"Ionically Conductive Elastic Polymer Binder for Ultrahigh Loading Electrode in High-Energy-Density Lithium Batteries"
https://doi.org/doi:10.1002/adma.202506266
https://pubmed.ncbi.nlm.nih.gov/40622247/
#Mechanical #Adhesion
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Rolling Down Soft Surfaces
Place a rigid ball on a hard vertical surface, and it will free fall. Stick a liquid drop there, and it will slide down. But researchers discovered that with a soft sphere and a soft surface, it’s possible to roll down a vertical wall. The effect requires just the right level of squishiness for both the wall and sphere, but when conditions are right, the 1-millimeter radius sphere rolls (with a little slipping) down the wall.
Rolling requires torque, something that’s usually lacking on a vertical surface. But the team found that their soft spheres got the torque needed to roll from their asymmetric contact with the surface. More of the sphere contacted above its centerline than below it. The researchers compared the way the sphere contacted the surface to a crack opening (at the back of the sphere) and a crack closing (at the front of the sphere). That asymmetry creates just enough torque to roll the sphere slowly. The team hopes their discovery opens up new possibilities for soft robots to climb and descend vertical surfaces. (Image and research credit: S. Mitra et al.; via Gizmodo)
"Static friction of liquid marbles"
https://arxiv.org/abs/2506.20116 #Physics.Flu-Dyn #Cond-Mat.Soft #Adhesion #Forces
arXiv.orgStatic friction of liquid marblesLiquid marbles, droplets coated with a granular layer, are highly mobile as particles prevent capillary adhesion with the substrate. Yet, they exhibit static friction due to their granular shell, which resists rolling until it yields. This friction depends on the shell geometry and increases exponentially with grain density, indicating a logistic dependence of interparticle compressive forces on surface coverage, confirmed by yielding measurements in granular rafts. These results reveal the shell's dual role, and establish liquid marbles as a model system for probing granular raft mechanics.
Evaporating Off Butterfly Scales
This award-winning macro video shows scattered water droplets evaporating off a butterfly‘s wing. At first glance, it’s hard to see any motion outside of the camera’s sweep, but if you focus on one drop at a time, you’ll see them shrinking. For most of their lifetime, these tiny drops are nearly spherical; that’s due to the hydrophobic, water-shedding nature of the wing. But as the drops get smaller and less spherical, you may notice how the drop distorts the scales it adheres to. Wherever the drop touches, the wing scales are pulled up, and, when the drop is gone, the scales settle back down. This is a subtle but neat demonstration of the water’s adhesive power. (Video and image credit: J. McClellan; via Nikon Small World in Motion)
Water droplets evaporate from the wing of a peacock butterfly. "E-cadherin negatively regulates hESCs endodermal differentiation under varied substrate stiffnesses"
https://doi.org/doi:10.1007/s00018-025-05776-9
https://pubmed.ncbi.nlm.nih.gov/40549002/
#Mechanical #Adhesion #Cadherin
SpringerLinkE-cadherin negatively regulates hESCs endodermal differentiation under varied substrate stiffnesses - Cellular and Molecular Life SciencesIntercellular adhesion is crucial in regulating stemness maintenance and differentiation initiation of embryonic stem cells (ESCs), which is also cooperated with extracellular mechanical microenvironment. Here an in vitro model was used to elucidate the effects of E-cadherin complexes on definitive endoderm (DE)-directed differentiation of hESCs (H1 cells), when the cells were seeded on polyacrylamide hydrogels with varied stiffnesses. Results indicated that stiff substrate increased the proportion of H1 cells differentiating into DE cells and intercellular E-cadherin expression was reduced with progressive stages at same stiffness, presenting a negative correlation of E-cadherin expression with differentiating progress or substrate stiffness. Blocking E-cadherin enhanced the productivity of differentiated cells and promoted the disassembly of intercellular adhesions by translocating YAP into nuclei, which was positively correlated with GATA6 and CXCR4 expressions in a stiffness-dependent manner. This work provided an insight into understanding the roles of E-cadherin-related intercellular adhesion and substrate stiffness in DE-directed differentiation of hESCs.
"Catechol-polysaccharide complex enhancing the detachment and blood coagulation of polyvinyl alcohol/chitosan cryogel for non-compressible bleeding"
https://doi.org/doi:10.1016/j.ijbiomac.2025.145281
https://pubmed.ncbi.nlm.nih.gov/40532994/
#Mechanical #Adhesion
doi.orgCatechol-polysaccharide complex enhancing the detachment and blood coagulation of polyvinyl alcohol/chitosan cryogel for non-compressible bleedingAs an efficient hemostatic material for non-compressible bleeding, the abilities of forming strong physical barrier and effectively activating coagula…
"Reduced nephrin tyrosine phosphorylation impairs podocyte force transmission and accelerates detachment in disease"
https://doi.org/doi:10.1016/j.isci.2025.112673
https://pubmed.ncbi.nlm.nih.gov/40510123/
#Mechanical #Adhesion #Force
doi.orgReduced nephrin tyrosine phosphorylation impairs podocyte force transmission and accelerates detachment in diseasePodocytes are specialized kidney cells that form the slit diaphragm (SD), an intercellular filtration barrier against plasma protein loss. The SD is s…
"The Mechanical Properties of Breast Cancer Cells and Their Surrounding Microenvironment"
https://doi.org/doi:10.3390/ijms26115183
https://pubmed.ncbi.nlm.nih.gov/40507992/
#Mechanical #Adhesion
"Tuning viscoelasticity and fine structure of living materials via synthetic adhesion logic and rheological perturbations"
https://doi.org/doi:10.1101/2025.06.04.657808
https://pubmed.ncbi.nlm.nih.gov/40501872/
#Mechanical #Adhesion #Cell
bioRxiv · Tuning viscoelasticity and fine structure of living materials via synthetic adhesion logic and rheological perturbationsEngineered living materials (ELMs) at the multicelluar level represent an innovation that promises programmable properties for biomedical, environmental, and consumer applications. However, the rational tuning of the mechanical properties of such ELMs from first principles remains a challenge. Here we use synthetic cell-cell adhesins to systematically characterize how rheological and viscoelastic properties of multicellular materials made from living bacteria can be tuned via adhesin strength, cell size and shape, and adhesion logic. We confirmed that the previous results obtained for non-living materials also apply to bacterial ELMs. Additionally, the incorporation of synthetic adhesins, combined with the adaptability of bacterial cells in modifying various cellular parameters, now enables novel and precise control over material properties. Furthermore, we demonstrate that rheology is a powerful tool for actively shaping the microscopic structure of ELMs, enabling control over cell aggregation and particle rearrangement, a key feature for complex material design. These results deepen our understanding of tuning the viscoelastic properties and fine structure of ELMs for applications like bioprinting and microbial consortia design including natural systems.
### Competing Interest Statement
The authors have declared no competing interest.
NSF, 2214020, 2229070, 2143126
NIH, GM145893
"The enteric nervous system is 10 times stiffer than the brain"
https://arxiv.org/abs/2506.08583 #Physics.Bio-Ph #Mechanical #Adhesion #Q-Bio.Nc
arXiv.orgThe enteric nervous system is 10 times stiffer than the brainNeural tissues of the central nervous system are among the softest and most fragile in the human body, protected from mechanical perturbation by the skull and the spine. In contrast, the enteric nervous system is embedded in a compliant, contractile tissue and subject to chronic, high-magnitude mechanical stress. Do neurons and glia of the enteric nervous system display specific mechanical properties to withstand these forces? Using nano-indentation combined with immunohistochemistry and second harmonic generation imaging of collagen, we discovered that enteric ganglia in adult mice are an order of magnitude more resistant to deformation than brain tissue. We found that glia-rich regions in ganglia have a similar stiffness to neuron-rich regions and to the surrounding smooth muscle, of ~3 kPa at 3 $μ$m indentation depth and of ~7 kPa at 8 $μ$m depth. Differences in the adhesion strength of the different tissue layers to the glass indenter were scarce. The collagen shell surrounding ganglia and inter-ganglionic fibers may play a key role in strengthening the enteric nervous system to resist the manifold mechanical challenges it faces.
"The Desmoglein 2 interactome in primary neonatal cardiomyocytes"
https://www.biorxiv.org/content/10.1101/2025.06.09.658637v1?rss=1 #Mechanical #Adhesion
bioRxiv · The Desmoglein 2 interactome in primary neonatal cardiomyocytesMechanical coupling and chemical communication between cardiomyocytes are facilitated through a specialized adhesive structure known as the intercalated disc (ICD). The ICD is essential for heart organization and contraction. Yet, the network of adhesion, adaptor, and signaling proteins that form the ICD remains poorly defined. Here, we combined proximity labeling and quantitative mass spectrometry to identify proteins associated with the desmosomal cadherin, Desmoglein 2 (DSG2), in cultured neonatal cardiomyocytes. We identified over 300 proteins in the DSG2 interactome; half of which are shared with the N-cadherin (CDH2) interactome in cardiomyocytes. Proteins unique to DSG2 include the gap junction protein connexin 43 and the plakin family of cytolinker proteins. Comparison of the cardiomyocyte DSG2 interactome with the interactomes of desmosomal proteins from epithelia revealed only a small number of shared proteins. In cardiomyocytes, plakoglobin (JUP) and plakophilin 2 (PKP2) were the most abundant shared proteins between the DSG2 and CDH2 interactomes. PKP2 is a dynamic protein whose membrane recruitment in cardiomyocytes is tension-dependent. Our analysis of the DSG2 interactome provides a critical new dimension to the proteomic atlas of the essential molecular complexes required for cardiomyocyte adhesion.
### Competing Interest Statement
The authors have declared no competing interest.
National Heart Lung and Blood Institute, https://ror.org/012pb6c26, HL127711
"Stochastic elastohydrodynamics of adhesion and phase separation during cell-cell contact across a viscous channel"
https://arxiv.org/abs/2506.05906 #Physics.Bio-Ph #Cond-Mat.Soft #Dynamics #Adhesion
arXiv.orgStochastic elastohydrodynamics of adhesion and phase separation during cell-cell contact across a viscous channelContact between fluctuating, fluid-lubricated soft surfaces is prevalent in engineering and biological systems, a process starting with adhesive contact, which can give rise to complex coarsening dynamics. One representation of such a system, which is relevant to biological membrane adhesion, is a fluctuating elastic interface covered by adhesive molecules that bind and unbind to a solid substrate across a narrow gap filled with a viscous fluid. This flow is described by the stochastic elastohydrodynamics thin-film equation, which combines the effects of viscous nanometric thin film flow, elastic membrane properties, adhesive springs, and thermal fluctuations. The average time it takes the fluctuating elastic membrane to adhere is predicted by the rare event theory, increasing exponentially with the square of the initial gap height. Numerical simulations reveal a phase separation of membrane domains driven by the binding and unbinding of adhesive molecules. The coarsening process displays close similarities to classical Ostwald ripening; however, the inclusion of hydrodynamics affects power-law growth. In particular, we identify a new bending-dominated coarsening regime, which is slower than the well-known tension-dominated case.
"Association of RhoGEF Ect2 with Desmoplakin Supports RhoA Activity at Intercellular Junctions: Implications for Carvajal Disease"
https://doi.org/doi:10.1101/2025.05.21.655405
https://pubmed.ncbi.nlm.nih.gov/40475587/
#Mechanical #Adhesion
bioRxiv · Association of RhoGEF Ect2 with Desmoplakin Supports RhoA Activity at Intercellular Junctions: Implications for Carvajal DiseaseDesmoplakin (DP) is an essential component of the desmosomal adhesion complex, tethering intermediate filaments to sites of intercellular adhesion to confer mechanical integrity to tissues. As a frequent target for mutation in cardiocutaneous syndromes that vary widely in phenotype, DP’s roles as a signaling hub are rapidly emerging. Here, we identify the RhoGEF Ect2 as a previously unappreciated binding partner of the desmosomal protein DP. DP is required for the localization of Ect2 to keratinocyte desmosomes and cardiac intercalated discs in vitro and in vivo, where it maintains active RhoA (Rho-GTP) at the membrane. We demonstrate further that Ect2 activity is supported by PKC in a DP-dependent manner in cardiac myocytes. Finally, a truncated form of DP expressed in patients with Carvajal syndrome associated with severe cardiocutaneous defects is impaired in its ability to bind and localize Ect2 to cell junctions in cardiomyocytes and keratinocytes isolated from patients. Our findings delineate an important relationship between a component of the desmosome and a critical regulator of actin cytoskeletal remodeling that could have widespread implications for understanding cardiac and cutaneous health and disease pathogenesis.
### Competing Interest Statement
F.S. was a co-founder of Stelios Therapeutics Inc. (acquired by LEXEO Therapeutics Inc.) and is a co-founder and shareholder of Papillon Therapeutics Inc and MyoTherapeutix Inc as well as is a consultant and shareholder of LEXEO Therapeutics Inc.
NIH NIAMS, AR041836, AR043380, F32AR081677
NIH NCI, CA228196
NIH NHLBI, HL142251, HL162369
American Heart Association
"Tuning viscoelasticity and fine structure of living materials via synthetic adhesion logic and rheological perturbations"
https://www.biorxiv.org/content/10.1101/2025.06.04.657808v1?rss=1 #Mechanical #Adhesion #Cell
bioRxiv · Tuning viscoelasticity and fine structure of living materials via synthetic adhesion logic and rheological perturbationsEngineered living materials (ELMs) at the multicelluar level represent an innovation that promises programmable properties for biomedical, environmental, and consumer applications. However, the rational tuning of the mechanical properties of such ELMs from first principles remains a challenge. Here we use synthetic cell-cell adhesins to systematically characterize how rheological and viscoelastic properties of multicellular materials made from living bacteria can be tuned via adhesin strength, cell size and shape, and adhesion logic. We confirmed that the previous results obtained for non-living materials also apply to bacterial ELMs. Additionally, the incorporation of synthetic adhesins, combined with the adaptability of bacterial cells in modifying various cellular parameters, now enables novel and precise control over material properties. Furthermore, we demonstrate that rheology is a powerful tool for actively shaping the microscopic structure of ELMs, enabling control over cell aggregation and particle rearrangement, a key feature for complex material design. These results deepen our understanding of tuning the viscoelastic properties and fine structure of ELMs for applications like bioprinting and microbial consortia design including natural systems.
### Competing Interest Statement
The authors have declared no competing interest.
NSF, 2214020, 2229070, 2143126
NIH, GM145893
"Learning to crawl: benefits and limits of centralized vs distributed control"
https://arxiv.org/abs/2506.02766 #Physics.Bio-Ph #Dynamics #Adhesion
arXiv.orgLearning to crawl: benefits and limits of centralized vs distributed controlWe present a model of a crawler consisting of several suckers distributed along a straight line and connected by springs. Both proprioception and control are binary: the system responds to the elongation vs compression of its springs and the suckers can either adhere or remain idle. A central pattern generator delivers a traveling wave of compression, and the crawler is tasked to learn how to control adhesion to effectively ride the wave in order to crawl. We ask what are the benefits and limitations of distributed vs centralized learning architectures. Using tabular Q-learning we demonstrate that crawling can be learned by trial and error in a purely distributed setting where each sucker learns independently how to control adhesion, with no exchange of information among them. We find that centralizing control of all suckers enhances speed and robustness to failure by orchestrating smoother collective dynamics and partly overcoming the limitations of rudimentary proprioception and control. However, since the computational cost scales exponentially with the number of suckers, centralized control quickly becomes untreatable with the size of the crawler. We then show that intermediate levels of centralization, where multiple control centers coordinate subsets of suckers, can negotiate fast and robust crawling while avoiding excessive computational burden. Our model can be further generalized to explore the trade-offs between crawling speed, robustness to failure, computational cost and information exchange that shape the emergence of biological solutions for crawling and could inspire the design of robotic crawlers.
"Tissue-Adhesive and Biocompatible Zein-Polyaniline-Based Hydrogels for Mechanoresponsive Energy-Harvesting Applications"
https://doi.org/doi:10.3390/gels11050307
https://pubmed.ncbi.nlm.nih.gov/40422327/
#Mechanical #Adhesion
"Sn-Doped Beta Zeolite with Rich Lewis Acidic Sites Enhances Lithium-Ion Dissociation and Transport in PEO-Based Solid Polymer Electrolytes"
https://doi.org/doi:10.1021/acsami.5c01991
https://pubmed.ncbi.nlm.nih.gov/40420418/
#Mechanical #Adhesion
"Microtubule polymerization generates microtentacles important in circulating tumor cell invasion"
https://arxiv.org/abs/2505.18301 #Physics.Med-Ph #Physics.Bio-Ph #Microtubule #Adhesion #Force
arXiv.orgMicrotubule polymerization generates microtentacles important in circulating tumor cell invasionCirculating tumor cells (CTCs) have crucial roles in the spread of tumors during metastasis. A decisive step is the extravasation of CTCs from the blood stream or lymph system, which depends on the ability of cells to attach to vessel walls. Recent work suggests that such adhesion is facilitated by microtubule (MT)-based membrane protrusions called microtentacles (McTNs). However, how McTNs facilitate such adhesion and how MTs can generate protrusions in CTCs remain unclear. By combining fluorescence recovery after photobleaching (FRAP) experiments and simulations we show that polymerization of MTs provides the main driving force for McTN formation, whereas the contribution of MTs sliding with respect to each other is minimal. Further, the forces exerted on the McTN tip result in curvature, as the MTs are anchored at the other end in the MT organizing center. When approaching vessel walls, McTN curvature is additionally influenced by the adhesion strength between the McTN and wall. Moreover, increasing McTN length, reducing its bending rigidity, or strengthening adhesion enhances the cell-wall contact area and, thus, promotes cell attachment to vessel walls. Our results demonstrate a link between the formation and function of McTNs, which may provide new insight into metastatic cancer diagnosis and therapy.
"A Computational Approach for Modeling Platelet Adhesion Dynamics on Thrombogenic Surfaces"
https://arxiv.org/abs/2505.18936 #Physics.Bio-Ph #Dynamics #Adhesion #Force
arXiv.orgA Computational Approach for Modeling Platelet Adhesion Dynamics on Thrombogenic SurfacesPlatelet adhesion and aggregation are essential for primary hemostasis, forming a clot that quickly stops initial bleeding. Despite this critical role, the dynamic interactions of platelet receptors with exposed collagen and von Willebrand factor (vWF) at the injury site and how these interactions influence thrombus formation under varying blood flow conditions are not fully understood. This study aimed to investigate the mechanisms of platelet adhesion and aggregation on collagen- or vWF-coated surfaces numerically. We combined the stochastic Bell's law with a deterministic elastic force featuring a time-dependent coefficient within the context of a dissipative particle dynamics (DPD) model to simulate thrombosis formation numerically. Our simulation results revealed that the numerically predicted platelet adhesion patterns closely matched experimental observations reported in the literature, demonstrating accurate replication of platelet behavior on collagen- and vWF-coated surfaces. Consequently, our deterministic/stochastic force model in DPD provides valuable insights into platelet adhesion dynamics under different flow conditions. These results contribute to a deeper understanding of platelet dynamics and potential therapeutic targets for managing hemostatic disorders.