Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• materials is usually performed through contact-mode methods. Contact-resonance AFM, force-modulation AFM and static force spectroscopy are the most popular examples in this category [9][10][11][12][13]. The permanent-contact nature of these methods offers an important advantage in mechanical

Optimizing qPlus sensor assemblies for simultaneous scanning tunneling and noncontact atomic force microscopy operation based on finite element method analysis

• Omur E. Dagdeviren and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2017, 8, 657–666, doi:10.3762/bjnano.8.70

• -simplification for quantitative force spectroscopy [36], inducing a systematic error in such measurements. We also established that the more k and f0 depart from the values without wire connection, the smaller Δf f0/k tends to be as k usually increases faster than f0 and that asymmetric wire connections may

Dynamic of cold-atom tips in anharmonic potentials

• Tobias Menold,
• Peter Federsel,
• Carola Rogulj,
• Hendrik Hölscher,
• József Fortágh and
• Andreas Günther

Beilstein J. Nanotechnol. 2016, 7, 1543–1555, doi:10.3762/bjnano.7.148

• particle interactions and anharmonic motion have a significant impact on the tip dynamics. Conclusion: Our findings will be crucial for the realization of high-sensitivity force spectroscopy with cold-atom tips and could possibly allow for the development of advanced spectroscopic techniques such as Q

• oscillation amplitude and frequency. Precision force spectroscopy [32] with cold atoms comes thus into direct reach, with expected force sensitivities in the yN-regime [29]. Therefore, the dynamics of cold-atom tips in an anharmonic potential must be fully understood and a method for real-time observation of

• , we introduce a novel method for local density probing, allowing detection of the tip dynamics in real time. The first measurements on oscillating cold-atom tips show very good agreement with theoretical and numerical calculations. Our findings will be essential for future force spectroscopy with cold

Advanced atomic force microscopy techniques III

• Thilo Glatzel and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2016, 7, 1052–1054, doi:10.3762/bjnano.7.98

• -cell force spectroscopy is used by a biophysics group around Jonne Helenius to quantify the contribution of cell adhesion to specific substrates at both the cell and single molecule level [19]. Furthermore, physico-mechanical properties of intestinal cells were elucidated by force curve measurements by

• frequency tangential excitation [25]. On the other hand, force spectroscopy and advanced imaging and analysis techniques form a major part of this Thematic Series. For all AFM experiments the tip condition is one of the most critical parameters, Fei Long et al. presented a method for single-molecule probe

Correlative infrared nanospectroscopic and nanomechanical imaging of block copolymer microdomains

• Benjamin Pollard and
• Markus B. Raschke

Beilstein J. Nanotechnol. 2016, 7, 605–612, doi:10.3762/bjnano.7.53

• , domain structure [8], and degrees of crystallinity. However, information beyond nanoscale IR response is sometimes desired for a more complete understanding of molecular interactions and their relationship to material function. Nanomechanical properties, measured through force spectroscopy, can provide

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34

• biotin-terminated tripodal tips 14, which are useful for chemical force spectroscopy (CFS) measurements of the ligand–protein receptor interaction in a biotin–avidin model system, toward the development of high-throughput drug screening, and studies of transmembrane receptors [107]. Also, Whitesell and

A simple method for the determination of qPlus sensor spring constants

• John Melcher,
• Julian Stirling and
• Gordon A. Shaw

Beilstein J. Nanotechnol. 2015, 6, 1733–1742, doi:10.3762/bjnano.6.177

• technique opens up a broad materials spectrum to the possibility of atomic-scale analysis. This new capability has led to imaging with sub-atomic resolution [1], and chemical identification of surface atoms [2] and molecules [3], as well as dynamic force spectroscopy in a wet chemical environment [4

• % stiffer than and for tip heights greater than 632 μm, the approximation deviates by less than 1%. In the following section, we neglect the error in the approximation, however, the small correction factor can be estimated from the theoretical model if desired. Modeling dynamic force spectroscopy

• (less than 3%) in stiffness by testing at a lateral offset from the beam axis. Finally, we note that for sufficiently long tips, the compliance of the tip contributes to the parasitic tip motion [32][33]. This, in turn, influences the spring constant and force spectroscopy results presented here. To

Atomic force microscopy as analytical tool to study physico-mechanical properties of intestinal cells

• Christa Schimpel,
• Oliver Werzer,
• Eleonore Fröhlich,
• Gerd Leitinger,
• Markus Absenger-Novak,
• Birgit Teubl,
• Andreas Zimmer and
• Eva Roblegg

Beilstein J. Nanotechnol. 2015, 6, 1457–1466, doi:10.3762/bjnano.6.151

• ], micropipette aspiration [16] and magnetic/optical tweezers or optical traps [17][18][19], atomic force microcopy (AFM) is a versatile and potent tool for studying biological structures [20][21][22]. AFM enables both topographical and force curve measurements (atomic force spectroscopy) [23]. The former allow

• detail, atomic force spectroscopy was used. For local force curve (indentation) measurements, the tip of the cantilever was placed over the location of interest (i.e., peripheral region/cell edge, nuclear area, cell body/cytoplasm) and the mechanical response was recorded as the cantilever was moved

• band pass detection for the red channel and images were examined with CLSM (Zeiss LSM 510 META) equipped with equipped with ZEN software (Zeiss Germany). Atomic force spectroscopy and indentation force measurements The mechanical properties of the cells were obtained via force curve measurements, (i.e

Improved atomic force microscopy cantilever performance by partial reflective coating

• Zeno Schumacher,
• Yoichi Miyahara,
• Laure Aeschimann and
• Peter Grütter

Beilstein J. Nanotechnol. 2015, 6, 1450–1456, doi:10.3762/bjnano.6.150

• contact mode and force spectroscopy, a cantilever with minimal low-frequency force noise is desirable. We present a study on cantilevers with a partial reflective coating on the detector side. For this study, soft (≈0.01 N/m) and stiff (≈28 N/m) rectangular cantilevers were used with a custom partial

• Supporting Information File 1, Figure S1 for data). Advantages for static AFM: reduced low-frequency noise For static AFM measurement such as contact mode or force spectroscopy, a low 1/f noise is important. In this section, the cantilever deflection noise density spectra of the soft cantilevers measured

• shown in Figure 2 with the measured spring constant of each cantilever. Here, the difference between fully and partially coated cantilevers becomes even more pronounced due to the higher spring constant of the fully coated cantilever. An additional measure to quantify the noise for force spectroscopy

Probing fibronectin–antibody interactions using AFM force spectroscopy and lateral force microscopy

• Andrzej J. Kulik,
• Małgorzata Lekka,
• Kyumin Lee,
• Grazyna Pyka-Fościak and
• Wieslaw Nowak

Beilstein J. Nanotechnol. 2015, 6, 1164–1175, doi:10.3762/bjnano.6.118

• between the two left and two right quadrants. For an AFM working in force spectroscopy mode (referred to here as AFM-FS), the interactions forces are determined from the analysis of force curves. A force curve represents the dependence between the deflection of the AFM cantilever in the direction

• force spectroscopy or lateral force spectroscopy). This likely indicates some differences in the vertical and lateral unbinding scenarios. The computer modelling of a similar unbinding event in an MCP1-IgG antibody complex showed that lateral unbinding forces are about 30% lower than those

• surface was measured in contact mode over an area of 10 × 10 µm, with set point of 0.2 nN and scan rate of 0.8 Hz. Unbinding experiments In AFM-based classical force spectroscopy, the unbinding forces of the interaction between fibronectin (FN) and monoclonal antibody against FN (FN-Mab) were measured

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• Instrument AG, Berlin, Germany) with HEPES buffered culture medium kept at 37 °C. AFM images were performed in contact mode. Before force spectroscopy measurements the exact spring constant of the used cantilever was determined by thermal noise analysis using software provided by the manufacturer. Local

Increasing throughput of AFM-based single cell adhesion measurements through multisubstrate surfaces

• Miao Yu,
• Nico Strohmeyer,
• Jinghe Wang,
• Daniel J. Müller and
• Jonne Helenius

Beilstein J. Nanotechnol. 2015, 6, 157–166, doi:10.3762/bjnano.6.15

• cells regulate adhesion by expressing and regulating a diverse array of cell adhesion molecules on their cell surfaces. Since different cell types express distinct sets of cell adhesion molecules, substrate-specific adhesion is cell type- and condition-dependent. Single-cell force spectroscopy is used

• matrix proteins, fibronectin, collagen I and laminin 332, was examined. The adhesion of each cell line to different matrix proteins was found to be distinct; no two cell lines adhered equally to each of the proteins. The PDMS masks improved the throughput limitation of single-cell force spectroscopy and

• force spectroscopy; Introduction The regulated adhesion of mammalian cells with the extracellular matrix (ECM) and surrounding cells is crucial in biological processes such as cell migration, differentiation, proliferation, and apoptosis. Since impaired cell adhesion causes a wide range of diseases

Accurate, explicit formulae for higher harmonic force spectroscopy by frequency modulation-AFM

• Kfir Kuchuk and
• Uri Sivan

Beilstein J. Nanotechnol. 2015, 6, 149–156, doi:10.3762/bjnano.6.14

• reconstruct short range forces more accurately than the fundamental harmonic when the oscillation amplitude is small compared with the interaction range. Keywords: atomic force spectroscopy; higher harmonic FM-AFM; Introduction AFM measurements are presently utilized to generate atomic resolution [1][2], 3D

• generated by the nonlinear tip–surface interaction (to be distinguished from higher flexural modes of the cantilever) are related to higher derivatives of the force, and thus carry additional information on the interaction [5][6][7][8][9][10][11]. Broad implementation of force spectroscopy by analysing

• force spectroscopy with no need for multiple-harmonics measurements and analysis. There are several advantages to be gained by expressing the force as a function of higher harmonic amplitudes. First, the existence of these amplitudes depends entirely on the presence of nonlinear interaction forces

Multifunctional layered magnetic composites

• Maria Siglreitmeier,
• Baohu Wu,
• Tina Kollmann,
• Martin Neubauer,
• Gergely Nagy,
• Dietmar Schwahn,
• Vitaliy Pipich,
• Damien Faivre,
• Dirk Zahn,
• Andreas Fery and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2015, 6, 134–148, doi:10.3762/bjnano.6.13

• magnetite [43]. Mechanical characterization To examine the mechanical properties of the composite materials we conducted some preliminary experiments. Force spectroscopy measurements with the colloidal probe technique [46][47] were performed on bare and nanoparticle-loaded gelatin as well as on bare and

• pressure. To account for the manifold of possible arrangements intrinsic to the systems complexity a series of 200 independent docking runs were performed for each ionic species. Mechanical characterization Force spectroscopy experiments were conducted at the atomic force microscope (AFM) Nanowizard® I

High-frequency multimodal atomic force microscopy

• Adrian P. Nievergelt,
• Jonathan D. Adams,
• Pascal D. Odermatt and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2014, 5, 2459–2467, doi:10.3762/bjnano.5.255

• spring constants [10][11][12]. Increasing the cantilever resonance frequency enables faster imaging and force spectroscopy [12][13][14][15][16][17], and small, high-frequency AFM cantilevers have less viscous drag, lowering force noise [18]. Many of the techniques for extracting mechanical information

Modification of a single-molecule AFM probe with highly defined surface functionality

• Fei Long,
• Bin Cao,
• Ashok Khanal,
• Shiyue Fang and
• Reza Shahbazian-Yassar

Beilstein J. Nanotechnol. 2014, 5, 2122–2128, doi:10.3762/bjnano.5.221

• , Michigan, USA 10.3762/bjnano.5.221 Abstract Single-molecule force spectroscopy with an atomic force microscope has been widely used to study inter- and intramolecular interactions. To obtain data consistent with single molecular events, a well-defined method is critical to limit the number of molecules at

• area would result in a highly defined surface functionality of the probe down to single molecule level with high reproducibility. Keywords: atomic force microscopy; click reaction; force spectroscopy; single molecule modification; Introduction Single-molecule force spectroscopy (SMFS) has become one

• resulting larger contact area between probe and surface during force spectroscopy. The value of nav of the specific interaction was 1.1–1.5 for the Si probe, demonstrating a successful single-molecule modification. Similar values of nav were obtained for the other three Si probes with a maximum value of 2.1

Mechanical properties of sol–gel derived SiO₂ nanotubes

• Boris Polyakov,
• Mikk Antsov,
• Sergei Vlassov,
• Leonid M Dorogin,
• Mikk Vahtrus,
• Roberts Zabels,
• Sven Lange and
• Rünno Lõhmus

Beilstein J. Nanotechnol. 2014, 5, 1808–1814, doi:10.3762/bjnano.5.191

• tests. Prior to the three-point bending test an AFM image of a NT suspended over a trench was taken in tapping mode at low magnification (typically 10 × 10 μm, Figure 3a). In order to ensure proper tip positioning during force spectroscopy a NT was scanned sequentially at a higher magnification

Probing viscoelastic surfaces with bimodal tapping-mode atomic force microscopy: Underlying physics and observables for a standard linear solid model

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1649–1663, doi:10.3762/bjnano.5.176

• springs and multiple relaxation times. However, the inversion of the surface parameters from experimental data is an extremely challenging task even with the simple SLS. Further research is encouraged on single-cycle force spectroscopy measurement as well as inversion methodologies specific for

Hydrophobic interaction governs unspecific adhesion of staphylococci: a single cell force spectroscopy study

• Nicolas Thewes,
• Peter Loskill,
• Philipp Jung,
• Henrik Peisker,
• Markus Bischoff,
• Mathias Herrmann and
• Karin Jacobs

Beilstein J. Nanotechnol. 2014, 5, 1501–1512, doi:10.3762/bjnano.5.163

• surface, single cell force spectroscopy is applied: A single cell of the apathogenic species Staphylococcus carnosus isolate TM300 is used as bacterial probe. With the exact same bacterium, hydrophobic and hydrophilic surfaces can be probed and compared. We find that as far as 50 nm from the surface

• hydrophobic (hydrophilic) surfaces. Keywords: atomic force microscopy (AFM); force spectroscopy; hydrophobic interaction; single cell; Staphylococcus carnosus; Introduction Members of the genus Staphylococcus are known to form extremely resistant biofilms, some of which can cause severe infectious diseases

• measuring bacterial adhesion forces has been introduced: single-cell force spectroscopy is a special mode of an atomic force microscope (AFM) [16] and is optimized to investigate adhesion forces [17][18] of single bacterial cells in a very controlled manner: By using AFM-cantilevers functionalized with

Calibration of quartz tuning fork spring constants for non-contact atomic force microscopy: direct mechanical measurements and simulations

• Jens Falter,
• Marvin Stiefermann,
• Gernot Langewisch,
• Philipp Schurig,
• Hendrik Hölscher,
• Harald Fuchs and
• André Schirmeisen

Beilstein J. Nanotechnol. 2014, 5, 507–516, doi:10.3762/bjnano.5.59

• precision. Recent achievements of this force spectroscopy method manifest in the identification of the chemical identity of single atoms in an alloy [2] or the measurement of the force applied during the controlled manipulation of molecules or atoms on a surface [3][4]. nc-AFM experiments at the atomic

• are far from mass production and therefore exhibit a large spread of geometric – and thus of elastic parameters. Especially the precise knowledge of the sensor stiffness kqPlus is crucial for quantitative interpretation of force spectroscopy measurements. Early spectroscopy experiments compared

• result is that even these sensors show a significantly high spread of kqPlus = 1480–1708 N/m, which demonstrates the need to calibrate each individual sensor that is used for quantitative nc-AFM force spectroscopy measurements. FEM simulations Special care was taken to make the geometric model of the

Energy dissipation in multifrequency atomic force microscopy

• Valentina Pukhova,
• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2014, 5, 494–500, doi:10.3762/bjnano.5.57

• cross-correlation (XWT) technique in atomic force spectroscopy to reconstruct complex force dynamics in the tip–sample impact regime, when higher cantilever modes are simultaneously excited [5]. The XWT analysis allows to retrieve the displacement, velocity and acceleration of the tip simultaneously for

The softening of human bladder cancer cells happens at an early stage of the malignancy process

• Jorge R. Ramos,
• Joanna Pabijan,
• Ricardo Garcia and
• Malgorzata Lekka

Beilstein J. Nanotechnol. 2014, 5, 447–457, doi:10.3762/bjnano.5.52

• lines differ in terms of the organization of the cytoskeleton (presence/absence of stress fibers, distinct actin expression level) and the elastic properties measured by force spectroscopy. The cancerous cells are more compliant with respect to the non-malignant cells. Regardless of histological grades

• strongly supports the usefulness of cell deformability in detecting cancer-related changes in bladder cancer. Such a relation has not been observed so far for any other cells measured by AFM in which usually a gradual drop of stiffness was observed. Results Cell morphology Force spectroscopy experiments

• [27]. First, the force curves were converted into force-versus-indentation curves and those curve were fitted to Equation 1 (see section Experimental: Force spectroscopy on living cells). Because the Young’s modulus of the tip is about 160 GPa (seven orders of magnitude larger than that of the cells

Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

• Adam Sweetman and
• Andrew Stannard

Beilstein J. Nanotechnol. 2014, 5, 386–393, doi:10.3762/bjnano.5.45

• behaviour may be increased dramatically if a judicious knowledge of the tip structure is available, for example by use of in situ field ion microscopy (FIM), transmission electron microscopy (TEM), and/or scanning electron microscopy (SEM), on well-defined tips both before and after force spectroscopy

Exploring the complex mechanical properties of xanthan scaffolds by AFM-based force spectroscopy

• Hao Liang,
• Guanghong Zeng,
• Yinli Li,
• Shuai Zhang,
• Huiling Zhao,
• Lijun Guo,
• Bo Liu and
• Mingdong Dong

Beilstein J. Nanotechnol. 2014, 5, 365–373, doi:10.3762/bjnano.5.42

• structures were investigated by using AFM-based force spectroscopy (FS). In this work, three types of structures in the xanthan scaffold were identified based on three types of FS stretching events. The fact that the complex force responses are the combinations of different types of stretching events

• suggests complicated intermolecular interactions among xanthan fibrils. The results provide crucial information to understand the structures and mechanical properties of the xanthan scaffold. Keywords: atomic force microscopy (AFM); force spectroscopy (FS); mechanical properties; xanthan scaffold

• morphologies of xanthan-based materials, such as fibrils, networks [4] and ring-like structures [5], have been revealed by AFM imaging. Furthermore, AFM is a powerful tool for studying the mechanical properties on the nanoscale. AFM-based force spectroscopy (FS) has been applied to investigate the fingerprint

Noncontact atomic force microscopy II

• Mehmet Z. Baykara and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2014, 5, 289–290, doi:10.3762/bjnano.5.31

• insulating material surfaces of technological and scientific importance with atomic resolution, thus contributing to nano-scale science in a major way with each passing year. The capabilities of NC-AFM are not only limited to atomic-resolution imaging: Force spectroscopy allows characterization of

• uncovering the associated principles, which is reflected in a number of contributions. Additionally, three-dimensional force spectroscopy on adsorbed molecules as well as challenges associated with the correct incorporation of long-range forces in such experiments are emphasized. Finally, it becomes apparent