Nanoscale mechanical probing of supported lipid bilayers with atomic force microscopy
Nanoscale mechanical probing of supported lipid bilayers with atomic force microscopy
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DOI：
10.1103/physreve.82.041920
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发表时间：
2010-10-25
影响因子：
2.4
通讯作者：
Connell, Simon D.
中科院分区：
文献类型：
--
作者：
Das, Chinmay;Sheikh, Khizar H.;Connell, Simon D.
给出了原子力显微镜(AFM)针尖(半径R)压入支撑流体双层(厚度2d)的力-距离曲线F(z(0))的理论和实验结果。对于实际情况，力由双层的面积可压缩系数kappa(A)控制，并且非常接近地给出F=pi kappa(A)Rz(0)(2)/(2d-z(0))(2)。我们的模型很好地描述了三组分脂双层中共存的液体有序和液体无序磁区的AFM力曲线，提供了与文献值一致的kappa(A)。液体有序相具有类似屈服的响应，我们将其模拟为由于氢键的断裂。
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)Rz(0)(2)/(2d-z(0))(2) . 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 kappa(A) in agreement with literature values. The liquid ordered phase has a yieldlike response that we model as due to the breaking of hydrogen bonds.