Stiffening Response Research Articles

Stiffening of the Cytoplasm in Response to Intracellularly Applied Forces.

Cells constantly encounter mechanical forces that regulate various cellular functions, such as migration, division, and differentiation. Understanding how cells respond to forces at the intracellular level is essential for elucidating the mechanical adaptability of living cells. This study investigates how the cytoplasm alters its mechanical properties in response to forces applied inside a cell. The mechanical properties were measured through in situ characterization using magnetic tweezers to apply mechanical forces on magnetic beads internalized into cells. The findings reveal that the cytoplasm stiffens within seconds when force is applied to the cytoplasm. Macromolecular crowding and cytoskeletal structures, particularly F-actin, were found to significantly contribute to cytoplasm stiffening. The stiffening response was also observed across multiple length scales by using magnetic beads of varying diameters. These results highlight the rapid adaptation of the cytoplasm to mechanical forces applied to the inside of a cell.

Hard- and Soft-Coded Strain Stiffening in Metamaterials via Out-of-Plane Buckling Using Highly Entangled Active Hydrogel Elements.

Metamaterials show elaborate mechanical behavior such as strain stiffening, which stems from their unit cell design. However, the stiffening response is typically programmed in the design step and cannot be adapted postmanufacturing. Here, we show hydrogel metamaterials with highly programmable strain-stiffening responses by exploiting the out-of-plane buckling of integrated pH-switchable hydrogel actuators. The stiffening upon reaching a certain extension stems from the initially buckled active hydrogel beams. At low strain, the beams do not contribute to the mechanical response under tension until they straighten with a resulting step-function increase in stiffness. In the hydrogel actuator design, the acrylic acid concentration hard-codes the configuration of the metamaterial and range of possible stiffening onsets, while the pH soft-codes the exact stiffening onset point after fabrication. The utilization of out-of-plane buckling to realize subsequent stiffening without the need to deform the passive structure extends the application of hydrogel actuators in mechanical metamaterials. Our concept of out-of-plane buckled active elements that stiffen only under tension enables strain-stiffening metamaterials with high programmability before and after fabrication.

Effects of isotropic stress on the band structure elastic, optical, thermal, and x-ray diffraction properties of TiSnO3.

Cubic perovskite titanium stannous oxide (TiSnO3) is a promising material for various applications due to its functional properties. However, understanding how these properties change under external stress is crucial for its development and optimization. This study employed density functional theory calculations to investigate the structural, electronic, optical, thermal, and mechanical properties of TiSnO3 under varying degrees of external static isotropic stress (0-120 GPa). The study reveals a significant decrease in the bandgap of TiSnO3 with increasing stress due to lattice modifications and the formation of delocalized electrons. Partial density of states analysis indicates that Sn and O states play a key role in shaping the electronic band structure. TiSnO3 exhibits increased light absorption with stress, accompanied by a blue shift in absorption peaks, whereas, both polarizability and refractive index decrease with increasing stress. Mechanically, all elastic moduli (bulk, shear, and Young's) show an increase under stress, signifying a stiffening response of the material under stress. Similarly, the Pugh ratio suggests a transition from ductile to brittle behaviour at elevated stress levels. Phonon dispersion calculations indicate the instability of the cubic phase at 0 K. However, a phonon gap emerges at 30 GPa and widens with increasing stress. X-ray diffraction further supports these findings by demonstrating a shift in diffraction peaks towards higher angles with increasing stress, consistent with the applied stress. In conclusion, this computational study offers a thorough understanding of how external stress influences the properties of TiSnO3, providing valuable insights for potential applications in various fields.

Switchable microscale stress response of actin-vimentin composites emerges from scale-dependent interactions.

The mechanical properties of the mammalian cell regulate many cellular functions and are largely dictated by the cytoskeleton, a composite network of protein filaments, including actin, microtubules, and intermediate filaments. Interactions between these distinct filaments give rise to emergent mechanical properties that are difficult to generate synthetically, and recent studies have made great strides in advancing our understanding of the mechanical interplay between actin and microtubule filaments. While intermediate filaments play critical roles in the stress response of cells, their effect on the rheological properties of the composite cytoskeleton remains poorly understood. Here, we use optical tweezers microrheology to measure the linear viscoelastic properties and nonlinear stress response of composites of actin and vimentin with varying molar ratios of actin to vimentin. We reveal a surprising, nearly opposite effect of actin-vimentin network mechanics compared to single-component networks in the linear versus nonlinear regimes. Namely, the linear elastic plateau modulus and zero-shear viscosity are markedly reduced in composites compared to single-component networks of actin or vimentin, whereas the initial response force and stiffness are maximized in composites versus single-component networks in the nonlinear regime. While these emergent trends are indicative of distinct interactions between actin and vimentin, nonlinear stiffening and longtime stress response appear to both be dictated primarily by actin, at odds with previous bulk rheology studies. We demonstrate that these complex, scale-dependent effects arise from the varied contributions of network density, filament stiffness, non-specific interactions, and poroelasticity to the mechanical response at different spatiotemporal scales. Cells may harness this complex behavior to facilitate distinct stress responses at different scales and in response to different stimuli to allow for their hallmark multifunctionality.

Gradients of properties increase the morphing and stiffening performance of bioinspired synthetic fin rays

State-of-the-art morphing materials are either very compliant to achieve large shape changes (flexible metamaterials, compliant mechanisms, hydrogels), or very stiff but with infinitesimal changes in shape that require large actuation forces (metallic or composite panels with piezoelectric actuation). Morphing efficiency and structural stiffness are therefore mutually exclusive properties in current engineering morphing materials, which limits the range of their applicability. Interestingly, natural fish fins do not contain muscles, yet they can morph to large amplitudes with minimal muscular actuation forces from the base while producing large hydrodynamic forces without collapsing. This sophisticated mechanical response has already inspired several synthetic fin rays with various applications. However, most ‘synthetic’ fin rays have only considered uniform properties and structures along the rays while in natural fin rays, gradients of properties are prominent. In this study, we designed, modeled, fabricated and tested synthetic fin rays with bioinspired gradients of properties. The rays were composed of two hemitrichs made of a stiff polymer, joined by a much softer core region made of elastomeric ligaments. Using combinations of experiments and nonlinear mechanical models, we found that gradients in both the core region and hemitrichs can increase the morphing and stiffening response of individual rays. Introducing a positive gradient of ligament density in the core region (the density of ligament increases towards the tip of the ray) decreased the actuation force required for morphing and increased overall flexural stiffness. Introducing a gradient of property in the hemitrichs, by tapering them, produced morphing deformations that were distributed over long distances along the length of the ray. These new insights on the interplay between material architecture and properties in nonlinear regimes of deformation can improve the designs of morphing structures that combine high morphing efficiency and high stiffness from external forces, with potential applications in aerospace or robotics.

Effect of Cross-Link Homogeneity on the High-Strain Behavior of Elastic Polymer Networks.

Cross-link heterogeneity and topological defects have been shown to affect the moduli of polymer networks in the low-strain regime. Probing their role in the high-strain regime, however, has been difficult because of premature network fracture. Here, we address this problem by using a double-network approach to investigate the high-strain behavior of both randomly and regularly cross-linked networks with the same backbone chemistry. Randomly cross-linked poly(n-butyl acrylate) networks with target molecular weights between cross-links of 5-30 kg/mol were synthesized via free-radical polymerization, while regularly cross-linked poly(n-butyl acrylate) networks with molecular weights between cross-links of 7-38 kg/mol were synthesized via cross-linking of tetrafunctional star polymers. Both types of networks were then swollen in a monomer/cross-linker mixture, polymerized to form double networks, and characterized via uniaxial tensile testing. The onset of strain stiffening was found to occur later in regular networks than in random networks with the same modulus but was well-predicted by the target molecular weight between cross-links of each sample. These results indicate that the low- and high-strain behavior of polymer networks result from different molecular-scale features of the material and suggest that controlling network architecture offers new opportunities to both further fundamental understanding of architecture-property relationships and design materials with independently controlled moduli and strain stiffening responses.

Abstract 1122: Endothelial Cd36 Mediates Lipid-induced Stiffening Of Aortic Endothelium And Western Diet-induced Barrier Disruption

Introduction: Western diet (WD) associates with elevations in blood lipids. Endothelial cells (EC) uptake lipids through scavenger receptors such as CD36. In our studies we demonstrated that exposure to lipids induces a stiffening response in ECs, with in vivo studies showing that this stiffening is abrogated in mice with a global CD36 knockout. Hypothesis: WD associates with aortic barrier disruption. in vitro studies have demonstrated that EC stiffening correlates with barrier disruption. It is our hypothesis that EC stiffening mediates WD-induced aortic barrier disruption in an endothelial CD36-dependent manner. Methods: To generate a model of endothelial-specific CD36 deficiency, we crossed tamoxifen-inducible Cre mice with an EC-promoter with CD36 fl/fl mice. Cre only mice are employed as controls. At the end of the study window, aortas are excised for assessment of EC stiffening via atomic force microscopy. Separate cohorts are assessed for barrier disruption via quantification of Evans blue dye (EBD) leakage or VE-cadherin junctional thickness. Inhibition of CD36 in vitro was accomplished with SSO. For cell experiments we employed long-chain fatty acids (LCFAs), lipid ligands for CD36. Results: WD induced significant stiffening of the aortic endothelium [p<0.05]. This phenomenon was only observed in male (n=5-6) and not female (n=3-10) mice. EC stiffening associated with aortic barrier disruption as indicated by increased EBD permeation (n=3-8) and increased VE-cadherin thickness (n=3-4) [p<0.05]. Use of an endothelial-specific CD36 deficiency significantly abrogated stiffening and barrier disruption [p<0.05]. Controls demonstrated no effects by tamoxifen (n=2-3). Exposure to 5 μM of palmitic and stearic acids (saturated LCFAs) results in stiffening while exposure to oleic acid (unsaturated LCFA) does not (n=5-12) [p<0.05]. Palmitic acid-induced EC stiffening was shown to be dependent on CD36 (n=5-6) and activation of RhoA protein kinase (n=3-8) [p<0.05]. Conclusions: Our results demonstrate that endothelial CD36 is required for WD-induced EC stiffening and subsequent disruption of the aortic barrier. Furthermore, our results suggest that CD36 mediates EC stiffening through its role as scavenger receptor to saturated LCFAs.

A Novel Experimental Approach for the Measurement of Vibration-Induced Changes in the Rheological Properties of Ex Vivo Ovine Brain Tissue.

Increased incidence of traumatic brain injury (TBI) imposes a growing need to understand the pathology of brain trauma. A correlation between the incidence of multiple brain traumas and rates of behavioural and cognitive deficiencies has been identified amongst people that experienced multiple TBI events. Mechanically, repetitive TBIs may affect brain tissue in a similar way to cyclic loading. Hence, the potential susceptibility of brain tissue to mechanical fatigue is of interest. Although temporal changes in ovine brain tissue viscoelasticity and biological fatigue of other tissues such as tendons and arteries have been investigated, no methodology currently exists to cyclically load ex vivo brain tissue. A novel rheology-based approach found a consistent, initial stiffening response of the brain tissue before a notable softening when subjected to a subsequential cyclic rotational shear. History dependence of the mechanical properties of brain tissue indicates susceptibility to mechanical fatigue. Results from this investigation increase understanding of the fatigue properties of brain tissue and could be used to strengthen therapy and prevention of TBI, or computational models of repetitive head injuries.

Thermoresponsive Injectable Hydrogel To Mimic the Heat- and Strain-Stiffening Behavior of Biopolymers toward Muscle Cell Proliferation.

Injectable hydrogels with nonlinear mechanical attributes to emulate natural biopolymers hold paramount significance in tissue engineering, offering the potential to create scaffolds that seamlessly mimic the biomechanical intricacies of living tissues. Herein, we unveil a synthetic design strategy employing Schiff base chemistry to furnish a peptide-polymer hierarchical contractile injectable hydrogel network. This innovative design demonstrates cross-linking of supramolecular peptide nanostructures such as nanofibers, 1NF, and twisted bundles, 1TB, with a thermosensitive aldehyde-functionalized polymer, PCHO. These networks exhibit interesting nonlinear mechanical stiffening responses to temperature and external stress. Furthermore, the hydrogels transform into a gel state at physiological temperature to exhibit injectable behavior and demonstrate compression load-bearing capabilities. Finally, the hydrogel network exhibits excellent biocompatibility and cell proliferation toward fibroblast, L929, and myoblast, C2C12, to validate their use as potential extracellular matrix mimetic injectable scaffolds.

Oscillatory rheometry for elucidating the influence of non-network biopolymer aggregation on pectin-gelatin composite gels

Gel networks formed from biopolymers have intrigued rheological interest, especially in the food industry. Despite ubiquitous non-network biopolymer aggregation in real gel food systems, its fundamental rheological implications remain less understood. This study addresses this by preparing pectin-gelatin composite gels with dispersed or aggregated biopolymers and comparatively analyzing viscoelastic responses using rheometry. Subtle discrepancies in non-network biopolymer states were revealed through oscillatory shearing at different frequencies and amplitudes. Biopolymer aggregation in the network notably influenced loss tangent frequency dependency, particularly at high frequencies, elevating I3/I1 values and sensitizing the yield point. Non-network biopolymers weakened Payne effects and gel non-linearity. A combination of strain stiffening and shear thinning nonlinear responses characterized prepared gel systems. Aggregation of pectin and gelatin enhanced shear thinning, while strain stiffening was notable in highly aggregated pectin cases. This study enhances understanding of the link between non-network structural complexity and viscoelastic properties in oscillatory rheometry of food gels.

Living cells as a biological analog of optical tweezers - a non-invasive microrheology approach.

Microrheology, the study of fluids on micron length-scales, promises to reveal insights into cellular biology, including mechanical biomarkers of disease and the interplay between biomechanics and cellular function. Here a minimally-invasive passive microrheology technique is applied to individual living cells by chemically binding a bead to the surface of a cell, and observing the mean squared displacement of the bead at timescales ranging from milliseconds to 100s of seconds. Measurements are repeated over the course of hours, and presented alongside analysis to quantify changes in the cells' low-frequency elastic modulus, G0', and the cell's dynamics over the time window ∼10-2s to 10s. An analogy to optical trapping allows verification of the invariant viscosity of HeLa S3 cells under control conditions and after cytoskeletal disruption. Stiffening of the cell is observed during cytoskeletal rearrangement in the control case, and cell softening when the actin cytoskeleton is disrupted by Latrunculin B. These data correlate with conventional understanding that integrin binding and recruitment triggers cytoskeletal rearrangement. This is, to our knowledge, the first time that cell stiffening has been measured during focal adhesion maturation, and the longest time over which such stiffening has been quantified by any means. STATEMENT OF SIGNIFICANCE: Here, we present an approach for studying mechanical properties of live cells without applying external forces or inserting tracers. Regulation of cellular biomechanics is crucial to healthy cell function. For the first time in literature, we can non-invasively and passively quantify cell mechanics during interactions with functionalised surface. Our method can monitor the maturation of adhesion sites on the surface of individual live cells without disrupting the cell mechanics by applying forces to the cell. We observe a stiffening response in cells over tens of minutes after a bead chemically binds. This stiffening reduces the deformation rate of the cytoskeleton, although the internal force generation increases. Our method has potential for applications to study mechanics during cell-surface and cell-vesicle interactions.

Intelligent Polymers for Multi-Functional Applications: Mechanical and Electrical Aspects.

In this study, we fabricated an intelligent material, shear stiffening polymer (SSP), and reinforced it with carbon nanotube (CNT) fillers to obtain intelligent mechanical and electrical properties. The SSP was enhanced with multi-functional behavior, such as electrical conductivity and stiffening texture. Various amounts of CNT fillers were distributed in this intelligent polymer up to a loading rate of 3.5 wt%. The mechanical and electrical aspects of the materials were investigated. Regarding the mechanical properties, dynamic mechanical analysis was carried out, as well as conducting shape stability and free-fall tests. Viscoelastic behavior was investigated in the dynamic mechanical analysis, whereas cold-flowing and dynamic stiffening responses were studied in shape stability and free-fall tests, respectively. On the other hand, electrical resistance measurements were carried out to understand the conductive behavior of the polymers of the electrical properties. Based on these results, CNT fillers enhance the elastic nature of the SSP while initiating the stiffening behavior at lower frequencies. Moreover, CNT fillers provide higher shape stability, hindering the cold flow in the material. Lastly, SSP gained an electrically conductive nature from the CNT fillers.

The Strain Rate Effects of Coral Sand at Different Relative Densities and Moisture Contents.

A 37-mm-diameter split Hopkinson pressure bar (SHPB) apparatus was used for impact loading tests to determine the effects of the relative density and moisture content on the dynamic properties of coral sand. The stress-strain curves in the uniaxial strain compression state were obtained for different relative densities and moisture contents under strain rates between 460 s-1 and 900 s-1. The results indicated that with an increase in the relative density, the strain rate becomes more insensitive to the stiffness of the coral sand. This was attributed to the variable breakage-energy efficiency at different compactness levels. Water affected the initial stiffening response of the coral sand, and the softening was correlated with the strain rate. Strength softening due to water lubrication was more significant at higher strain rates due to the higher frictional dissipation. The volumetric compressive response of the coral sand was investigated by determining the yielding characteristics. The form of the constitutive model has to be changed to the exponential form, and different stress-strain responses should be considered. We discuss the effects of the relative density and water content on the dynamic mechanical properties of coral sand and clarify the correlation with the strain rate.

Bioinspired Fiber Networks With Tunable Mechanical Properties by Additive Manufacturing

Abstract Soft bioinspired fiber networks offer great potential in biomedical engineering and material design due to their adjustable mechanical behaviors. However, existing strategies to integrate modeling and manufacturing of bioinspired networks do not consider the intrinsic microstructural disorder of biopolymer networks, which limits the ability to tune their mechanical properties. To fill in this gap, we developed a method to generate computer models of aperiodic fiber networks mimicking type I collagen ready to be submitted for additive manufacturing. The models of fiber networks were created in a scripting language wherein key geometric features like connectivity, fiber length, and fiber cross section could be easily tuned to achieve desired mechanical behavior, namely, pretension-induced shear stiffening. The stiffening was first predicted using finite element software, and then a representative network was fabricated using a commercial 3D printer based on digital light processing technology using a soft resin. The stiffening response of the fabricated network was verified experimentally on a novel test device capable of testing the shear stiffness of the specimen under varying levels of uniaxial pretension. The resulting data demonstrated clear pretension-induced stiffening in shear in the fabricated network, with uniaxial pretension of 40% resulting in a factor of 2.65 increase in the small strain shear stiffness. The strategy described in this article addresses current challenges in modeling bioinspired fiber networks and can be readily integrated with advances in fabrication technology to fabricate materials truly replicating the mechanical response of biopolymer networks.

Tunable Mechanical Response of Self-Assembled Nanoparticle Superlattices.

Self-assembled nanoparticle superlattices (NPSLs) are an emergent class of self-architected nanocomposite materials that possess promising properties arising from precise nanoparticle ordering. Their multiple coupled properties make them desirable as functional components in devices where mechanical robustness is critical. However, questions remain about NPSL mechanical properties and how shaping them affects their mechanical response. Here, we perform in situ nanomechanical experiments that evidence up to an 11-fold increase in stiffness (∼1.49 to 16.9 GPa) and a 5-fold increase in strength (∼88 to 426 MPa) because of surface stiffening/strengthening from shaping these nanomaterials via focused-ion-beam milling. To predict the mechanical properties of shaped NPSLs, we present discrete element method (DEM) simulations and an analytical core-shell model that capture the FIB-induced stiffening response. This work presents a route for tunable mechanical responses of self-architected NPSLs and provides two frameworks to predict their mechanical response and guide the design of future NPSL-containing devices.

Effects of arm movement strategies on emotional state and balance control during height-induced postural threat in young adults

BackgroundIt is firmly established that postural threat seems to lead to an increased reliance on an ankle control (‘stiffening’) strategy. However, little is known about how postural threat affects performance in challenging tasks that require the use of upper body postural control strategies for stability. It is logical to assume that in such conditions, being able to utilise an upper body strategy may reduce the reliance on such ankle stiffening strategy. Research questionThe objective of this study was to determine how arm movement influences balance control during a challenging balance task performed under conditions of postural threat. MethodsThirty young adults (mean ± SD age; 22.0 ± 4.0 years) balanced in tandem stance whilst standing at both ground-level (no threat) and 0.8 m above ground (threat). In both conditions, participants performed the task under two different arm positions: restricted arm movements and free arm movements. Postural sway amplitude and frequency were calculated to infer postural stiffening response. Self-reported emotional responses were quantified by assessing balance confidence, fear of falling, perceived stability, and conscious balance processing. ResultsIndependent of arm movements, postural threat evoked an increase in fear of falling and conscious balance processing, and reductions in balance confidence and perceived stability. These threat-related changes in emotional state were further amplified when arm movements were restricted. Whilst significant increases in sway frequency during threat were observed in both arm conditions, reductions in sway amplitude were only observed during the restricted arm movement condition. SignificanceWe propose that these responses likely reflect a fear-related cautious strategy intended to reduce the postural destabilisation associated with individuals being unable to use their arms to counter any destabilisation, as would normally be the case in daily life.

Shear flow capacity of stiffened flanges in steel box girders

The purpose of this paper is to model the shear flow capacity of stiffened flange in a steel box girder. The present study uses an energy-based variational approach to analyze the steel box girder. A new parameter is introduced that is strongly correlated to the shear lag response of stiffeners to flanges. This parameter is named as shear flow parameter. The shear flow parameter decreases with increasing stiffener area to flange area ratio. Along with increasing the stiffness of the flange, stiffeners also reduce the shear flow capacity of the flange plate. It is observed that the reduced shear flow capacity causes more shear lag in the flange, increasing the stress at the web-flange junction. As a result of a high percentage of longitudinal stiffeners, steel box girders have a small effective width ratio, high negative shear lag effect, and significant deflection. This approach is in close agreement with experimental results, finite element results and theoretical results.

Influence of Metal Cations on the Viscoelastic Properties of Escherichia coli Biofilms.

Biofilms frequently cause complications in various areas of human life, e.g., in medicine and in the food industry. More recently, biofilms are discussed as new types of living materials with tunable mechanical properties. In particular, Escherichia coli produces a matrix composed of amyloid-forming curli and phosphoethanolamine-modified cellulose fibers in response to suboptimal environmental conditions. It is currently unknown how the interaction between these fibers contributes to the overall mechanical properties of the formed biofilms and if extrinsic control parameters can be utilized to manipulate these properties. Using shear rheology, we show that biofilms formed by the E. coli K-12 strain AR3110 stiffen by a factor of 2 when exposed to the trivalent metal cations Al(III) and Fe(III), while no such response is observed for the bivalent cations Zn(II) and Ca(II). Strains producing only one matrix component did not show any stiffening response to either cation or even a small softening. No stiffening response was further observed when strains producing only one type of fiber were co-cultured or simply mixed after biofilm growth. These results suggest that the E. coli biofilm matrix is a uniquely structured composite material when both matrix fibers are produced from the same bacterium. While the exact interaction mechanism between curli, phosphoethanolamine-modified cellulose, and trivalent metal cations is currently not known, our results highlight the potential of using extrinsic parameters to understand and control the interplay between biofilm structure and mechanical properties. This will ultimately aid in the development of better strategies for controlling biofilm growth.

DYNAMIC CHARACTERISTICS OF MIXTURE UNIFIED GRADIENT ELASTIC NANOBEAMS

The mixture unified gradient theory of elasticity is invoked for the rigorous analysis of the dynamic characteristics of elastic nanobeams. A consistent variational framework is established and the boundary-value problem of dynamic equilibrium enriched with proper form of the extra non-standard boundary conditions is detected. As a well-established privilege of the stationary variational theorems, the constitutive laws of the resultant fields cast as differential relations. The wave dispersion response of elastic nano-sized beams is analytically addressed and the closed form solution of the phase velocity is determined. The free vibrations of the mixture unified gradient elastic beam is, furthermore, analytically studied. The dynamic characteristics of elastic nanobeams is numerically evaluated, graphically illustrated, and commented upon. The efficacy of the established augmented elasticity theory in realizing the softening and stiffening responses of nano-sized beams is evinced. New numerical benchmark is detected for dynamic analysis of elastic nanobeams. The established mixture unified gradient elasticity model provides a practical approach to tackle dynamics of nano-structures in pioneering MEMS/NEMS.

Fatigue-free artificial ionic skin toughened by self-healable elastic nanomesh

Robust ionic sensing materials that are both fatigue-resistant and self-healable like human skin are essential for soft electronics and robotics with extended service life. However, most existing self-healable artificial ionic skins produced on the basis of network reconfiguration suffer from a low fatigue threshold due to the easy fracture of low-energy amorphous polymer chains with susceptible crack propagation. Here we engineer a fatigue-free yet fully healable hybrid ionic skin toughened by a high-energy, self-healable elastic nanomesh, resembling the repairable nanofibrous interwoven structure of human skin. Such a design affords a superhigh fatigue threshold of 2950 J m−2 while maintaining skin-like compliance, stretchability, and strain-adaptive stiffening response. Moreover, nanofiber tension-induced moisture breathing of ionic matrix leads to a record-high strain-sensing gauge factor of 66.8, far exceeding previous intrinsically stretchable ionic conductors. This concept creates opportunities for designing durable ion-conducting materials that replicate the unparalleled combinatory properties of natural skins more precisely.