Origins of phase contrast in the atomic force microscope in liquids.
Proc Natl Acad Sci U S A
; 106(33): 13655-60, 2009 Aug 18.
Article
in En
| MEDLINE
| ID: mdl-19666560
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 29 virions in buffer solutions using the phase-contrast images.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Microscopy, Phase-Contrast
/
Microscopy, Atomic Force
Type of study:
Risk_factors_studies
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2009
Type:
Article
Affiliation country:
United States