Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications

García, Ricardo García

doi:10.1039/d0cs00318b

Cited by 305 publications

(330 citation statements)

References 352 publications

(568 reference statements)

Supporting

Mentioning

311

Contrasting

Unclassified

Order By: Relevance

“…Simple geometrical considerations led to the conclusion that such a change in tilt angle would result in ~0.6 nm thinning of the membrane. According to AFM data, the membrane thinning was found to be ~1.0 nm; however, it should be noted that tip-sample interaction during AFM imaging results in elastic deformation of the soft film [ 33 ]. Consequently, the bilayer is slightly compressed under the tip load, which in turn gives underestimated values of the thickness.…”

Section: Resultsmentioning

confidence: 99%

Interactions of Linear Analogues of Battacin with Negatively Charged Lipid Membranes

et al. 2021

View full text Add to dashboard Cite

The increasing resistance of bacteria to available antibiotics has stimulated the search for new antimicrobial compounds with less specific mechanisms of action. These include the ability to disrupt the structure of the cell membrane, which in turn leads to its damage. In this context, amphiphilic lipopeptides belong to the class of the compounds which may fulfill this requirement. In this paper, we describe two linear analogues of battacin with modified acyl chains to tune the balance between the hydrophilic and hydrophobic portion of lipopeptides. We demonstrate that both compounds display antimicrobial activity with the lowest values of minimum inhibitory concentrations found for Gram-positive pathogens. Therefore, their mechanism of action was evaluated on a molecular level using model lipid films mimicking the membrane of Gram-positive bacteria. The surface pressure measurements revealed that both lipopeptides show ability to bind and incorporate into the lipid monolayers, resulting in decreased ordering of lipids and membrane fluidization. Atomic force microscopy (AFM) imaging demonstrated that the exposure of the model bilayers to lipopeptides leads to a transition from the ordered gel phase to disordered liquid crystalline phase. This observation was confirmed by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) results, which revealed that lipopeptide action causes a substantial increase in the average tilt angle of lipid acyl chains with respect to the surface normal to compensate for lipopeptide insertion into the membrane. Moreover, the peptide moieties in both molecules do not adopt any well-defined secondary structure upon binding with the lipid membrane. It was also observed that a small difference in the structure of a lipophilic chain, altering the balance between hydrophobic and hydrophilic portion of the molecules, results in different insertion depth of the active compounds.

show abstract

Section: Resultsmentioning

confidence: 99%

Interactions of Linear Analogues of Battacin with Negatively Charged Lipid Membranes

et al. 2021

View full text Add to dashboard Cite

show abstract

“…On the other hand, AFM has demonstrated its superiority over SICM in terms of imaging resolution 38 . AFM is also more versatile in terms of retrieving information about the nanomechanical sample properties 39 and can even be used for molecular-specific imaging 40 . Due to the fragile nature of the glass nanocapillary, SICM is less forgiving of imaging mistakes that can lead to fracture of the capillary.…”

Section: Discussionmentioning

confidence: 99%

Correlative 3D microscopy of single cells using super-resolution and scanning ion-conductance microscopy

Navikas

Leitão

Grußmayer

et al. 2020

Preprint

View full text Add to dashboard Cite

High-resolution live-cell imaging is necessary to study complex biological phenomena. Modern fluorescence microscopy methods are increasingly combined with complementary, label-free techniques to put the fluorescence information into the cellular context. The most common high-resolution imaging approaches used in combination with fluorescence imaging are electron microscopy and atomic-force microscopy (AFM), originally developed for solid-state material characterization. AFM routinely resolves atomic steps, however on soft biological samples, the forces between the tip and the sample deform the fragile membrane, thereby distorting the otherwise high axial resolution of the technique. Here we present scanning ion-conductance microscopy (SICM) as an alternative approach for topographical imaging of soft biological samples, preserving high axial resolution on cells. SICM is complemented with live-cell compatible super-resolution optical fluctuation imaging (SOFI). To demonstrate the capabilities of our method we show correlative 3D cellular maps with SOFI implementation in both 2D and 3D with self-blinking dyes for two-color high-order SOFI imaging. Finally, we employ correlative SICM/SOFI microscopy for visualizing actin dynamics in live COS-7 cells with subdiffractional resolution.

show abstract

“…2-7 to interpret F vs. d and extract Young's modulus E by fitting the AFM experimental data. Several reviews are focused on the selection of correct contact mechanics model (interested readers can retrieve extensive information in [17,36,37]), here we want to focus on the operational routine to extract Young's Modulus, addressing its justification and pointing the direction to alternative models if needed.…”

Section: Contact Mechanics Modelmentioning

confidence: 99%

“…An AFM consists of a probe supported by an elastic cantilever that applies a vertical force at a defined speed on target sample while detecting the reaction force with pN level sensitivity. Mathematical models of contact mechanics between the AFM probe and the cell are required to interpret and quantify data derived from AFM indentation on living cells [16,17]. Indentation at low speed (frequency of events ≈ 1 Hz) is considered quasi-static and providing a wealth of information such as surface positioning, reaction force and probe-surface bonding force, in turn, converted in morphology, Young's modulus map and adhesion map.…”

Section: Introductionmentioning

confidence: 99%

Cells nanomechanics by atomic force microscopy: focus on interactions at nanoscale

Zhou

Zhang²,

Tang

et al. 2021

Advances in Physics: X

View full text Add to dashboard Cite

Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications

Abstract: This review provides an introduction to the state-of-the-art force microscope methods to map at high-spatial resolution the elastic and viscoelastic properties of proteins, polymers and cells.

Cited by 305 publications

References 352 publications

Interactions of Linear Analogues of Battacin with Negatively Charged Lipid Membranes

Interactions of Linear Analogues of Battacin with Negatively Charged Lipid Membranes

Correlative 3D microscopy of single cells using super-resolution and scanning ion-conductance microscopy

Cells nanomechanics by atomic force microscopy: focus on interactions at nanoscale

Contact Info

Product

Resources

About