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Electron microscopy has drawbacks when it comes to studying biological samples. The sample has to be prepared for examination in a vacuum chamber using ionizing
by cstross 5y ago
Electron microscopy has drawbacks when it comes to studying biological samples. The sample has to be prepared for examination in a vacuum chamber using ionizing radiation and using fixating processes and reagents that kill the cells and may damage/distort lipid membranes. Brief intro here:
https://www.sciencelearn.org.nz/resources/500-preparing-samples-for-the-electron-microscope https://www.sciencelearn.org.nz/resources/500-preparing-samp...
A low energy optical microscope can examine living samples (in aqueous environments).
- amelius 5y agoBut an electron microscope can see small molecules or even atoms.
- cstross 5y agoThe structures in biological samples are often very delicate, their structures ruined by all of those treatments: think soap bubbles rather than bones. It doesn't matter how small the structures you can observe are if you can't be sure they haven't been warped and distorted by dehydration, doping with heavy metals like osmium, exposure to vacuum, and being blasted with radiation until it's heated to 150 degrees celsius. Don't get me wrong: electron microscopy is great for mineral samples, and can be used for biological samples subject to some constraints. But you can't examine specimens with it while they're alive.