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What depth penetration can one typically get with atomic force microscopes? (i.e. how far into the tissue can one image?). I have found numbers on acquisition times (minutes) and spatial resolutions (~nm), but what about depth?

Also, what is the sensitivity of AFM? (e.g. in moles)

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    $\begingroup$ I was under the impression that AFM works superficially on specimens. $\endgroup$ – user560 Jan 3 '13 at 1:20
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Taken right from the Wiki page you linked to:

AFM only images the surface of a specimen, to a maximum depth of 10-20 µm and a maximum scan area of 150 µm x 150 µm. Compared with scanning electron microscopy, SEM has a much larger depth of penetration and scanning area (~1 order of magnitude greater). AFM is also a much slower scanning method.

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  • $\begingroup$ AFM does not penetrate into the sample. It CAN give true topographic data from a sample however, with quantifiable heights (SEM cannot really do so). It also has the advantage of being usable in atmosphere or in liquid - on non-conductive samples (which are hard for SEM). High speed AFM can even record videos of proteins doing their thing, and probe the mechanics as well as topography of a cell's lipid membrane. But it has no depth as such. $\endgroup$ – The V Nov 12 '18 at 10:15
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AFM is a surface technique, it has no depth. Spatial resolution can be far in excess of nm - there are publications wherein bonds -ewven hydrogen bonds- are shown. Here is a popularized article which is not behind a paywall https://www.chemistryworld.com/news/new-afm-tip-reopens-hydrogen-bond-imaging-debate/3008878.article

The sensitivity of AFM would not be measured in moles at all. How to measure it depends entirely on the mode you work with. Are you imaging the surface topography? Are you measuring the friction between the tip and the sample? Are you measuring magnetic domains? Surface hardness?

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