Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an ‘aloof’ electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies <1 eV can be ‘safely’ investigated. To demonstrate the potential of aloof spectroscopy, we record electron energy loss spectra from biogenic guanine crystals in their native state, resolving their characteristic C–H, N–H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ∼10 nm, simultaneously combined with imaging in the electron microscope.
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- Damage-Free Vibrational Spectroscopy of Biological Materials in the Electron Microscope
- Rez, Peter (Author)
- Aoki, Toshihiro (Author)
- March, Katia (Author)
- Gur, Dvir (Author)
- Krivanek, Ondrej L. (Author)
- Dellby, Niklas (Author)
- Lovejoy, Tracy C. (Author)
- Wolf, Sharon G. (Author)
- Cohen, Hagai (Author)
- College of Liberal Arts and Sciences (Contributor)
- Digital object identifier: 10.1038/ncomms10945
- Identifier TypeInternational standard serial numberIdentifier Value2041-1723
- The final version of this article, as published in Nature Communications, can be viewed online at: https://www.nature.com/articles/ncomms10945
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Rez, P., Aoki, T., March, K., Gur, D., Krivanek, O. L., Dellby, N., . . . Cohen, H. (2016). Damage-free vibrational spectroscopy of biological materials in the electron microscope. Nature Communications, 7, 10945. doi:10.1038/ncomms10945