is your field/occupation? Just curious to know if it's the answer of a microbiologist , a physicist or what $\endgroup$ – Pablo May 3 '17 at 1:54
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    $\begingroup$ I'm a physicist who works in biology, so if this became big, I'd probably have heard about it. (But I'm not an imaging specialist or an EM person - that's my caveat!) $\endgroup$ – AJK May 3 '17 at 2:03
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    $\begingroup$ Not sure! I think it is possible to scan some depth (100s of nm?) with traditional EM, depending on energy, but less than the size of a typical eukaryotic cell. Because of this, there are methods for "slicing" cells to look at the interior, or milling away parts of the surface. Obviously this is pretty destructive, too! $\endgroup$ – AJK May 3 '17 at 3:17
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    $\begingroup$ @Pablo In my opinion, if something like this became feasible to the point that researchers of biology (rather than EM physics) were able to use the technique, it would very quickly become known to just about everyone in biology because it would be such an important step. These groups got a grant to try it out because it would be a big deal and because they came up with a plausible mathematical approach - from the recent citations linked by AJK it seems like they are still working on the physics, and still far from the biology. $\endgroup$ – Bryan Krause May 3 '17 at 22:22
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    $\begingroup$ @Pablo The thought reading experiments are very different from this, completely unrelated, and a bit overstated. They are based on fMRI or EEG and are dependant on a substantial training sequence to teach a model about patterns of brain activity observed in a single subject in a limited number of situations. $\endgroup$ – Bryan Krause May 4 '17 at 1:30
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While it may not be possible yet to image live cells with EM, it is possible to image live animals. For one example, Ishigaki et al. (2012) imaged live ticks (Haemaphysalis flava) with scanning electron microscopy. They could even see the ticks moving their legs inside the microscope for about 1 min after they went in the chamber. The ticks were still alive after they were removed from the vacuum inside the microscope. Half of those exposed to the vacuum and the electron beam died within the next two days, but the rest remained alive for at least two more weeks. Apparently, ticks that were only put inside the vacuum all survived just fine. It was only when they were blasted with the high-energy electron beam that their chances of dying increased.

Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure Live ticks in SEM
Notice that the scale bars in panels B-F should be in $\mu m$, not $mm$

This is not the first study to succeed in imaging live organisms with electron microscopy; that was Pease et al. in 1966. It appears that in some insects the ionizing beam induces the polymerization of "extracellular substances" into a thin (~5 $\mu$m) membrane that acts as a protective "nano-suit" (Takaku et al. 2013). Takaku et al. (2013) could induce the formation of a similarly protective thin membrane by using polysorbate 20, a broadly used surfactant. Artificially inducing the formation of similar "nano-suits" may be a more promising way to image live cells with electron microscopy rather than relying on quantum mechanical measurements. Takaku et al. (2013) even go as far as to speculate that the natural formation of similar "nano-suits" may have acted as a protective shield for prokaryotic extremophiles that could have invaded the earth during early evolution (panspermia hypothesis).


References

- Ishigaki Y, Nakamura Y, Oikawa Y, Yano Y, Kuwabata S, Nakagawa H, et al. (2012). Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure. PLoS ONE 7(3): e32676. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0032676
- Pease, R.F.W., Hayes, T.L., Camp, A.S. and Amer, N.M., (1966). Electron microscopy of living insects. Science, 154(3753): 1185-1186. http://science.sciencemag.org/content/154/3753/1185
- Takaku Y., Suzuki H., Ohta I., IshiiD., Muranaka Y., Shimomura M., and HariyamaT. (2013). A thin polymer membrane, nano-suit, enhancing survival across the continuum between air and high vacuum PNAS 110 (19): 7631-7635. 10.1073/pnas.1221341110

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  • $\begingroup$ I'd love to see how well waterbears survived. $\endgroup$ – Daniel Goldman Dec 9 '17 at 0:19
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    $\begingroup$ @Daniel Given that tardigrades are able to survive orbiting in space, as you are probably aware of since you brought them up, I am confident that they can do at least as well inside the EM column. $\endgroup$ – vkehayas Dec 9 '17 at 12:51
  • $\begingroup$ Indeed. Anyone got a spare electron microscope and some tardigrades? And why on Earth hasn't this experiment been done already? Quick! Let's publish! $\endgroup$ – Daniel Goldman Dec 9 '17 at 12:52

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