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Low-Loss EELS Spectral Fingerprints of Lipids and Protein

Published online by Cambridge University Press:  02 July 2020

A. Aitouchen
Affiliation:
Stevens Institute of Technology , Hoboken, NJ07030
S. Shi
Affiliation:
Unilever Research , Edgewater, NJ07020
M. Libera
Affiliation:
Stevens Institute of Technology , Hoboken, NJ07030
M. Misra
Affiliation:
Unilever Research , Edgewater, NJ07020
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Extract

Because of their amphiphilic nature, lipids tend to self-assemble into membranes and other topologically complex structures that can serve a number of functions in both natural and synthetic environments. The structure of lipid assemblies often varies on length scales of 2-100 nm, and morphological studies of such structures often require electron-optical methods. Image contrast in an electron microscope is usually generated by large defocus for unstained samples or by positive/negative staining methodologies. We currently are developing alternate approaches to generate image contrast based on spatially resolved Electron Energy Loss Spectroscopy (EELS) [1]. This has allowed us to distinguish between different lipid species as well as between lipids and protein. Low-loss spectra taken from cholesterol, ceramide and protein (BSA) show that these materials have characteristic spectroscopic fingerprints due to both π and σ valence-electron excitations that are sufficiently different to distinguish between them.

Type
Biological Microanalysis
Copyright
Copyright © Microscopy Society of America

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References

References:

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