Nano-scale mechanical probing of supported lipid bilayers with atomic force microscopy

Chinmay Das; Khizar H. Sheik; Peter D. Olmsted; Simon D. Connell

doi:10.1103/physreve.82.041920

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arXiv · 1006.3937

Nano-scale mechanical probing of supported lipid bilayers with atomic force microscopy

Chinmay Das·Khizar H. Sheik·Peter D. Olmsted·Simon D. Connell

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Abstract

We present theory and experiments for the force-distance curve $F(z_0)$ of an atomic force microscope (AFM) tip (radius $R$) indenting a supported fluid bilayer (thickness $2d$). For realistic conditions the force is dominated by the area compressibility modulus $\kappa_A$ of the bilayer, and, to an excellent approximation, given by $F= \pi \kappa_A R z_0^2/(2d-z_0)^2$. The experimental AFM force curves from coexisting liquid ordered and liquid disordered domains in 3-component lipid bilayers are well-described by our model, and provides $\kappa_A$ in agreement with literature values. The liquid ordered phase has a yield like response that we model by hydrogen bond breaking.

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Chinmay Das, Khizar H. Sheik, Peter D. Olmsted, Simon D. Connell. 2010-06-20. Nano-scale mechanical probing of supported lipid bilayers with atomic force microscopy. https://doi.org/10.1103/physreve.82.041920

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