Multifrequency AFM integrating PeakForce tapping and higher eigenmodes for heterogeneous surface characterization

• Yanping Wei,
• Jiafeng Shen,
• Yirong Yao,
• Xuke Li,
• Ming Li and
• Peiling Ke

Beilstein J. Nanotechnol. 2025, 16, 2077–2085, doi:10.3762/bjnano.16.142

• stiffness (k) matching, a critical requirement for accurate contact mechanics models [20]. The stiffness k should be neither too large (to ensure a sufficient deflection signal for accurate force measurement) nor too small (to achieve adequate sample indentation). For heterogeneous samples with modulus

• stiffness, insufficient sample deformation led to significant variability in modulus measurements (Figure 3b), indicating the ScanAsyst-Air probe was unsuitable for reliable Young’s modulus quantification. Comparative analysis revealed a high degree of similarity in the topography, modulus, and adhesion

• reliable separation, while the stiff probe successfully discriminates (D ≈ 2.7). However, phase imaging with both probes enables effective differentiation between these regions, demonstrating that the eigenmode contrast is less dependent on probe stiffness compared to quantitative mechanics maps. To assess

Molecular and mechanical insights into gecko seta adhesion: multiscale simulations combining molecular dynamics and the finite element method

• Yash Jain,
• Saeed Norouzi,
• Tobias Materzok,
• Stanislav N. Gorb and
• Florian Müller-Plathe

Beilstein J. Nanotechnol. 2025, 16, 2055–2076, doi:10.3762/bjnano.16.141

• from the spatulae. To mitigate excessive deformation or drift, harmonic springs connect the FE nodes in the bridging domain to their initial positions at the start of each FEM iteration. These springs have a stiffness referred to as the FE-coupling spring constant. These FE-coupling harmonic springs

• of APs per BD averaged 395 ± 9.9, depending slightly on the local FE mesh geometry. Each AP coincided with a FE node and was linked to a nearby MD bead via a harmonic spring with stiffness (MD-coupling spring constant) 0.28 nN/nm. FE nodes in the BD were also coupled to their initial positions via

• springs with stiffness (FE-coupling spring constant) 0.08 nN/nm. Figure 7 illustrates a typical BD configuration, showing the overlapping domains, anchor points, and harmonic spring connections. Simulation Details and Parameters Iteration details Molecular dynamics We used the velocity-Verlet algorithm

Mechanical property measurements enabled by short-term Fourier-transform of atomic force microscopy thermal deflection analysis

• Thomas Mathias,
• Roland Bennewitz and
• Philip Egberts

Beilstein J. Nanotechnol. 2025, 16, 1952–1962, doi:10.3762/bjnano.16.136

• transformations, it was possible to fit the thermal resonance peak of the normal displacement to track the frequency and Q-factor of the cantilever during an experiment, using a similar process to that used to calibrate the normal bending stiffness of cantilevers. With this quantitative data, we have used the

• dynamic mechanics models relating the contact stiffness of the tip/cantilever pressing into a surface with the oscillation frequency of the cantilever and show that they did not accurately model the experiment. Several material combinations of tip and sample were examined; tip size and cantilever

• stiffness demonstrate that existing models cannot capture the physics of this problem. While concrete solutions to use analytical models to interpret CR-AFM data have not been found, a possible solution may include revisiting the analytical model to capture a potentially more complex system than the current

Low-temperature AFM with a microwave cavity optomechanical transducer

• Ermes Scarano,
• Elisabet K. Arvidsson,
• August K. Roos,
• Erik Holmgren,
• Riccardo Borgani,
• Mats O. Tholén and
• David B. Haviland

Beilstein J. Nanotechnol. 2025, 16, 1873–1882, doi:10.3762/bjnano.16.130

• deflection ζ in response to a force F at the frequency Ω: where is the resonance frequency and Γ = η/meff the damping rate, with meff, k and η being, respectively, effective mass, stiffness, and damping coefficient of the eigenmode. A key figure of merit of a force transducer is its force sensitivity

• frequency, where |χ(Ωm)|2 = meff/kη2, resulting in a minimum detectable force, It is worth noting that Equation 4 clarifies a recurring misconception. Decreasing stiffness k does not necessarily reduce Fmin. Rather, it relaxes the constraint on the detector’s added noise for the force sensor to operate in

• the thermally limited regime ≪ , where Fmin ≃ . Achieving this limit can be especially challenging at cryogenic temperatures. Heritier et al. achieved a record force sensitivity of 0.16 aN/ using a Si nanoladder with Ωm/2π = 5.5 kHz and stiffness k = 6.5 µN/m at T = 100 mK [20]. AFM usually requires

Self-assembly and adhesive properties of Pollicipes pollicipes barnacle cement protein cp19k: influence of pH and ionic strength

• Shrutika Sawant,
• Anne Marie Power and
• J. Gerard Wall

Beilstein J. Nanotechnol. 2025, 16, 1863–1872, doi:10.3762/bjnano.16.129

• stalk (peduncle) that anchors it to a surface [23]. Structural and biochemical analyses revealed that the cuticle is primarily composed of α-chitin, with indications of elastin-like proteins and collagen [23], and stiffness values comparable to those found in elastomers and in the soft cuticles of

Beyond the bilayer: multilayered hygroscopic actuation in pine cone scales

• Kim Ulrich,
• Max David Mylo,
• Tom Masselter,
• Fabian Scheckenbach,
• Sophia Fischerbauer,
• Martin Nopens,
• Silja Flenner,
• Imke Greving,
• Linnea Hesse and
• Thomas Speck

Beilstein J. Nanotechnol. 2025, 16, 1695–1710, doi:10.3762/bjnano.16.119

• the bending of bilayer geometries due to an overestimated contribution of sclerenchyma fiber stiffness. Geometries with discrete fibers embedded in a brown tissue matrix more accurately reproduced the bending angles observed in experiments. This highlights the importance of the chosen material

Bioinspired polypropylene-based functionally graded materials and metamaterials modeling the mistletoe–host interface

• Lina M. Rojas González,
• Naeim Ghavidelnia,
• Christoph Eberl and
• Max D. Mylo

Beilstein J. Nanotechnol. 2025, 16, 1592–1606, doi:10.3762/bjnano.16.113

• , allows for thermal and mechanical stresses to be controlled locally, is known as functionally graded materials (FGMs). By means of a gradual composition and microstructure, FGMs can reduce interfacial stress, allowing for precise tailoring of mechanical properties such as stiffness, strength, and

• metamaterials, even more complex and tailored mechanical properties can be achieved at multiple length scales [15]. This integration enables the creation of materials with unprecedented combinations of stiffness, strength, damping, and other mechanical characteristics, offering enhanced performance and

• versatility for a wide range of applications [16]. By strategically designing the gradient profiles within FGMs and integrating them into the hierarchical architectures of mechanical metamaterials, engineers can effectively program and manipulate the stiffness of the resulting structures at multiple length

Better together: biomimetic nanomedicines for high performance tumor therapy

• Imran Shair Mohammad,
• Gizem Kursunluoglu,
• Anup Kumar Patel,
• Hafiz Muhammad Ishaq,
• Cansu Umran Tunc,
• Dilek Kanarya,
• Mubashar Rehman,
• Omer Aydin and
• Yin Lifang

Beilstein J. Nanotechnol. 2025, 16, 1246–1276, doi:10.3762/bjnano.16.92

• , which directly correlates to the neoadjuvant treatment efficacy. To confirm this phenomenon, Zheng et al. constructed TNBC membrane-coated, artesunate-loaded PLGA NPs (231M-ARS@PLGA) to regulate the SWE stiffness via cancer-associated fibroblast (CAF) inhibition. In the MDA-MB 231 and E0771 orthotopic

• tumor models, 231M-ARS@PLGA reduced the SWE stiffness and tumor hypoxia, which potently enhanced the antitumor effects of OTX and PD1 inhibitor. Importantly, single-cell sequencing demonstrated two main CAFs (extracellular matrix and wound-healing CAFs) that produce extracellular matrix could influence

• the tumor SWE stiffness as well as the antitumor effect of drugs. Moreover, biomimetic NPs reduced the CAF status, which in turn attenuates tumor hypoxia by increasing inflammatory blood vessels and oxygen transport capacity. This confirmed the role of CAFs on SWE stiffness and antitumor efficacy

Mechanical stability of individual bacterial cells under different osmotic pressure conditions: a nanoindentation study of Pseudomonas aeruginosa

• Lizeth García-Torres,
• Idania De Alba Montero,
• Eleazar Samuel Kolosovas-Machuca,
• Facundo Ruiz,
• Sumati Bhatia,
• Jose Luis Cuellar Camacho and
• Jaime Ruiz-García

Beilstein J. Nanotechnol. 2025, 16, 1171–1183, doi:10.3762/bjnano.16.86

• within the first stages of nanoindentation, similar values in the slopes of the curves reflected a stable stiffness of about kB = 20 mN/m and turgor pressures of Pt = 12.1 kPa. Interestingly, a change in the nonlinear regime of the force curves and a gradual increase in maximal deformation by the AFM tip

• . Therefore, the pre-programed grid in FV defines the amount of information (number of nanoindentations per scanned line) taken from the sample surface and also its resolution. Typical parameters obtained using the FV mode are the height, stiffness, adhesion, elasticity modulus, and dissipation of the sample

• conditions. Of particular interest was the extraction and comparison of nanomechanical maps obtained in the low range of loading forces to quantify its morphology, membrane stiffness, Young’s modulus of elasticity and adhesion when PA was tested in hypotonic (Milli-Q water), isotonic (0.1 M phosphate

Piezoelectricity of hexagonal boron nitrides improves bone tissue generation as tested on osteoblasts

• Sevin Adiguzel,
• Nilay Cicek,
• Zehra Cobandede,
• Feray B. Misirlioglu,
• Hulya Yilmaz and
• Mustafa Culha

Beilstein J. Nanotechnol. 2025, 16, 1068–1081, doi:10.3762/bjnano.16.78

• nucleation of calcium and phosphate ions, imparting stiffness and resistance to bone. Additionally, collagen and noncollagenous matrix proteins contribute to bone formation by offering a scaffold for hydroxyapatite deposition [2][3]. Bone tissue consists of four main cell types: bone lining cells

Soft materials nanoarchitectonics: liquid crystals, polymers, gels, biomaterials, and others

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2025, 16, 1025–1067, doi:10.3762/bjnano.16.77

• of LLZO. Furthermore, the incorporation of LLZO has been observed to enhance the nanoindentation stiffness of the composite. These findings suggest that the application of organic ionic plastic crystals as solid electrolytes is feasible when the concentrations of lithium salt and LLZO are optimized

Multifunctional properties of bio-poly(butylene succinate) reinforced with multiwalled carbon nanotubes

• Volodymyr Krasinskyi,
• Krzysztof Bajer,
• Ludmila Dulebova,
• Nickolas Polychronopoulos,
• Oksana Krasinska and
• Daniel Kaczor

Beilstein J. Nanotechnol. 2025, 16, 1014–1024, doi:10.3762/bjnano.16.76

• mechanical strength and stiffness, improved the tribological properties by reducing friction, and increased the crystallization temperature. However, it also resulted in a decrease in elasticity. Morphological analysis confirmed the uniform dispersion of the nanotubes. These findings underscore the potential

• ] synthesized lowly filled PBS-based nanocomposites, namely, PBSA/SWCNTs and PBS/MWCNTs, respectively, via solution casting after the pre-modification of CNTs. At an SWCNT content of 0.5 wt % in PBSA, a twofold increase in PBS stiffness was observed, along with increased crystallization and glass transition

• transverse direction (TD). The addition of CNTs to PBS at a concentration of 0.5 wt % enhances the mechanical tensile strength and stiffness of the material (tensile modulus increases); however, it significantly reduces its elasticity, as evidenced by a 1.5–2.0 times decrease in relative elongation. The

Synthesis of a multicomponent cellulose-based adsorbent for tetracycline removal from aquaculture water

• Uyen Bao Tran,
• Ngoc Thanh Vo-Tran,
• Khai The Truong,
• Dat Anh Nguyen,
• Quang Nhat Tran,
• Huu-Quang Nguyen,
• Jaebeom Lee and
• Hai Son Truong-Lam

Beilstein J. Nanotechnol. 2025, 16, 728–739, doi:10.3762/bjnano.16.56

• hydroxy groups interact with the functional groups of the cross-linking agent, reducing the polymer’s water solubility while increasing its stiffness and chemical stability [35][36]. Glutaraldehyde (GA), a linear five-carbon dialdehyde, is regarded as a more effective cross-linking agent compared to

Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

• Nur Areisman Mohd Salleh,
• Amalina Muhammad Afifi,
• Fathiah Mohamed Zuki and
• Hanna Sofia SalehHudin

Beilstein J. Nanotechnol. 2025, 16, 286–307, doi:10.3762/bjnano.16.22

• modulus (or elastic modulus) is a measurement of elasticity, which describes the stiffness of nanofibers and is calculated as the ratio of stress to strain in the elastic deformation region, which is the slope of the initial linear region of the stress–strain curve. Elongation at break measures the extent

• as the additional parameter [140]. The presence of chitosan in PVA membranes is expected to increase the storage modulus because of the higher stiffness of chitosan chains compared to PVA chains, as reported from DMA tests by Parparita and coworkers [141]. Koosha et al. [59] measured the dynamic

• between polymer chains, resulting in structures that are stable under deformation, exhibiting high stiffness and mechanical elasticity. This process is often facilitated by agents such as glutaraldehyde [174], epichlorohydrin, genipin, and citric acid [164]. Physical cross-linking involves non-covalent

Advanced atomic force microscopy techniques V

• Philipp Rahe,
• Ilko Bald,
• Nadine Hauptmann,
• Regina Hoffmann-Vogel,
• Harry Mönig and
• Michael Reichling

Beilstein J. Nanotechnol. 2025, 16, 54–56, doi:10.3762/bjnano.16.6

• accurate knowledge of the quartz cantilever stiffness, the authors develop a method to quantify the stiffness based on thermal noise measurements and numerical simulation. Calibrated measurements of conductivity and resistivity are the focus of the contribution by Piquemal et al. [3]. A particular

Natural nanofibers embedded in the seed mucilage envelope: composite hydrogels with specific adhesive and frictional properties

• Agnieszka Kreitschitz and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2024, 15, 1603–1618, doi:10.3762/bjnano.15.126

• friction of mucilage just after hydration. In time series of measurements, the friction increased. The water loss from the mucilage caused an increase of its stiffness and adhesive properties [26]. The decreasing hydration level and the increasing viscosity of flax mucilage play an important role in the

Strain-induced bandgap engineering in 2D ψ-graphene materials: a first-principles study

• Kamal Kumar,
• Nora H. de Leeuw,
• Jost Adam and
• Abhishek Kumar Mishra

Beilstein J. Nanotechnol. 2024, 15, 1440–1452, doi:10.3762/bjnano.15.116

• remaining C–C bond lengths fluctuate as the applied strain level increases or decreases. It is known that the in-plane stiffness of ψ-graphene is higher than that of penta-graphene and is comparable to that of graphene [16]. Therefore, it can resist compressive strain (negative strain) in its lattice plane

Hymenoptera and biomimetic surfaces: insights and innovations

• Vinicius Marques Lopez,
• Carlo Polidori and
• Rhainer Guillermo Ferreira

Beilstein J. Nanotechnol. 2024, 15, 1333–1352, doi:10.3762/bjnano.15.107

• structural stiffness [104]. Research on biological membranes, inspired by the superior structures of insect wings, holds potential for advancements in various sectors, including medical, construction, aviation, and automotive industries [104][105][106][107][108]. Research on hymenopteran wings remains

New design of operational MEMS bridges for measurements of properties of FEBID-based nanostructures

• Bartosz Pruchnik,
• Krzysztof Kwoka,
• Ewelina Gacka,
• Dominik Badura,
• Piotr Kunicki,
• Andrzej Sierakowski,
• Paweł Janus,
• Tomasz Piasecki and
• Teodor Gotszalk

Beilstein J. Nanotechnol. 2024, 15, 1273–1282, doi:10.3762/bjnano.15.103

• . The silicon edges under the opMEMS bridge bases were defined to be vertical and precisely located, thanks to the lattice orientation. The opMEMS were 600 μm long, 100 μm wide, and 80 nm thick, with 40 nm of silicon nitride body and 40 nm of platinum paths on top. To reduce the stiffness of the opMEMS

• analyser to assess the properties of the active device. The measured level of vibration of the MEMS bridge at a known temperature allows its stiffness to be determined with an accuracy of 5% [38]. First, the thermomechanical noise of the structure vibration was measured, then the displacement of the

• spectral analysis of vibrations [49]. The thermomechanical noise analysis approximates the bridge as a simple harmonic oscillator with one DOF, as has been used for determining the spring constant of AFM cantilevers [50]. This approach provides an approximation for the stiffness k in terms of the measured

Functional morphology of cleaning devices in the damselfly Ischnura elegans (Odonata, Coenagrionidae)

• Silvana Piersanti,
• Gianandrea Salerno,
• Wencke Krings,
• Stanislav Gorb and
• Manuela Rebora

Beilstein J. Nanotechnol. 2024, 15, 1260–1272, doi:10.3762/bjnano.15.102

• nanoindentation tests, discovered that the tibial comb of honeybees exhibits a resilin gradient with a stiffness variation spanning nearly two orders of magnitude, ranging from approximately 25 MPa at the tip to around 645 MPa at the base. This gradient enhances the catapult effect, allowing the comb to produce

• increased inertia that counteracts the initially dominant adhesion, effectively dislodging attached pollen and dust. The same authors also developed an elastomeric bioinspired stiffness-gradient catapult and demonstrated its potential in practical applications, thus confirming that studies on the functional

Beyond biomimicry – next generation applications of bioinspired adhesives from microfluidics to composites

• Dan Sameoto

Beilstein J. Nanotechnol. 2024, 15, 965–976, doi:10.3762/bjnano.15.79

• degree of controllability or even its ability to self-support under gravitational loads; thus, there is a major interest in stiffness-tunable materials for soft robotic systems [15]. This stiffness tuning in many cases relies on the temporary bonding of composite layers or materials to change effective

• stiffness. While soft robotics have shown a need for stiffness-tunable materials, the ability for composites in and of themselves to be reversibly bonded potentially opens up a far greater industrial impact and applications in adaptable, smart materials. Even improved sustainability could be achieved if

• laminates and composites could be reformed and reused. The secret to improve use cases of reversible adhesives and to improve applications in the above three subfields is to use biomimetic materials to manufacture composites which, in turn, have the capacity to change their stiffness, shape, or other

The effect of age on the attachment ability of stick insects (Phasmatodea)

• Marie Grote,
• Stanislav N. Gorb and
• Thies H. Büscher

Beilstein J. Nanotechnol. 2024, 15, 867–883, doi:10.3762/bjnano.15.72

• increased stiffness are accompanied by the decreased ability to climb an incline [5][16]. Zhou et al. [17] found stiffer and darker “scars” on the pads of aged cockroaches, most likely due to accumulated damage, resulting in the pads not being as compliant as in younger cockroaches. Slifer [18] made similar

• stiffness of the cuticle of these organs and the internal pressure are important for the functionality and likely susceptible to decay during ageing [42][43]. We investigated the change in attachment ability and tarsal morphology in the species Sungaya aeta Hennemann, 2023 (Heteropterygidae). Members of

• surface in younger adult individuals. This effect vanished for older adult animals, as attachment forces became more similar on all three substrates. No change of nub morphology was observed in older animals (Figure 7G,I), but a change of stiffness of the nubs could potentially affect their functionality

Elastic modulus of β-Ga₂O₃ nanowires measured by resonance and three-point bending techniques

• Annamarija Trausa,
• Sven Oras,
• Sergei Vlassov,
• Mikk Antsov,
• Tauno Tiirats,
• Andreas Kyritsakis,
• Boris Polyakov and
• Edgars Butanovs

Beilstein J. Nanotechnol. 2024, 15, 704–712, doi:10.3762/bjnano.15.58

• the length of the NW. Three-point bending tests Three-point bending tests were performed by AFM (Dimension Edge, Bruker) using noncontact mode cantilevers with nominal stiffness of 42 N/m (NCHR-50, Nanosensors, Figure 6b). The NW lengths and widths for three-point bending were measured by SEM (Nova

Enhancing higher-order modal response in multifrequency atomic force microscopy with a coupled cantilever system

• Wendong Sun,
• Jianqiang Qian,
• Yingzi Li,
• Yanan Chen,
• Zhipeng Dou,
• Rui Lin,
• Peng Cheng,
• Xiaodong Gao,
• Quan Yuan and
• Yifan Hu

Beilstein J. Nanotechnol. 2024, 15, 694–703, doi:10.3762/bjnano.15.57

• . More details about the derivation process can be found in [19]. The final result for the transfer function G of the infinite product expansion is obtained as: where s is the (complex) Laplace variable, and m is the mass per unit length. EI and c are the flexural stiffness and the damping coefficient

Functional fibrillar interfaces: Biological hair as inspiration across scales

• Guillermo J. Amador,
• Brett Klaassen van Oorschot,
• Caiying Liao,
• Jianing Wu and
• Da Wei

Beilstein J. Nanotechnol. 2024, 15, 664–677, doi:10.3762/bjnano.15.55

• [113]. Intriguingly, even after attachment, having motile flagella still matters for the cell as it appears to enable sensing of substrate stiffness [114]. In addition to flagella, other hairs of E. coli include the type-I pili (frimbriae) and type-IV pili [113]. Collaboration between these hairs also

• –channel protein complex may provide mechanical gating to sense deflections of the mastigonemes caused by fluid flow [112]. Additionally, for bacteria, E. coli, their passive flagella have been linked to sensing the material stiffness of surfaces they attach to [114]. Clusters of hairs, or hair plates, on