Stable Adhesion Research Articles

Effect of phytic acid on dentinal collagen solubilization and its binding and debinding potentials to dentin

ObjectivesTo study phytic acid (IP6) effect on collagen solubilization by assessing hydroxyproline (HYP) release, evaluate its binding to demineralized (DD) and mineralized dentin (MD) and determine the effect of different media on debinding of IP6. MethodsDemineralized dentin beams were incubated in 1%, 2% or 3% IP6 and HYP release was evaluated at 1 or 3 weeks and compared to those obtained in untreated control or phosphoric acid (PA)-treated beams. DD or MD powder was treated with 1%, 2% or 3% IP6 and the decrease in IP6 amount was quantitated by ultraviolet–visible spectroscopy. IP6-treated samples were re-suspended in distilled water, ethanol, urea or sodium chloride and the amount of IP6 displaced was determined. ResultsAt 1 week, the control group and IP6 showed lower HYP release when compared to PA (P < 0.05). There was no difference among PA, IP6 and control at 3 weeks (P = 0.22). IP6 binding was concentration dependent. 1% IP6 had higher binding potential with MD compared to DD while 2% IP6 showed the opposite result (P<0.05). 3% IP6 had similar binding values between DD and MD (P = 0.53). The highest debinding in MD occurred with urea for 2%, 3% and 1% IP6 in descending manner. Within each concentration of IP6 in DD, the highest debinding effect was reported with ethanol. ConclusionsIP6 bound to DD and MD in a concentration-dependent manner. IP6 was debound from DD mostly by the action of ethanol, while in MD, urea caused the most displacement. Collagen solubilization of IP6-treated DD was comparable to untreated DD. Clinical significanceThese findings add to the potential use of IP6 as an alternative to PA for dentin etching which possibly results in long-term stability of resin-dentin adhesion.

Molecular docking study on europium nanoparticles and mussel adhesive protein for effective detection of latent fingerprints

Background: Reflecting on the difficulty of finding the evidence of latent fingerprints on wet and rough surfaces, scientists need to visualise those fingermarks without any background interference and stable adhesion of visualising material over the fingermark residues. Objective: To stabilize the interaction with the fingermarks, the synthesized nanoparticles were conjugated with a highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interact with fingerprint deposits. Material and Methods: Rare earth metal, europium oxide and nanoparticles were used as a visualisation material to get high contrast and reduced background interference-based fingerprints. To stabilise the interaction with the fingermarks, the synthesised nanoparticles were conjugated with highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interacts with fingerprint deposits. A molecular docking study was done using Auto-Dock to find the binding affinity between the metal nanoparticle and the protein. Further, the stability of the bioconjugated with fingerprint residues was analysed by protein-protein interaction study through patch dock and PDB Sum. Results: The docking analysis between europium and nanoparticles with MAP was found to be −8.77 kcal/mol and −47.49 kcal/mol respectively. Protein-protein interaction studies showed a highest affinity for dermcidin and keratin with a binding affinity of −16.76 kcal/mol and −24.76 kcal/mol respectively. Conclusions: The docking studies showed an efficient interaction between the synthesised molecules and the fingermark residues. Results of these interaction studies proved that this bio-conjugated complex can be explored for efficient visualisation of low intensified fingermarks.

A biodegradable bioinspired oil-coated adhesive film for enhanced wet adhesion

Bioinspired and biodegradable polymer-based adhesive films have attracted attention in the medical field because of their stable adhesion performance and ability to decompose in the body without additional surgical procedures. Among biodegradable materials, poly (glycerol sebacate) (PGS) can be applied to softenss-tuned microarchitecture-based adhesive films, because it has bioresorbable and residue-free characteristics. Herein, we presented a bioinspired oil-coated adhesive film fabricated using PGS, which can maintain adhesion on a wet surface by mimicking the toe pad and mucus of a frog. To implement frog-like adhesive architectures, the particular criteria under which PGS can be patterned were presented using simple models based on the degree of esterification and interfacial energy difference. Wet adhesion of our oil-coated film was achieved by replicating the frog-like hexagonal micro-channel and concave cup structures coated with vicious glycerol oil, resulting in a stable residue-free wet adhesion against diverse non-flat soft organ surfaces.

Stabilization of cell-cell adhesions prevents symmetry breaking and locks inpluripotency in 3D gastruloids.

3D embryonic stem cell (ESC) aggregates self-organize into embryo-like structures named gastruloids that recapitulate the axial organization of post-implantation embryos. Crucial in this process is the symmetry-breaking event that leads to the emergence of asymmetry and spatially ordered structures from homogeneous cell aggregates. Here, we show that budesonide, a glucocorticoid drug widely used to treat asthma, prevents ESC aggregates to break symmetry. Mechanistically, the effect of budesonide is glucocorticoid receptor independent. RNA sequencing and lineage fate analysis reveal that budesonide counteracts exit from pluripotency and modifies the expression of a large set of genes associated with cell migration, A-P axis formation, and WNT signaling. This correlates with reduced phenotypic and molecular cell heterogeneity, persistence of E-CADHERIN at the cell-cell interface, and cell aggregate compaction. Our findings reveal that cell-cell adhesion properties control symmetry breaking and cell fate transition in 3D gastruloids and suggest a potential adverse effect of budesonide on embryo development.

An Injectable Rapid‐Adhesion and Anti‐Swelling Adhesive Hydrogel for Hemostasis and Wound Sealing (Adv. Funct. Mater. 46/2022)

Injectable Anti-Swelling Adhesive Hydrogels In article number 2207741, Xiaoli Zhao, Haobo Pan, and co-workers develop an injectable anti-swelling adhesive hydrogel with rapid adhesion and volume stability in humid internal environment to achieve fast hemostasis and wound healing. Compared with swelling hydrogel bioadhesives, the hydrogel in this study avoids undesirable compression injury to the spinal cord and ensures the transmission of nerve signals when being applied in spinal surgery.

Epithelial coxsackievirus adenovirus receptor promotes house dust mite-induced lung inflammation

Airway inflammation and remodelling are important pathophysiologic features in asthma and other respiratory conditions. An intact epithelial cell layer is crucial to maintain lung homoeostasis, and this depends on intercellular adhesion, whilst damaged respiratory epithelium is the primary instigator of airway inflammation. The Coxsackievirus Adenovirus Receptor (CAR) is highly expressed in the epithelium where it modulates cell-cell adhesion stability and facilitates immune cell transepithelial migration. However, the contribution of CAR to lung inflammation remains unclear. Here we investigate the mechanistic contribution of CAR in mediating responses to the common aeroallergen, House Dust Mite (HDM). We demonstrate that administration of HDM in mice lacking CAR in the respiratory epithelium leads to loss of peri-bronchial inflammatory cell infiltration, fewer goblet-cells and decreased pro-inflammatory cytokine release. In vitro analysis in human lung epithelial cells confirms that loss of CAR leads to reduced HDM-dependent inflammatory cytokine release and neutrophil migration. Epithelial CAR depletion also promoted smooth muscle cell proliferation mediated by GSK3β and TGF-β, basal matrix production and airway hyperresponsiveness. Our data demonstrate that CAR coordinates lung inflammation through a dual function in leucocyte recruitment and tissue remodelling and may represent an important target for future therapeutic development in inflammatory lung diseases.

Chemical Treatment of Sn‐Containing Transparent Conducting Oxides for the Enhanced Adhesion and Thermal Stability of Electroplated Metals

AbstractA surface treatment process, named ReTreat, is presented, and is shown to enhance the adhesion of electroplated metals on Sn‐containing transparent conducting oxides (TCOs). The ReTreat process uses Zn powders, FeSO4 and glycine‐buffered aqueous solutions (pH 3 to 5) in order to regulate a controlled and uniform conversion of SnO2 surfaces to SnO, Sn metal, and FexSny alloys. These surface metallic and intermetallic layers selectively enrich the electroplating of metallic films (including Ni, Au, and Ag). Subsequently, the process has been used to fabricate thermally stable metal films on rigid FTO‐coated glass and flexible ITO‐coated PET substrates. Standardized testing confirms that the metallic coatings exhibit sufficient adhesion to the underlying TCO with high thermal stability and tolerance to flexural strain. A reaction mechanism for the heterogenous surface treatment is deduced from X‐ray diffraction, X‐ray photoelectron spectroscopy, and in situ transmittance measurements. These investigations show how the process parameters (e.g., Zn powders, FeSO4 concentration, pH, and TCO type) impact the reaction rate, morphology, and composition of the treated TCO surface. This report provides detailed insights necessary for the future implementation of this innovative surface treatment, which has the prospect to be a customary process for electroplating onto Sn‐containing TCOs.

Influence of particle shape on the interaction processes of coal particles and bubbles in saline solution

Understanding the role of coal particle shape in the flotation process is helpful in achieving a clean usage of coal slime flotation. In this investigation, the anthracite coal surface was modified using a chlorinated salt solution containing Na+, Ca2+, or Fe3+. Coal particles with four surface shapes were prepared: angular coal particles (ARPs), prismatic coal particles (PCPs), flat coal particles (FTPs), and spherical coal particles (SLPs). The ARPs were subdivided into five kinds of curvature: 3π/2, 21π/20, 7π/11, π/3, and π/10, and the PCPs were subdivided into five kinds of dihedral angles: 30°, 60°, 90°, 120°, and 150° according to the surface flatness of the ARPs and PCPs. Six ion concentrations, of 0, 5, 10, 20, 40, and 80 mmol/L, were examined. We tested the liquid film drainage time (LDT), maximum repulsive force (MRF), and maximum attractive force (MAF) between these coal particles and bubbles. The results show that at a constant solution concentration for a particular particle shape, the MRFs and LDTs increase in the order of Fe3+<Ca2+<Na+, and the MAFs decrease in the order of Fe3+>Ca2+>Na+. This indicates that Fe3+ enhances the adhesion probability and stability of anthracite particles and bubbles by the greatest extent, followed by Ca2+ and Na+. For a particular shape of coal particles, an increase in the ion concentration reduces the LDT and MRF and increases the MAF. When the curvature of the ARPs is 3π/2 and the dihedral angle of PCPs is 30°, the order of the LDTs of coal particles and bubbles is ARP < PCP < SLP < FTP. With a decrease in the curvature of ARPs and an increase in the dihedral angles of PCPs, their LDTs gradually approaches that of the FTP. The results for MRF and MAF are consistent with the LDT. Therefore, the ARPs with larger curvature and PCPs with smaller dihedral angles easily attach to air bubbles, and the decrease of the curvature and the increase of dihedral angles hindered the detachment. Adhesion and detachment experiments were conducted to confirm these results. The coal particles had a tendency to contact the bubbles with their available tips while sliding on the surfaces of bubbles to induce liquid film rupture. In addition, regardless of the coal particle shape, increasing ion concentration changes the detachment position of coal particles. These findings are consistent with the results of LDT, MRF, and MAF measurements. In this study, the role of coal particle shape in saline solution were systematically investigated, which provides a possible solution for the problems caused by the presence of ions in the flotation process using saline as the water source.

The surface modification of extruded polystyrene foams through UV curing and its stable adhesion to mortar

The hydrophobic surface of extruded polystyrene foams (XPSF) was modified by UV curable adhesives to enhance the interfacial bonding strength (BS) with mortar. The UV adhesive contained epoxy acrylate resin, acrylic acid and butyl acrylate (denoted as EAB). After EAB modification, the BS value in dry state (BS-D) increased from 0.050 MPa of unmodified XPSF with mortar to 0.210 MPa. Then, 3-aminopropyltriethoxysilane (APTES) was further introduced into EAB to form the water-resistant coatings (denoted as EABT) to enhance the BS value in wet state (BS-W). By optimizing the composition, the maximum BS-D and BS-W of 0.216 and 0.158 MPa in 7-day curing were obtained. The bonding mechanism illustrated that the modified XPSF was chemically bonded with mortar.

Stimulus-Responsive, Gelatin-Containing Supramolecular Nanofibers as Switchable 3D Microenvironments for Cells.

Polymer- and/or protein-based nanofibers that promote stable cell adhesion have drawn increasing attention as well-defined models of the extracellular matrix. In this study, we fabricated two classes of stimulus-responsive fibers containing gelatin and supramolecular crosslinks to emulate the dynamic cellular microenvironment in vivo. Gelatin enabled cells to adhere without additional surface functionalization, while supramolecular crosslinks allowed for the reversible switching of the Young’s modulus through changes in the concentration of guest molecules in culture media. The first class of nanofibers was prepared by coupling the host–guest inclusion complex to gelatin before electrospinning (pre-conjugation), while the second class of nanofibers was fabricated by coupling gelatin to polyacrylamide functionalized with host or guest moieties, followed by conjugation in the electrospinning solution (post-conjugation). In situ AFM nano-indentation demonstrated the reversible switching of the Young’s modulus between 2–3 kPa and 0.2–0.3 kPa under physiological conditions by adding/removing soluble guest molecules. As the concentration of additives does not affect cell viability, the supramolecular fibers established in this study are a promising candidate for various biomedical applications, such as standardized three-dimensional culture matrices for somatic cells and the regulation of stem cell differentiation.

Flexible, adhesive, strain‐sensitive, and skin‐matchable hydrogel strain sensors for human motion and handwritten signal monitoring

AbstractFlexible hydrogel strain sensors have made great progress in medical applications, human motion detection, and human‐machine interactions. However, the design of hydrogels to realize the synergistic responses of excellent mechanical properties, robust adhesion, and stable sensing is still a highly challenging task. Herein, we report a multifunctional hydrogel (PAMT hydrogel) by crosslinking acrylic acid (AA), 2‐methacryloyloxyethyl phosphorylcholine (MPC) and tannic acid (TA) to form a polymer network via a simple one‐pot free radical polymerization. Among them, the dynamic bonding with hydrogen bonding between PAA chains and TA significantly improved the stretch ability of the hydrogels (700%), and the abundant catechol groups on TA endowed the hydrogels with strong and stable adhesion properties (the adhesion strength to glass reached 248 N m−1). When applied to human skin, the hydrogel can be easily peeled off without leaving any residue. Furthermore, the strain sensor assembled using PAMT hydrogel could not only effectively detect the movement in different parts of the human body, but also be used for precise handwritten recognition and electric skin of silicone prosthetic hand. Due to the addition of MPC and TA, the conductive hydrogel has good biocompatibility and no harm to human body. Therefore, PAMT hydrogel has opened up a new vision for the development of intelligent detection and bionic intelligent robots.

Novel 3D Cu2O/N-CQD/ZIF-8 composite photocatalyst with Z-scheme heterojunction for the efficient photocatalytic reduction of Cr(Ⅵ)

ZIF-8 exhibits poor visible light response and rapid electron-hole recombination. To address these problems, we constructed an N-CQD/ZIF-8 framework by in-situ synthesis method, then prepared a novel Z-scheme heterostructure photocatalyst (Cu2O/N-CQD/ZIF-8) by reduction precipitation method for the efficient photocatalytic reduction of Cr(Ⅵ). Cu2O/N-CQD/ZIF-8 (with a 10% Cu2O loading) had a unique heterostructure and exhibited significantly improved performance for Cr(Ⅵ) photoreduction. This photocatalyst successfully reduced 98.99% of the Cr(Ⅵ) in a pH = 3 solution system, which was 6 times higher than that of ZIF-8. Meantime, due to its stable interfacial adhesion, the reduction efficiency of Cr(Ⅵ) by Cu2O/N-CQD/ZIF-8 still reached 97.13% after five cycles. Therefore, Cu2O/N-CQD/ZIF-8 exhibited superior photocatalytic activity and recyclability compared with unmodified ZIF-8. The charge transfer path of this Z-scheme heterojunction was verified by free radical trapping experiments and X-ray photoelectron spectroscopy. Moreover, a possible charge transfer mechanism was proposed. N-CQD provided a potential driving force for the construction of the internal Z-scheme charge transfer system. Moreover, the synergistic effect between Cu2O and ZIF-8 inhibited the rapid recombination of photogenerated electron-hole pairs. This work provides potential insights for the innovative design of high-performance photocatalysts based on metal-organic frameworks for the restoration of Cr(Ⅵ)-containing wastewater.

Low Surface Potential with Glycoconjugates Determines Insect Cell Adhesion at Room Temperature.

Cell-coupled field-effect transistor (FET) biosensors have attracted considerable attention because of their high sensitivity to biomolecules. The use of insect cells (Sf21) as a core sensor element is advantageous due to their stable adhesion to sensors at room temperature. Although visualization of the insect cell-substrate interface leads to logical amplification of signals, the spatiotemporal processes at the interfaces have not yet been elucidated. We quantitatively monitored the adhesion dynamics of Sf21 using interference reflection microscopy (IRM). Specific adhesion signatures with ring-like patches along the cellular periphery were detected. A combination of zeta potential measurements and lectin staining identified specific glycoconjugates with low electrostatic potentials. The ring-like structures were disrupted after cholesterol depletion, suggesting a raft domain along the cell periphery. Our results indicate dynamic and asymmetric cell adhesion is due to low electrostatic repulsion with fluidic sugar rafts. We envision the logical design of cell-sensor interfaces with an electrical model that accounts for actual adhesion interfaces.

Experimental investigation on the effects of a new anti-stripping additive on performance properties of asphalt and its mixtures

• A new compound anti-stripping additive called DMA-NSDD was developed. • The asphalt and its mixture performance was investigated by experiments. • A comparison was made of the performance of seven asphalts and their mixtures. • The performance of asphalt with DMA-NSDD and its mixtures was markedly improved. This study aims to investigate the effects of a new compound anti-stripping additive called DMA-NSDD, which comprised dopamine methacrylamide (DMA) that is a marine biomimetic material and nano-silicon dioxide dispersion (NSDD), on the performance properties of asphalt and its mixtures by experiments. The main steps of DMA synthesis were described. The test methods used in this study for asphalt and asphalt mixture performance were also introduced. The performance properties of asphalt with DMA-NSDD and its mixtures were investigated by comparing with those of virgin asphalt, styrene–butadienestyrene (SBS) modified asphalt, anti-stripping asphalts DMA, NSDD, LYKB™, and GLWS™, and their mixtures. Results showed that the marine biomimetic material DMA could be used in asphalt and its mixtures to increase their performance properties. Compared with SBS, DMA, NSDD, LYKB™, and GLWS™, the asphalt–aggregate adhesion and water stability of the asphalt mixtures with DMA-NSDD were the best and enhanced most significantly. The high- and low-temperature performance of the asphalt mixtures with DMA-NSDD was also notably improved, although it was second only to that of the SBS-modified asphalt mixtures. Overall, with DMA-NSDD, the performance properties of asphalt mixtures with granite aggregates improved more than those of asphalt mixtures with limestone aggregates.

Development and Control of a Bioinspired Robotic Remora for Hitchhiking

Remora, a bony fish, is well known for the remarkable hitchhiking behavior, by which it can transport itself over large distances without too much effort. In this article, a novel robotic remora with a stable adhesion system and its motion control methods are proposed for transferring the hitchhiking behavior to the engineered system. In terms of the mechatronic design, a robotic prototype with the uncoupled planar and vertical motion mechanisms is created to realize the precise and agile movement. Furthermore, a reliable adhesion system possessing low preload demand, considerable adhesive force ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim \text{250}\text{ N}$</tex-math></inline-formula> ), and reversible adhesion ability is developed, and then, the design principle of the adhesive disc is investigated. In the aspect of motion control, a mode-switch-based planar pose (position and orientation) control method and an antidisturbance depth control method are designed. The combination of these two controllers endows the robotic remora with the ability to precisely arrive at any position in a 3-D space, which paves the way for the hitchhiking task. Extensive experimental results are presented to support the performance benefits of the proposed robotic remora and control methods. Finally, the hitchhiking behavior is implemented successfully by robotic remora. To the best of our knowledge, this is the first engineered implementation of hitchhiking for a fin-actuated underwater robot. The results obtained will promote the design and control of the future underwater adhesion robot and offer valuable insights into the long-endurance robotic fish and mother–son multirobot system.

Synergy of Host–Guest and Cation−π Interactions for an Ultrastretchable, pH-Tunable, Surface-Adaptive, and Salt-Resistant Hydrogel Adhesive

The adhesion to wet, acidic, and saline biointerfaces with large deformation is important in the fields of wound dressing and motion monitoring but has proven to be extremely challenging. There is a need for a facile method to improve the stretchability and salt resistance simultaneously. Here, an ultrastretchable, pH-tunable, surface-adaptive, and salt-resistant hydrogel adhesive is reported. The hydrogel adhesive is prepared through cross-linking acrylamide with a supramolecular complex of poly(β-cyclodextrin) (PCD) and benzimidazole (BI). The dynamic association between PCD and BI causes an extra energy dissipation and improves the breaking strain to be larger than 4000%. The hydrogel exhibits stable adhesiveness to varieties of surfaces due to the multiple types of hydrogel–surface interactions, including ionic bond, π–π stacking, and hydrogen bond. Notably, the adhesive strength of the hydrogel gets significantly enhanced in an acidic environment and shows no attenuation in a saline environment. This is due to the unique adjacent cation−π structure of BI: the imidazole can be protonized upon acidification, and the phenyl group can repel water and enhance the ionic attraction with the substrates. The ultrastretchability, the stable adhesion on biointerfaces, and the salt resistance render the hydrogel a promising candidate for the surgical patch and motion sensors that serve in wet, acidic, and dynamic environments.

Study on laser cladding process and friction characteristics of friction pairs of copper-based powder metallurgy materials

To address the problems such as abnormal wear and the friction layer falling off caused by insufficient adhesion stability of clutch friction pairs formed by traditional sintering and pressing, the laser cladding process manufacturing method was used to prepare the cladding layer of the copper-based powder metallurgy friction materials by using Laserline LDF 6000–100 semiconductor laser, and the prepared friction pairs were tested and analyzed by SEM in this paper. The numerical model of the friction torque of the wet clutch was established, and the friction performance and wear tests were carried out using MM-3000 performance test machine. The friction characteristics of the wet clutch prepared by the laser cladding process were investigated under typical operating conditions. The results show that the accuracy of the numerical model is verified by the experiments; The friction layer prepared by laser cladding technology has compact structure, without obvious crack defects, and has good wear resistance. Compared with the traditional sintering and pressing technology, the wear rate of the friction pairs is reduced by 59.76%; The maximum slipping friction work under different engagement pressures increases with the increase of rotating speed; The friction torque can rapidly reach the maximum value after the clutch is fully engaged, and the equivalent friction coefficient also reaches the extreme value correspondingly at this time.

Evaluation of Viscoelastic Adhesion Strength and Stability of Composite Waterproofing Sheet Using Non-Hardening Viscoelastic Synthetic Polymer-Based Rubber Gel

Recently, a non-hardening type synthetic polymerized rubber gel (hereinafter referred to as NHV-SPRG) composite waterproofing sheet has been used on construction site as a new waterproofing technology. In this study, a test method is proposed in which a composite waterproof sheet is attached to an area of 150 mm in length and 100 mm in width on the mortar-based substrate specimen, and subsequently peeled off at 180 ° vertically to measure the “peel load (N)” at 10 points of 10 mm intervals (P1~P10, from 30 mm point to 120 mm point). Value obtained by dividing the average value of the measured peeling load by a width of 100 mm was defined as “viscoelastic adhesion strength (N/mm)”. The viscoelastic adhesive strength evaluated for the NHV-SPRG composite waterproof sheet of 4 types (VG-1, VG-2, VG-3, VG-4) was an average of 1.99 N/mm. To examine the effectiveness of the viscoelastic adhesive strength, the adhesion stability was evaluated based on the peel load’s coefficient of variation, grade of the linear regression line of the peel load, and peel load percent relative range in peel load for each section of the composite waterproofing layer. As a result, the VG-2 type was measured to have the highest viscoelastic adhesive strength, but the VG-1 type was confirmed to have the highest adhesive stability. Considering these results, it is judged that even a product with high adhesion can have varying stability in terms of performance that can affect construction precision. The test method and performance standard value for the viscoelastic adhesion strength proposed as an evaluation index through this study are expected to be used as a quality control standard to secure the on-site adhesion stability of the NHV-SPRG composite waterproof sheet.

The emergence of spontaneous coordinated epithelial rotation on cylindrical curved surfaces.

Three-dimensional collective epithelial rotation around a given axis represents a coordinated cellular movement driving tissue morphogenesis and transformation. Questions regarding these behaviors and their relationship with substrate curvatures are intimately linked to spontaneous active matter processes and to vital morphogenetic and embryonic processes. Here, using interdisciplinary approaches, we study the dynamics of epithelial layers lining different cylindrical surfaces. We observe large-scale, persistent, and circumferential rotation in both concavely and convexly curved cylindrical tissues. While epithelia of inverse curvature show an orthogonal switch in actomyosin network orientation and opposite apicobasal polarities, their rotational movements emerge and vary similarly within a common curvature window. We further reveal that this persisting rotation requires stable cell-cell adhesion and Rac-1–dependent cell polarity. Using an active polar gel model, we unveil the different relationships of collective cell polarity and actin alignment with curvatures, which lead to coordinated rotational behavior despite the inverted curvature and cytoskeleton order.

Injectable adhesive self-healing biocompatible hydrogel for haemostasis, wound healing, and postoperative tissue adhesion prevention in nephron-sparing surgery

Nephron-sparing surgery is a well-established treatment in patients with T1a renal cell carcinoma; however, the complex suturing process prolongs warm ischaemia time, affects the preservation of normal renal parenchymal function, and causes avoidable postoperative tissue adhesion complications, including chronic abdominal pain, intestinal obstruction, and female infertility. Hence, the design of multifunctional biomaterials with haemostasis, postoperative wound management, and postoperative tissue adhesion prevention properties for nephron-sparing surgeries is urgently needed. In this study, a series of injectable adhesive multifunctional biocompatible hydrogels were designed based on the free-radical polymerisation of monomers acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG), and the ionic coordination between Ca2+ and the abundant carboxyl groups in AA and NAG. AA/NAG/Ca (AA, NAG, and Ca refer to acryloyl-6-aminocaproic acid, N-acryloyl 2-glycine and calcium chloride, respectively) hydrogel exhibited good mechanical properties, swelling and adhesion properties, flexibility, in vitro blood-clotting ability, and cytocompatibility. In vivo experiments on liver injury models and rat/rabbit nephron-sparing surgery models elucidated that the AA/NAG/Ca hydrogel had haemostasis performance and wound healing properties that led to short bleeding time, reduced bleeding volume, and well-organised nephron structures. An abdomen-caecum adhesion model indicated that the AA/NAG/Ca hydrogel showed excellent anti-adhesion properties. In summary, this multifunctional hydrogel exhibited potential for improving haemostasis and wound management in nephron-sparing surgeries, showing potential for clinical application. Statement of significanceExtended warm ischemia time during nephron sparing surgery negatively affected postoperative renal function due to the need for hemostasis at the wound with abundant blood supply, and postoperative wound healing and additional adhesions caused by the surgical procedure deserve attention. Based on the efficient and stable adhesion properties of hydrogels and the ability to promote wound healing. Herein, a series of adhesive self-healing biocompatible hydrogels were prepared based on free-radical polymerization of acryloyl-6-aminocaproic acid (AA) and N-acryloyl 2-glycine (NAG) and the ionic coordination between Ca2+ with the abundant carboxyl groups in AA and NAG. AA/NAG/Ca hydrogel showed hemostasis property in nephron sparing surgery model, promote kidney wound healing, and could perform anti-postoperative adhesion efficacy in an abdomen-caecum adhesion model.