Recent progress in AFM molecular recognition studies

Dufrêne, Yves F.; Hinterdorfer, Peter

doi:10.1007/s00424-007-0413-1

Cited by 97 publications

(75 citation statements)

References 45 publications

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“…With the manufacture of functionalized AFM tips that can physically interact with the cell membrane in the nanoscale range, it has become possible to recognize specific sites on artificial surfaces and cells [5,18]. Applying this technique, VE-cadherin-binding sites on fixed endothelial cells could be identified at a lateral resolution close to 5 nm [4].…”

Section: Discussionmentioning

confidence: 99%

Aldosterone receptor sites on plasma membrane of human vascular endothelium detected by a mechanical nanosensor

Wildling

Hinterdorfer

Kusche-Vihrog

et al. 2008

Pflugers Arch - Eur J Physiol

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The mineralocorticoid hormone aldosterone acts on target cells of kidney, colon, and the cardiovascular system through genomic and nongenomic pathways. Although the classical intracellular mineralocorticoid receptor plays a key role in mediating both pathways, it is unclear whether there are specific aldosterone receptors located on the cell surface. To search for such sites in vascular endothelium, we used an atomic force microscope (AFM) which measures unbinding forces based on single molecular recognition between an aldosterone-loaded AFM tip and the cell membrane. Aldosterone was tethered covalently via linker molecules to an AFM tip. Human endothelial cells (EA.hy926) were grown in culture and studied in buffer at 37 degrees C. Using the aldosterone-functionalized AFM tip as a mechanical nanoscale indenter, unbinding forces could be measured at randomly chosen sites of the plasma membrane. Sites with strong interactions between AFM tip and cell surface could be identified exhibiting unbinding forces of about 65 pN. The binding probability between the aldosterone-loaded tip and the cell surface at selected membrane sites was 53 +/- 7.2%. Addition of an excess supply of aldosterone to the bath solution blocked the binding of the aldosterone-loaded tip to the cell surface. The binding probability was reduced to 8.0 +/- 1.8% when an excess supply of aldosterone was added to the bath. However, it was not influenced by the addition of spironolactone or dexamethasone. We conclude that aldosterone receptor sites exist on the cell surface of vascular endothelial cells distinct from the classical mineralocorticoid receptors and insensitive to glucocorticoids. Binding of aldosterone to these receptors initiates an intracellular signaling cascade that precedes the classical genomic response and most likely participates in the control of vascular resistance.

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Section: Discussionmentioning

confidence: 99%

Aldosterone receptor sites on plasma membrane of human vascular endothelium detected by a mechanical nanosensor

Wildling

Hinterdorfer

Kusche-Vihrog

et al. 2008

Pflugers Arch - Eur J Physiol

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“…The atomic force microscope (AFM) enables the detection of very small forces and therefore enables quantification of the interaction between a probe and a sample [14,27]. An AFM equipped with either a sharp tip or a colloidal probe in which the tip is replaced by a sphere [4,13,36] has been widely used to measure the mechanical properties of soft materials.…”

Section: Introductionmentioning

confidence: 99%

Elasticity measurement of living cells with an atomic force microscope: data acquisition and processing

Carl

Schillers

2008

Pflugers Arch - Eur J Physiol

208

176

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Elasticity of living cells is a parameter of increasing importance in cellular physiology, and the atomic force microscope is a suitable instrument to quantitatively measure it. The principle of an elasticity measurement is to physically indent a cell with a probe, to measure the applied force, and to process this force-indentation data using an appropriate model. It is crucial to know what extent the geometry of the indenting probe influences the result. Therefore, we indented living Chinese hamster ovary cells at 37 degrees C with sharp tips and colloidal probes (spherical particle tips) of different sizes and materials. We furthermore developed an implementation of the Hertz model, which simplifies the data processing. Our results show (a) that the size of the colloidal probe does not influence the result over a wide range (radii 0.5-26 microm) and (b) indenting cells with sharp tips results in higher Young's moduli ( approximately 1,300 Pa) than using colloidal probes ( approximately 400 Pa).

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“…We establish the specific nature of measured interactions using the "empty tether" approaches. 15,29,32,40,[51][52][53] In empty tether control experiments, one of a pair of molecules involved in the measured interactions is removed, blocked, or chemically modified. In a control experiment with the AFM probe modified with PEG tethers without biotin, only 12 rupture events out of 6144 force curves (0.2% detection probability) have been identified by our data analysis approach as rupture events.…”

Section: Methodsmentioning

confidence: 99%

Distributions of Parameters and Features of Multiple Bond Ruptures in Force Spectroscopy by Atomic Force Microscopy

Guo

Lad

et al. 2010

J. Phys. Chem. C

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Force spectroscopy measurement of rupture forces of bound molecules becomes an important physicochemical tool in characterizing intermolecular interactions. Atomic force microscopy (AFM) measurements are among the most common approaches in implementation of this technique. Kinetic information about the molecular bond under study is usually extracted assuming that the detected rupture force comes from rupturing of a single bond. However, multiple bond ruptures might occur in experiments. In this article, we consider how the presence of multiple bonds is manifested in the distribution of parameters that are typically extracted in force spectroscopy experiments. Of particular interest here are the distributions of rupture forces and Kuhn lengths of polymeric tethers. We show that multiple bond ruptures might contribute to the measured distributions even when these distributions have a well-defined single peak. Also, we consider how the probability to form multiple bonds depends on probe velocity. The developed analytical models are applied to experimental data of biotin-streptavidin ruptures. The velocity dependence of the amplitude of high force tail supports the hypothesis of multiple bond nature of the measured high forces.

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Recent progress in AFM molecular recognition studies

Cited by 97 publications

References 45 publications

Aldosterone receptor sites on plasma membrane of human vascular endothelium detected by a mechanical nanosensor

Aldosterone receptor sites on plasma membrane of human vascular endothelium detected by a mechanical nanosensor

Elasticity measurement of living cells with an atomic force microscope: data acquisition and processing

Distributions of Parameters and Features of Multiple Bond Ruptures in Force Spectroscopy by Atomic Force Microscopy

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