Abstract
We present theory and experiments for the force-distance curve of an atomic force microscope (AFM) tip (radius ) indenting a supported fluid bilayer (thickness ). For realistic conditions the force is dominated by the area compressibility modulus of the bilayer and, to an excellent approximation, given by . The experimental AFM force curves from coexisting liquid ordered and liquid disordered domains in three-component lipid bilayers are well described by our model, which provides in agreement with literature values. The liquid ordered phase has a yieldlike response that we model as due to the breaking of hydrogen bonds.
- Received 21 September 2009
DOI:https://doi.org/10.1103/PhysRevE.82.041920
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