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Origins of phase contrast in the atomic force microscope in liquids
- Source :
- Proceedings of the National Academy of Sciences of the United States. August 18, 2009, Vol. 106 Issue 33, p13655, 6 p.
- Publication Year :
- 2009
-
Abstract
- We study the physical origins of phase contrast in dynamic atomic force microscopy (dAFM) in liquids where low-stiffness microcantilever probes are often used for nanoscale imaging of soft biological samples with gentle forces. Under these conditions, we show that the phase contrast derives primarily from a unique energy flow channel that opens up in liquids due to the momentary excitation of higher eigenmodes. Contrary to the common assumption, phase-contrast images in liquids using soft microcantilevers are often maps of short-range conservative interactions, such as local elastic response, rather than tip-sample dissipation. The theory is used to demonstrate variations in local elasticity of purple membrane and bacteriophage [phi]29 virions in buffer solutions using the phase-contrast images. atomic force microscopy | liquid environments | energy dissipation | higher eigenmodes | momentary excitation
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 106
- Issue :
- 33
- Database :
- Gale General OneFile
- Journal :
- Proceedings of the National Academy of Sciences of the United States
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.208129638