Search

Focused ultrasound has experimentally been found to enhance the diffusion of nanoparticles; our aim with this work is to study this effect closer using both experiments and non-equilibrium molecular dynamics. Measurements from single particle tracking of 40 nm polystyrene nanoparticles in an agarose hydrogel with and without focused ultrasound are presented and compared with a previous experimental study using 100 nm polystyrene nanoparticles. In both cases, we observed an increase in the mean square displacement during focused ultrasound treatment. We developed a coarse-grained non-equilibrium molecular dynamics model with an implicit solvent to investigate the increase in the mean square displacement and its frequency and amplitude dependencies. This model consists of polymer fibers and two sizes of nanoparticles, and the effect of the focused ultrasound was modeled as an external oscillating force field. A comparison between the simulation and experimental results shows similar mean square displacement trends, suggesting that the particle velocity is a significant contributor to the observed ultrasound-enhanced mean square displacement. The resulting diffusion coefficients from the model are compared to the diffusion equation for a two-time continuous time random walk. The model is found to have the same frequency dependency. At lower particle velocity amplitude values, the model has a quadratic relation with the particle velocity amplitude as described by the two-time continuous time random walk derived diffusion equation, but at higher amplitudes, the model deviates, and its diffusion coefficient reaches the non-hindered diffusion coefficient. This observation suggests that at higher ultrasound intensities in hydrogels, the non-hindered diffusion coefficient can be used. [ABSTRACT FROM AUTHOR]

Tracer diffusion in polymer networks and hydrogels is relevant in biology and technology, while it also constitutes an interesting model process for the dynamics of molecules in fluctuating, heterogeneous soft matter. Here, we systematically study the time-dependent dynamics and (non-Markovian) memory effects of tracers in polymer networks based on (Markovian) implicit-solvent Langevin simulations. In particular, we consider spherical tracer solutes at high dilution in regular, tetrafunctional bead-spring polymer networks and control the tracer–network Lennard-Jones (LJ) interactions and the polymer density. Based on the analysis of the memory (friction) kernels, we recover the expected long-time transport coefficients and demonstrate how the short-time tracer dynamics, polymer fluctuations, and the viscoelastic response are interlinked. Furthermore, we fit the characteristic memory modes of the tracers with damped harmonic oscillations and identify LJ contributions, bond vibrations, and slow network relaxations. Tuned by the LJ interaction parameter, these modes enter the kernel with an approximately linear to quadratic scaling, which we incorporate into a reduced functional form for convenient tracer memory interpolation and extrapolation. This eventually leads to highly efficient simulations utilizing the generalized Langevin equation, in which the polymer network acts as an additional thermal bath with a tunable intensity. [ABSTRACT FROM AUTHOR]

The work demonstrates, for the first time, thermo-responsive, water-insoluble, hydrogel-based, nano-fibrous filter media comprised of copolymers of N-isopropylacrylamide (NIPAM) and methyl methacrylate formed by electrospinning. Moreover, a comprehensive novel physical explanation of all aspects responsible for the physical mechanisms resulting in the thermo-responsive regulation of the water flow rate and an enhanced interception of nanoparticles by such filter membranes is given. They are the wettable-non-wettable transition, pore, and fiber-size changes, as well as a diminishing filter thickness at the lower critical solution temperature (LCST) of the copolymers developed here, which interplay with a significant reduction in the water viscosity with temperature. Poly(N-isopropylacrylamide) (PNIPAM) hydrogel is an attractive material because of its thermo-responsive properties. Its wettability changes with water temperature. This characteristic holds great promise for the development of advanced filter media and related responsive materials. In this study, PNIPAM hydrogels were designed and transformed into filter membranes for applications in water filtration in biomedical and other related systems. These thermo-responsive filter membranes offer the potential for enhanced filtration efficiency, selectivity, and the overall system performance. Here, two different procedures were adopted to form water-insoluble thermo-responsive filter media based on PNIPAM hydrogels. The PNIPAM-based hydrogels were electrospun, resulting in the formation of thermo-responsive water-insoluble nanofiber membranes. These membranes underwent a series of comprehensive experiments to assess their performance and characteristics, including mass loss, water droplets for the wettability assessment, filtration tests, shrinkage measurements, and microscopic observations. These diverse experiments yield a full understanding of the PNIPAM-based nanofiber membranes' properties and their potential applications. [ABSTRACT FROM AUTHOR]

The network structure within polymers significantly influences their mechanical properties, including their strength, toughness, and fatigue resistance. All-atom molecular dynamics (AAMD) simulations offer a method to investigate the energy dissipation mechanism within polymers during deformation and fracture; Such an approach is, however, computationally inefficient when used to analyze polymers with complex network structures, such as the common chemically double-networked hydrogels. Alternatively, coarse-grained molecular dynamics (CGMD) models, which reduce the computational degrees of freedom by concentrating a set of adjacent atoms into a coarse-grained bead, can be employed. In CGMD simulations, a coarse-grained force field (CGFF) is a critical factor affecting the simulation accuracy. In this paper, we proposed a data-based method for predicting the CGFF parameters to improve the simulation efficiency of complex cross-linked network in polymers. Here, we utilized a typical chemically double-networked hydrogel as an example. An artificial neural network was selected, and it was trained with the tensile stress–strain data from the CGMD simulations using different CGFF parameters. The CGMD simulations using the predicted CGFF parameters show good agreement with the AAMD simulations and are almost fifty times faster. The data-inspired CGMD model presented here broadens the applicability of molecular dynamics simulations to cross-linked polymers and has the potential to provide insights that will aid the design of polymers with desirable mechanical properties. [ABSTRACT FROM AUTHOR]

Dehydration has been a key limiting factor for the operation of conductive hydrogels in practical application. Here, we report self-healable ionic skins that can self-regulate their internal moisture level by capturing extenral moistures via hygroscopic ion-coordinated polymer backbones through antipolyelectrolyte effect. Results show the ionic skin can maintain its mechanical and electrical functions over 16 months in the ambient environment with high stretchability (fracture stretch ∼2216 %) and conductivity (23.5 mS/cm). The moisture self-regulating capability is further demonstrated by repeated exposures to harsh environments such as 200°C heating, freezing, and vacuum drying with recovered conductivity and stretchability. Their reversible ionic and hydrogen bonds also enable self-healing feature as a sample with the fully cut-through damage can restore its conductivity after 24 h at 40 % relative humidity. Utilizing the ionic skin as a building block, self-healing flexible piezoelecret sensors have been constructed to monitor physiological signals. Together with a facile transfer-printing process, a self-powered sensing system with a self-healable supercapacitor and humidity sensor has been successfully demonstrated. These results illustrate broad-ranging possibilities for the ionic skins in applications such as energy storage, wearable sensors, and human-machine interfaces.

Osteoarthritis is characterized by enzymatic breakdown of the articular cartilage via the disruption of chondrocyte homeostasis, ultimately resulting in the destruction of the articular surface. Decades of research have highlighted the importance of inflammation in osteoarthritis progression, with inflammatory cytokines shifting resident chondrocytes into a pro-catabolic state. Inflammation can result in poor outcomes for cells implanted for cartilage regeneration. Therefore, a method to promote the growth of new cartilage and protect the implanted cells from the pro-inflammatory cytokines found in the joint space is required. In this study, we fabricate two gel types: polymer network hydrogels composed of chondroitin sulfate and hyaluronic acid, glycosaminoglycans (GAGs) known for their anti-inflammatory and prochondrogenic activity, and interpenetrating networks of GAGs and collagen I. Compared to a collagen-only hydrogel, which does not provide an anti-inflammatory stimulus, chondrocytes in GAG hydrogels result in reduced production of pro-inflammatory cytokines and enzymes as well as preservation of collagen II and aggrecan expression. Overall, GAG-based hydrogels have the potential to promote cartilage regeneration under pro-inflammatory conditions. Further, the data have implications for the use of GAGs to generally support tissue engineering in pro-inflammatory environments.

Pancreatic ductal adenocarcinoma (PDAC) accounts for about 90% of all pancreatic cancer cases. Five-year survival rates have remained below 12% since the 1970s, in part due to the difficulty in detection prior to metastasis (migration and invasion into neighboring organs and glands). Mechanical memory is a concept that has emerged over the past decade that may provide a path toward understanding how invading PDAC cells "remember" the mechanical properties of their diseased ("stiff", elastic modulus, E ≈ 10 kPa) microenvironment even while invading a healthy ("soft", E ≈ 1 kPa) microenvironment. Here, we investigated the role of mechanical priming by culturing a dilute suspension of PDAC (FG) cells within a 3D, rheologically tunable microgel platform from hydrogels with tunable mechanical properties. We conducted a suite of acute (short-term) priming studies where we cultured PDAC cells in either a soft (E ≈ 1 kPa) or stiff (E ≈ 10 kPa) environment for 6 h, then removed and placed them into a new soft or stiff 3D environment for another 18 h. Following these steps, we conducted RNA-seq analyses to quantify gene expression. Initial priming in the 3D culture showed persistent gene expression for the duration of the study, regardless of the subsequent environments (stiff or soft). Stiff 3D culture was associated with the downregulation of tumor suppressors (LATS1, BCAR3, CDKN2C), as well as the upregulation of cancer-associated genes (RAC3). Immunofluorescence staining (BCAR3, RAC3) further supported the persistence of this cellular response, with BCAR3 upregulated in soft culture and RAC3 upregulated in stiff-primed culture. Stiff-primed genes were stratified against patient data found in The Cancer Genome Atlas (TCGA). Upregulated genes in stiff-primed 3D culture were associated with decreased survival in patient data, suggesting a link between patient survival and mechanical priming.

Macrophages are innate immune cells that interact with complex extracellular matrix environments, which have varied stiffness, composition, and structure, and such interactions can lead to the modulation of cellular activity. Collagen is often used in the culture of immune cells, but the effects of substrate functionalization conditions are not typically considered. Here, we show that the solvent system used to attach collagen onto a hydrogel surface affects its surface distribution and organization, and this can modulate the responses of macrophages subsequently cultured on these surfaces in terms of their inflammatory activation and expression of adhesion and mechanosensitive molecules. Collagen was solubilized in either acetic acid (Col-AA) or N-(2-hydroxyethyl)piperazine-N'-ethanesulfonic acid (HEPES) (Col-HEP) solutions and conjugated onto soft and stiff polyacrylamide (PA) hydrogel surfaces. Bone marrow-derived macrophages cultured under standard conditions (pH 7.4) on the Col-HEP-derived surfaces exhibited stiffness-dependent inflammatory activation; in contrast, the macrophages cultured on Col-AA-derived surfaces expressed high levels of inflammatory cytokines and genes, irrespective of the hydrogel stiffness. Among the collagen receptors that were examined, leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) was the most highly expressed, and knockdown of the Lair-1 gene enhanced the secretion of inflammatory cytokines. We found that the collagen distribution was more homogeneous on Col-AA surfaces but formed aggregates on Col-HEP surfaces. The macrophages cultured on Col-AA PA hydrogels were more evenly spread, expressed higher levels of vinculin, and exerted higher traction forces compared to those of cells on Col-HEP. These macrophages on Col-AA also had higher nuclear-to-cytoplasmic ratios of yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), key molecules that control inflammation and sense substrate stiffness. Our results highlight that seemingly slight variations in substrate deposition for immunobiology studies can alter critical immune responses, and this is important to elucidate in the broader context of immunomodulatory biomaterial design.

PURPOSE: Radiation therapy (RT) plays an important role in the treatment of glioblastoma multiforme (GBM). However, inherent intrinsic resistance of tumors to radiation, coupled with the need to consider the tolerance of normal tissues and the potential effects on neurocognitive function, impose constraints on the amount of RT that can be safely delivered. A strategy for augmenting the effectiveness of RT involves the utilization of radiation sensitizers (RS). Directly implanting RS-loaded fibrin glue (FG) into the tumor resection cavity would by-pass the blood brain barrier, potentially enhancing the impact of RT on tumor recurrence. This study investigated the ability of FG to incorporate and release, in non-degraded form, the radiation sensitizers 5-Fluorouracil (5FU) and Motexafin gadolinium (MGd). METHODS: FG layers were created in a 24-well plate by combining thrombin, fibrinogen, and 5FU or MGd. Supernatants from these layers were collected at various intervals and added to F98 glioma spheroid cultures in 96-well plates. Radiation was applied either before or after RS application as single or fractionated dosages. Spheroid growth was monitored for 14 days. RESULTS: Combined treatment of FG-released 5FU and RT significantly inhibited spheroid growth compared to RS or RT as a single treatment. As a free drug, MGd demonstrated its efficacy in reducing spheroid volume, but had diminished potency as a released RS. Fractionated radiation was more effective than single dose radiation. CONCLUSION: Non-degraded RS was released from the FG for up to 72 h. FG-released 5FU greatly increased the efficacy of radiation therapy.

The presence of gradient softer outer layers, commonly observed in biological systems (such as cartilage and ocular tissues), as well as synthetic crosslinked hydrogels, profoundly influences their interactions with opposing surfaces. Our prior research demonstrated that gradient-stiffness hydrogel layers, characterized by increasing elasticity with depth, control contact mechanics, particularly in proximity to the layer thickness. We postulate that the distribution of polymers within these gradient layers imparts extraordinary stretch and adhesion characteristics due to network adaptability and stress-induced reorganization. To investigate this phenomenon, we utilized Atomic Force Microscopy nanoindentation to assess the depth-dependent adhesion behavior of polyacrylamide hydrogels with varying gradient layer thicknesses. Two gradient layer thicknesses were achieved by employing different molding materials: glass and polyoxymethylene (POM). Glass-molded hydrogels exhibited a thinner gradient layer alongside a stiffer bulk layer compared to their POM-molded counterparts. In indentation experiments, the POM-molded hydrogel had larger adhesion compared to glass-molded hydrogel. We find that indenting within the gradient layer engenders increased load-unload hysteresis due to heightened fluid transport in the sparse outer polymer network. Consequently, this led to augmented adhesion and work of separation at shallow depths. We suggest that the prominent stretching capability of the sparse outer polymer network during probe retraction contributes to enhanced adhesion. The Maugis–Dugdale adhesive model only fits well to indentations on the thin layer or indentations which engage significantly with the bulk. These results facilitate a comprehensive characterization of adhesion mechanics in gradient-stiffness hydrogels, which could foster their application across emerging contexts in health science and environmental domains. [ABSTRACT FROM AUTHOR]

Stretching or compressing hydrogels creates anisotropic environments that lead to motionally averaged alignment of embedded guest quadrupolar nuclear spins such as 23Na+. These distorted hydrogels can elicit a residual quadrupolar coupling that gives an oscillation in the trajectories of single quantum coherences (SQCs) as a function of the evolution time during a spin-echo experiment. We present solutions to equations of motion derived with a Liouvillian superoperator approach, which encompass the coherent quadrupolar interaction in conjunction with relaxation, to give a full analytical description of the evolution trajectories of rank-1 ( T ^ 1 ± 1 ), rank-2 ( T ^ 2 ± 1 ), and rank-3 ( T ^ 3 ± 1 ) SQCs. We performed simultaneous numerical fitting of the experimental 23Na nuclear magnetic resonance (NMR) spectra and rank-2 ( T ^ 2 ± 1 ) and rank-3 ( T ^ 3 ± 1 ) SQC evolution trajectories measured in double and triple quantum filtered experiments, respectively. We estimated values of the quadrupolar coupling constant CQ, rotational correlation time τC, and 3 × 3 Saupe order matrix. We performed simultaneous fitting of the analytical expressions to the experimental data to estimate values of the quadrupolar coupling frequency ωQ/2π, residual quadrupolar coupling ω Q / 2 π , and corresponding spherical order parameter S 0 * , which showed a linear dependence on the extent of uniform hydrogel stretching and compression. The analytical expressions were completely concordant with the numerical approach. The insights gained here can be extended to more complicated (biological) systems such as 23Na+ bound to proteins or located inside and outside living cells in high-field NMR experiments and, by extension, to the anisotropic environments found in vivo with 23Na magnetic resonance imaging. [ABSTRACT FROM AUTHOR]

Alginate hydrogels possess properties analogous to those of the extracellular matrix (ECM). Thus, their mechanical behavior approximates soft tissue, which makes them desirable for the production of tissue-equivalent soft deformable structures. This study aims to determine the synthesis-structure-property relationship for alginate hydrogel with the Young’s modulus in the range of 10°~101 kPa, mimicking to that of human lung tissue. Hydrogels, a 3D polymer network embedded in a water-rich environment. Homogeneous alginate hydrogels are synthesized by a direct mixture of sodium alginate and CaCO3, followed by the addition of D-glucono-δ-lactone (GDL) to initiate in-situ Ca2+ release and gelation. The influence of alginate concentration and molar ratio of the constituent calcium ion to carboxyl group from alginate monomer are evaluated while the Young’s modulus of the hydrogel is carefully controlled within the desired range. FTIR and SEM are used to characterize the influence of synthesis parameters at the molecular and microstructure levels. Tension and compression testing are performed to determine the Young’s modulus of the material. Empirical relations are established between synthesis parameters and the mechanical property. The result of the study will be subsequently used to guide the additive manufacturing of soft deformable structures based on alginate hydrogels. [ABSTRACT FROM AUTHOR]

A composite gel adsorbent was formed by simply mixing a polymer hydrogelator and an adsorbent material, activated carbon. The composite materials retained the thixotropic properties, and activated carbon was uniformly dispersed in the composite gel. Since functional particles such as activated carbon show the ability to subdivide and strengthen the fibre structure of this hydrogel, this hydrogel may be able to form a functional gel material composited with other functional particles. In practice, the composite gel could adsorb dyes, owing to the presence of activated carbon, without damaging the gel state in brine. [ABSTRACT FROM AUTHOR]

In this paper, nitrogen-doped carbon quantum dots (N-CQDs) were prepared by using citric acid as a carbon source and ethylenediamine as a nitrogen source. Then, N-CQDs were added into a deep eutectic solvent (DES) synthesized from acrylamide (AM), urea (U), and choline chloride (ChCl). The N-CQDs/P(AM-U-ChCl) composite hydrogels were prepared by light polymerization. The chemical composition and microstructure of N-CQDs/P(AM-U-ChCl) composite hydrogels were characterized in detail using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). This article further explored the influence of the content of N-CQDs on the mechanical properties, adsorption properties, and detection performance of the composite hydrogel. The results showed that the composite hydrogels exhibited the best mechanical properties when N-CQDs' content was 0.3 wt%. The adsorption performance of N-CQDs/P(AM-U-ChCl) composite hydrogels for Fe3+ was significantly enhanced due to the carboxyl groups contained in N-CQDs. In detecting tert-butylhydroquinone (TBHQ), the composite hydrogel showed a good linear correlation in the concentration range of 0–200 mg L−1, and the detection limit of TBHQ reached 0.849 mg L−1. This study provides a new idea for preparing composite hydrogel materials with excellent mechanical properties and functionality. Also, it demonstrates their potential application value in heavy metal ion adsorption and organic molecule detection. [ABSTRACT FROM AUTHOR]

In order to alleviate the enormous pressure that waste bagasse puts on the environment, BGO was prepared from waste bagasse. With Ca2+ crosslinked SA as the first network and BGO as the heterogeneous nucleus for the second network, the PVA/SA/BGO double-network hydrogel spheres were constructed with the help of freeze-thaw method. The structure, morphology and adsorption properties of the PVA/SA/BGO double-network hydrogel for the organic dye crystalline violet (CV) were investigated. The results show that the obtained BGO has a lamellar structure and abundant oxygen-containing groups. The maximum adsorption amount of PVA/SA/BGO double-network hydrogel toward CV is 460.21 mg ⋅ g-1, and the adsorption process is in accordance with the Langmuir adsorption model and the pseudo-second-order kinetics model. [ABSTRACT FROM AUTHOR]

Eukaryotic cells show an astounding ability to remodel their shape and cytoskeleton and to migrate through pores and constrictions smaller than their nuclear diameter. However, the relation of nuclear deformation and migration dynamics in confinement remains unclear. Here, we study the mechanics and dynamics of mesenchymal cancer cell nuclei transitioning through three-dimensional compliant hydrogel channels. We find a biphasic dependence of migration speed and transition frequency on channel width, peaking at widths comparable to the nuclear diameter. Using confocal imaging and hydrogel bead displacement, we determine nuclear deformations and corresponding forces during confined migration. The nucleus deforms reversibly with a reduction in volume during confinement. With decreasing channel width, the nuclear shape during transmigration changes biphasically, concomitant with the transitioning dynamics. Our proposed physical model explains the observed nuclear shapes and transitioning dynamics in terms of the cytoskeletal force generation adapting from purely pullingbased to a combined pulling-and pushing-based mechanism with increasing nuclear confinement. [ABSTRACT FROM AUTHOR]

This review highlights recent advancements in the synthesis, processing, properties, and applications of 2D‐material integrated hydrogels, with a focus on their performance in bone‐related applications. Various synthesis methods and types of 2D nanomaterials, including graphene, graphene oxide, transition metal dichalcogenides, black phosphorus, and MXene are discussed, along with strategies for their incorporation into hydrogel matrices. These composite hydrogels exhibit tunable mechanical properties, high surface area, strong near‐infrared (NIR) photon absorption and controlled release capabilities, making them suitable for a range of regeneration and therapeutic applications. In cancer therapy, 2D‐material‐based hydrogels show promise for photothermal and photodynamic therapies, and drug delivery (chemotherapy). The photothermal properties of these materials enable selective tumor ablation upon NIR irradiation, while their high drug‐loading capacity facilitates targeted and controlled release of chemotherapeutic agents. Additionally, 2D‐materials ‐infused hydrogels exhibit potent antibacterial activity, making them effective against multidrug‐resistant infections and disruption of biofilm generated on implant surface. Moreover, their synergistic therapy approach combines multiple treatment modalities such as photothermal, chemo, and immunotherapy to enhance therapeutic outcomes. In bio‐imaging, these materials serve as versatile contrast agents and imaging probes, enabling their real‐time monitoring during tumor imaging. Furthermore, in bone regeneration, most 2D‐materials incorporated hydrogels promote osteogenesis and tissue regeneration, offering potential solutions for bone defects repair. Overall, the integration of 2D materials into hydrogels presents a promising platform for developing multifunctional theragenerative biomaterials. [ABSTRACT FROM AUTHOR]

Natural cartilage exhibits superior lubricity as well as an ultra‐long service lifetime, which is related to its surface hydration, load‐bearing, and deformation recovery feature. Until now, it is of great challenge to develop reliable cartilage lubricating materials or coatings with persistent robustness. Inspired by the unique biochemical structure and mechanics of natural cartilage, the study reports a novel cartilage‐hydrogel composed of top composite lubrication layer and bottom mechanical load‐bearing layer, by covalently manufacturing thick polyelectrolyte brush phase through sub‐surface of tough hydrogel matrix with multi‐level crystallization phase. Due to multiple network dissipation mechanisms of matrix, this hydrogel can achieve a high compression modulus of 11.8 MPa, a reversible creep recovery (creep strain: ≈2%), along with excellent anti‐swelling feature in physiological medium (v/v0 < 5%). Using low‐viscosity PBS as lubricant, this hydrogel demonstrates persistent lubricity (average COF: ≈0.027) under a high contact pressure of 2.06 MPa with encountering 100k reciprocating sliding cycles, negligible wear and a deformation recovery of collapse pit in testing area. The extraordinary lubrication performance of this hydrogel is comparable to but beyond the natural animal cartilage, and can be used as compliant coating for implantable articular material of UHMWPE to present, offering more robust lubricity than current commercial system. [ABSTRACT FROM AUTHOR]

A temperature/pH dual‐sensitive hydrogel was prepared through simple solution radical polymerization. A novel temperature/pH dual‐sensitive terpolymerized semi‐interpenetrating network, P(NIPAAm‐co‐AA‐co‐HEAA)/SA hydrogel, was synthesized using interpenetrating network technology (IPN) with sodium alginate (SA) as the raw material. The temperature‐sensitive monomer N‐isopropylacrylamide (NIPAAm), the pH‐sensitive monomer acrylic acid (AA), and the hydrophilic monomer N‐hydroxyethylacrylamide (HEAA) were incorporated into the structure. The structure and morphology of the hydrogels were investigated using FTIR, TGA and SEM. Additionally, the swelling properties, as well as temperature and pH sensitivity, were examined. The results showed that the content of HEAA and SA influenced the swelling properties of the gels. The gels exhibited distinct swelling behaviors at different temperatures and pH levels, demonstrating remarkable temperature and pH sensitivity. Moreover, it shows rapid response speed and efficient recovery, making them suitable for use as anticancer drug carriers that meet specific requirements. [ABSTRACT FROM AUTHOR]

Trees grow by coupling the transpiration‐induced nutrient absorption from external sources and photosynthesis‐based nutrient integration. Inspired by this manner, we designed a class of polyion complex (PIC) hydrogels containing isolated liquid‐filled voids for growing texture surfaces. The isolated liquid‐filled voids were created via irreversible matrix reconfiguration in a deswelling‐swelling process. During transpiration, these voids reversibly collapse to generate negative pressures within the matrices to extract polymerizable compounds from external sources and deliver them to the surface of the samples for photopolymerization. This growth process is spatial‐controllable and can be applied to fabricate complex patterns consisting of different compositions, suggesting a new strategy for making texture surfaces. [ABSTRACT FROM AUTHOR]

Infectious bone defects are one of the thorny problems faced by orthopedists. Developing prosthetic materials with antimicrobial osteogenic features is a key solution. Biodegradable Polyacrylic acid (PAA)-based hydrogels have gained attention for their exceptional qualities. However, the influence of zinc ions on PAA-based mineralized hydrogels remains understudied. In this paper, Poly (acrylic acid)-calcium-zinc (PA-CZ) biomineralized hydrogel was prepared through ionic cross-linking and biomineralization. In vitro bacterial and cell tests demonstrated the hydrogel's exceptional biocompatibility, antibacterial, and osteogenic traits, along with good mechanical strength. The PA-CZ mineralized hydrogel lays the foundation for developing orthopedic implants with antimicrobial osteogenic features and offers a promising approach for treating infected bone defects. [ABSTRACT FROM AUTHOR]

Developing sustainable and effective treatments for chronic venous insufficiency (CVI) is crucial. In this study, we propose an innovative restorative approach utilizing hydrogels derived from the decellularized extracellular matrix (dECM) of cadaveric vascular tissues, adipose-derived stem cells (ADSCs), and gold nanoparticles (AuNPs). This therapeutic method leverages waste valorization by repurposing discarded cadaveric tissues from slaughterhouse livestock. The dECM hydrogels, enriched with ADSCs and AuNPs, offer a biocompatible scaffold that supports cellular differentiation and vascular integrity. Our approach addresses the limitations of current allo-, auto-, and xenograft methods by enhancing integration and functionality while potentially reducing costs through sustainable practices. This study explores functionalized hydrogel formulation solely generated from agri-food waste, gelation mechanisms, and preliminary cost-effectiveness, presenting a promising new avenue for treating early-stage varicose veins that can ultimately be translated to human models using discarded tissues. [ABSTRACT FROM AUTHOR]

Gallium ions have a special action mechanism that interferes bacterial iron metabolism, thereby possessing great potential for the treatment of bacterial infections. In this work, gallium ions‐cross‐linked konjac glucomannan/polyacrylamide (KGM/PAM/Ga3+) hydrogels are successfully constructed with satisfactory swelling ability, appropriate mechanical properties and adjustable degradation performance. Ga ions as a kind of cross‐linking agent can enhance the stability, and more importantly, improve the bactericidal ability of hydrogel, thus forming novel functional KGM/PAM/Ga3+ hydrogels for treating wounds. After the evaluation of antibacterial activity and biocompatibility, KGM/PAM/Ga3+ hydrogels can effectively inhibit the proliferation of bacteria through the gradual and sustainable release of Ga ions from the hydrogel with negligible cytotoxicity and good blood compatibility. Furthermore, they possess exceptional self‐healing behavior, and can be readily adapted to varying degrees of bending, which matches skin wound dressing application. Finally, the results of wound healing performance and histological evaluation demonstrate that KGM/PAM/Ga3+ hydrogels can efficiently accelerate infected wound healing and facilitate the regeneration of skin tissues. [ABSTRACT FROM AUTHOR]

Gastric ulcers accompanied by acute or chronic bleeding represent a significant risk of fatality. However, the development of effective strategies for achieving rapid hemostasis and wound healing in gastric ulcer bleeding represents a formidable challenge. To address this challenge, thrombin‐derived C‐terminal peptide (TCP‐25) is employed as a targeted agent, and it is incorporated into two novel injectable and biocompatible carboxymethyl chitosan (CMCs) hydrogels via Schiff's base reaction. The TCP‐25 peptide hydrogels display optimal adaptability within the distinctive gastrointestinal microenvironment, demonstrating a balance of acid resistance and degradation, along with controlled release and bioactivity, and good bio‐adhesive properties. Both in vitro and in vivo reveal that the hydrogel achieves rapid hemostasis. In an ethanol‐induced gastric ulcer model in rats, it demonstrates that the hydrogel effectively inhibits gastric ulcer bleeding by 92% within 24‐h, exhibiting efficacy that surpasses that of omeprazole medicine, a commonly used clinical treatment. This enhanced performance is attributed to the synergistic effects of the CMCs hydrogel and TCP‐25 peptide in effectively achieving hemostasis, inhibiting bacterial growth, and promoting gastric wound healing in acute or chronic bleeding gastric ulcers. Consequently, the present work offers promising clinical applications for rapid hemostasis and wound healing in gastric ulcers. [ABSTRACT FROM AUTHOR]

The endometrium, the inner lining of the uterus, assumes a crucial role in the female reproductive system. Disorders and injuries impacting the endometrium can lead to profound consequences, including infertility and compromised women's overall health. Recent advancements in stem cell research have opened new possibilities for the treatment and repair of endometrial issues. In the present study, we constructed a degradable hydrogel by loading adipose‐derived stem cells (ADSCs) and melanin nanoparticles (MNP). In vitro cell experiments validated the biocompatibility of the prepared hydrogels and their adeptness in encapsulating ADSCs. Subsequently, we explored the impact of hydrogel@ADSC@MNP constructs in the healing process of uterine injury in mice. The results indicated that hydrogel@ADSC@MNP could augment endometrial thickness and ameliorate endometrial interstitial fibrosis. The injured tissue adjacent to hydrogel@ADSC@MNP constructs exhibited higher levels of bFGF, IGF‐1, and VEGFA compared with the corresponding tissue in mice receiving hydrogel constructs alone or in the model group. Furthermore, the hydrogel@ADSC@MNP system enhanced the proliferative capabilities of uterine endometrial cells, facilitated microvasculature regeneration, and reinstated the endometrium's capacity to receive the embryos. Our findings strongly suggest that the hydrogel@ADSC@MNP system holds significant promise for repairing and regenerating damaged endometrium. [ABSTRACT FROM AUTHOR]

Most flexible human–machine interfaces emulate the tactile system of the skin, which has the risk of contact damage. Additionally, contact deformation often leads to a hysteresis response. Non‐contact interaction can address these problems. Inspired by the electroreception capabilities of the elephantnose fish, this study introduces a non‐contact sensing model employing monopolar controlled ionic hydrogel. Compared to most existing mutual capacitive non‐contact sensing models, this model not only boosts responsivity by over 3.5 times but also streamlines the sensing architecture. Utilizing this sensing model, a flexible non‐contact human–machine interface is developed by organizing three differently shaped hydrogels into an asymmetric configuration. This device reliably discerns six non‐contact gestures using machine learning algorithms and supports at least eleven interactive functions by detecting the duration of gestures, enabling continuous real‐time control over external devices. This advancement heralds a more liberated paradigm of human–machine interaction with promising implications for the Internet of Things. [ABSTRACT FROM AUTHOR]

AbstractDecellularized tissue hydrogels, especially that mimic the native tissue, have a high potential for tissue engineering, three-dimensional (3D) cell culture, bioprinting, and therapeutic agent encapsulation due to their excellent biocompatibility and ability to facilitate the growth of cells. It is important to note that the decellularization process significantly affects the structural integrity and properties of the extracellular matrix, which in turn shapes the characteristics of the resulting hydrogels at the macromolecular level. Therefore, our study aims to identify an effective chemical decellularization method for sheep lung tissue, using a mixing/agitation technique with a range of detergents, including commonly [Sodium dodecyl sulfate (SDS), Triton X-100, and 3-((3-cholamidopropyl) dimethylammonio)-1-propanesulfonate] (CHAPS), and rarely used (sodium cholate hydrate, NP-40, and 3-[N,N-Dimethyl(3-myristoylaminopropyl)ammonio]propanesulfonate) (ASB-14). After the effectiveness of the used detergents on decellularization was determined by histological and biochemical methods, lung derived decellularized extracellular matrix was converted into hydrogel. We investigated the interactions between lung cells and decellularized extracellular matrix using proliferation assay, scanning electron microscopy, and immunofluorescence microscopy methods on BEAS-2B cells in air-liquid interface. Notably, this study emphasizes the effectiveness of ASB-14 in the decellularization process, showcasing its crucial role in removing cellular components while preserving vital extracellular matrix biological macromolecules, including glycosaminoglycans, collagen, and elastin. The resulting hydrogels demonstrated favorable mechanical properties and are compatible with both cell-cell and cell-extracellular matrix interactions. [ABSTRACT FROM AUTHOR]

Injectable hydrogels have emerged as versatile materials with potential applications in various fields, including biomedicine, lubrication, adhesion, surface coatings, and tissue engineering. However, the critical aspect of spreading and wetting on various substrates, which is essential for obtaining significant interfacial properties, has not been adequately addressed. This work presents an approach to prepare hydrogel coatings on kinds of substrates through the superspreading of polyelectrolyte complex solution during its liquid‐liquid phase inversion process. Due to the low interfacial tension, the solution spreads and wets various surfaces underwater driven by osmotic pressure, improving the contact area and interface integration. Combined with the simultaneous sol‐gel transition through electrostatic interaction, it forms a stable and homogeneous hydrogel coating. The hydrogel coating possesses control thickness (4–8 µm), improved hydrophilicity (CA decrease from 102° to 10°), interfacial toughness (increase from 70 to 455 J m−2), and lubrication performance (coefficients of friction decrease from 0.712 to 0.112). The work provides an excellent opportunity to investigate the spreadability and wettability in a water/water/solid three‐phase system and develop functional hydrogel coatings for various applications. [ABSTRACT FROM AUTHOR]

The development of synthetic selective membranes that separate materials of similar sizes, charges, and/or polarities remains a difficult challenge, and looking towards biology provides inspiration for new designs. In this work, a series of cholera toxin binding peptides (CTBPs) are identified, spanning a range of binding inhibitions, and integrated into chemically cross‐linked cholera toxin binding gels (CTBGs) via thiol‐Michael polycondensation reactions. All gels demonstrate rheological profiles consistent with elastic solids. The CTBGs are probed via small‐angle neutron scattering and exhibit a correlation length, ξ, smaller than most proteins (1.3–2.5 nm). Thus, an effective entropic mesh is formed to block non‐targeted proteins. However, the CTBGs have a dynamic mesh size, Ξ, that is larger than cholera toxin (CT) to allow the transport of target proteins. The CTBGs with the highest binding inhibitions both show high selectivity and permeation of CT, rejecting all other tested proteins. In total, two new highly selective CTBGs are synthesized and validated for use in cholera toxin remediation. Together, this platform demonstrates the wide applicability of selectively‐diffusive materials for difficult separations. [ABSTRACT FROM AUTHOR]

4-Nitrophenol (4-NP) is an important industrial intermediate that poses serious ecological risks and affects human health if exposed directly to the environment without treatment. 4-NP is less toxic when reduced to 4-aminophenol (4-AP) and can be used in a wide range of applications. In this study, copper-loaded chitin/hydroxyapatite composite hydrogels (Ch/HA-Cu) were prepared by in situ reduction of Cu2+. The catalytic reduction performance of Ch/HA-Cu catalysts for 4-NP was investigated. 10 mg of Ch/HA-Cu catalysts reduced 4-NP (0.1 mM) in 4 min. The increase in the starting concentration of 4-NP significantly improved the reduction of 4-NP, but also prolonged the reaction time. The activation energy required for the reduction of 4-NP by Ch/HA-Cu was about 40.68 kJ mol−1 and the reaction rate constant k was 0.61 min−1. The interfering substances affected the replacement efficiency of the reactants on the surface of Ch/HA-Cu and slowed down the reaction. The catalytic efficiency of Ch/HA-Cu for the reduction of 4-NP still reached more than 97% after five cycles of experiments, showing excellent catalytic activity and reaction stability for 4-NP, indicating that the prepared Ch/HA-Cu can be used as an economical and reusable multiphase reactor for the abatement of organic pollutants. [ABSTRACT FROM AUTHOR]

Biobased hydrogels have been widely used in drug delivery, tissue engineering and biosensors due to their abundance, non-toxicity and biocompatibility. However, constructing fully biobased hydrogels with good mechanical performance still remains a challenge. Herein, a double network (DN) hydrogel consisting of oxidized hydroxypropyl guar gum (OHPG) and gelatin (Gel) was fabricated via Schiff base reaction. The Gel-OHPG hydrogel had an elongation at break of 497%, a tensile stress of 0.44 MPa and a compressive stress of 25.91 MPa. Then, the mechanical properties of the hydrogel were further enhanced through immersing it in an ammonium sulfate (AMS) solution due to the Hofmeister effect. Its elongation could reach 629% and the corresponding tensile toughness and compressive stress were 3.86 MPa and 59.55 MPa, respectively. The conductivity of the hydrogel was 0.86 S m−1. Furthermore, the Gel-OHPG hydrogel was fabricated as a flexible sensor, and it could accurately monitor human joint motions such as fingers, wrists, knees, elbows, throat and neck. Henceforth, the Gel-OHPG hydrogel prepared using fully natural polymers has promising potential in flexible sensors and tissue engineering. [ABSTRACT FROM AUTHOR]

In recent years, the utilization of natural sources for hydrogel preparation has surged, driven by their economic and environmental advantages. The use of natural polysaccharides offers distinct benefits over synthetic counterparts, including non-toxicity, cost-effectiveness, biodegradability, and widespread availability. This study explores the enhanced properties of natural hydrogels derived from mucilages extracted from okra pods and chia seeds. The hydrogels, fortified with zinc oxide nanoparticles and loaded with nettle extract as herbal drug, demonstrate improved mechanical strength and elastic behavior. The characterization of prepared hydrogel through FTIR, SEM, TGA, and RMS techniques, along with rheological analysis, reveals enhanced features. The release pattern and kinetics of nettle extract in the buffered medium were studied. The result of nettles extract release showed that it is most suitable for the zero-order model, which states that during the release process, the drug concentration in the body remains constant and the release is occurred by the Fickian mechanism. Swelling behavior studies showed increased water absorption capacity in nanocomposite hydrogels. Antibacterial assessments confirmed significant efficacy against Staphylococcus, Streptococcus, Escherichia coli, and Yersinia bacteria. These suitable properties indicate that the synthesized nanocomposite hydrogel is a good formulation to be used as a drug delivery system. [ABSTRACT FROM AUTHOR]

A hydrogel consisted of poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAAm-co-AA) and Prussian blue (PB) was synthesized for a cargo carrier by controlling the release of organic dye under near infrared (NIR) light. The AA moiety of the hydrogel provided chemical bonding with Fe (III) ions for further PB formation. Biocompatible, NIR-responsive PB generated heat and the heat was transferred to the hydrogel. The NIPAAm moiety in the hydrogel was shrunken because of the low critical solution temperature behavior of the hydrogel, and the hydrogel released the loaded dye with 62%. These results suggest dye-loaded hydrogel as a prospective platform for light-triggered carriers. [ABSTRACT FROM AUTHOR]

Anisotropic bilayer hydrogel actuators are high‐performance materials engineered to exhibit unique and programmable mechanical properties, including varying stiffness and directional bending capabilities, by integrating two hydrogel layers with distinct responses to stimuli. However, programming and constructing these bilayer hydrogels remains challenging due to their lack of mechanical robustness, rapid responsiveness, and dual‐actuation capabilities, which hinder their practical applications and further development. Hence, developing a double‐actuating bilayer hydrogel with a temperature‐responsive and auxiliary layer could address these challenges. Herein, an anisotropic hydrogel actuator is developed using a simple and economical casting method, in which a unique multiasymmetric bilayer structure locked by an interfacial is fabricated. The as‐prepared hydrogels demonstrate exceptional temperature‐responsive bending abilities, achieving a 360 °C angle in just 8 s, and exhibit adaptive, complex shape transformation capabilities tailored to specific needs (e.g., two dimensional (2D) letters, leaves, flower, and butterfly hydrogel). Furthermore, the hydrogels possess excellent shape memory, mechanical strength, and conductivity. Additionally, gripper and humidity alarm prototypes made from the hydrogel are also successfully developed, illustrating that this approach opens new avenues for designing and producing smart hydrogels with practical applications in sensors, smart humidity alarms, and on‐demand smart grippers and actuators. [ABSTRACT FROM AUTHOR]

Periodontitis is a chronic infection where abnormal host‐microbiota interactions alter the oral microbiome, trigger a proinflammatory immune response, and cause inflammatory alveolar bone loss. While antibiotics are occasionally necessary for treating periodontitis, their use must be carefully managed to prevent the development of drug resistance and oral dysbiosis. Therefore, it's crucial to develop new treatment strategies for periodontitis that reduce antibiotic dependence while effectively controlling the inflammation triggered by bacteria. In this study, a hydrogel is engineered by grafting cationic polyamidoamine dendrimers (PAMAM‐G3) onto the oxidized carboxymethyl cellulose (OCMC) backbone, resulting in an injectable cationic hydrogel (OCMC‐PAMAM‐G3, O‐P). This hydrogel can capture anionic microbial‐associated molecular patterns (MAMPs), such as lipopolysaccharides (LPS) and cell‐free DNA (cfDNA). These findings reveal that using O‐P application circumvents the disruption of the oral mucosa microbiome caused by traditional antibiotics. Additionally, this hydrogel can mitigate inflammatory alveolar bone loss in a ligature‐induced periodontitis mouse model by alleviating the LPS/cfDNA‐TLR4/9 pathway. Moreover, topical administration of O‐P hydrogel has no significant adverse effects on the oral mucosa microbiome while improving the local subgingival microbiome. The study highlights a strategy targeting MAMPs while avoiding antibiotics, as it can mitigate the bacteria‐triggered proinflammatory immune response and potentially preserve oral dysbiosis. [ABSTRACT FROM AUTHOR]

Bone defects caused by tumors, osteoarthritis, and osteoporosis attract great attention. Because of outstanding biocompatibility, osteogenesis promotion, and less secondary infection incidence ratio, stimuliresponsive biomaterials are increasingly used to manage this issue. These biomaterials respond to certain stimuli, changing their mechanical properties, shape, or drug release rate accordingly. Thereafter, the activated materials exert instructive or triggering effects on cells and tissues, match the properties of the original bone tissues, establish tight connection with ambient hard tissue, and provide suitable mechanical strength. In this review, basic definitions of different categories of stimuli-responsive biomaterials are presented. Moreover, possible mechanisms, advanced studies, and pros and cons of each classification are discussed and analyzed. This review aims to provide an outlook on the future developments in stimuli-responsive biomaterials. [ABSTRACT FROM AUTHOR]

Appropriate mechanical properties is one of the prerequisites for the applications of hydrogels, where cross‐linker is a crucial component in manipulating such mechanical property. Herein, acryloyl‐functionalized polyethyleneimine (APEI) was innovatively used as novel functional cross‐links to optimize the mechanical properties of polyacrylamide (PAM) hydrogels. APEI cross‐links were synthesized by simply adding acryloyl chloride into polyethyleneimine in aqueous solution. The chemical structures of APEI were confirmed by Fourier transform infrared and nuclear magnetic resonance spectra. APEI possessed massive highly acryloyl functional groups that can serve as multifunctional cross‐linking centers for the polymerization of monomers via covalent bonding interactions. These covalent bonds are favorable for constructing a firm 3D cross‐linked networks for hydrogels to withstand deformations, endowing hydrogels with the improved mechanical properties. The tensile strength with an elongation at break for the hydrogels can reach 234 kPa and 18.4‐fold, respectively. In addition, even the hydrogels can bear cyclic mechanical loads and deformations for 50 cycles at 5‐fold stain, indicating a good fatigue resistance. The deformability of APEI cross‐links clusters under stretching was responsible for the stretchability of PAM/APEI hydrogels. This work provides a simple strategy to enhance the mechanical properties of hydrogels via the development of novel APEI chemical cross‐linker. [ABSTRACT FROM AUTHOR]

Conductive hydrogels are gaining significant attention as promising candidates for the fabrication materials for flexible electronics. Nevertheless, improving the tensile properties, hysteresis, durability, adhesion, and electrochemical properties of these hydrogels remains challenging. This work reports the development of a novel semi‐interpenetrating network poly(ionic liquid) hydrogel named PATV, via the in situ polymerization of acrylamide, N‐[Tris(hydroxymethyl)methyl] acrylamide, and 1‐vinyl‐3‐butylimidazolium tetrafluoroborate. The density functional theory calculations reveal that the poly(ionic liquid) in the hydrogel network acts as physical cross–linking points to construct hydrogen‐bond networks. Furthermore, the hydrogen‐bond networks dissipate energy efficiently and quickly, and thus stress concentration and hysteresis are avoided. The prepared hydrogel has a low hysteresis (9%), high tensile properties (900%), fast response (180 ms), high sensitivity (gauge factor = 10.4, pressure sensitivity = 0.14 kPa−1), and wide sensing range (tensile range: 1–600%, compression range: 0.1–20 kPa). A multifunctional sensor designed based on the designed hydrogel enables real‐time, rapid, and stable response‐ability for the detection of human movement, facial expression recognition, pronunciation, pulse, handwriting, and Morse code encryption. Furthermore, the assembled triboelectric nanogenerator displays an excellent energy harvesting capability, thus highlighting its potential application in self‐powered flexible wearable electronic devices. [ABSTRACT FROM AUTHOR]

The musculoskeletal system, which is responsible for weight‐bearing, movement, and organ protection, faces many disorders arising from injuries, diseases, and trauma that affect millions of people worldwide, resulting in a decreased quality of life and socioeconomic burden. Tissue engineering is at the forefront of current research on tissue regeneration and demonstrates great potential for musculoskeletal tissue repair. Among the numerous grafts available, adhesive hydrogels have demonstrated potential for tissue applications. Despite the surge in the development of bioadhesive hydrogel formulations in recent years, the absence of an evaluation protocol for their formulation has led to the emergence of numerous similar products that do not fully meet the clinical requirements for applicability in musculoskeletal tissue regeneration. This review aims to address this gap by first discussing the design considerations for an ideal bioadhesive hydrogel relevant to successful musculoskeletal tissue repair. By thoroughly reviewing recent research advances in bioadhesive hydrogels, with a particular focus on their applications in facilitating musculoskeletal tissue repair, improvements are proposed in the current evaluation criteria for the development of novel bioadhesive hydrogels for musculoskeletal tissue applications, and several key challenges and research directions for their implementation are summarized. [ABSTRACT FROM AUTHOR]

Biomimetic electronic skins (e‐skins) are widely used in wearables, smart prosthesis and soft robotics. However, multimodal e‐skins, especially those based on hydrogels, face multiple challenges for practical applications, involving multi‐sensing signal mutual interference, low breathability and stretchability. Here, a breathable and stretchable multimodal e‐skin with a multilayer film microstructure is developed to achieve self‐calibrated sensing of any two of three stimuli: strain, temperature, and humidity, with minimal crosstalk. Hydrogel fibers with different shapes are designed for strain and temperature sensing modules, and the hydrogel film is developed as a humidity sensing module. The multimodal e‐skin exhibits impressive sensing performance, including a low strain detection limit (0.03%), strain linearity (R2 = 0.990), high‐temperature sensitivity (1.77%/°C), and a wide humidity detection range (33–98% RH). Interestingly, due to the directional anisotropy in strain sensitivity of different shaped fibers, the e‐skin realizes self‐calibrated detection of strain and temperature in different directions. By introducing porous elastomer encapsulation membranes, the breathability and wearing comfort of the e‐skin are attained, while the high stretchability (100% strain) is maintained. Furthermore, a personalized human‐machine interaction system is created by integrating the e‐skin with a wireless circuit to realize real‐time and wireless gesture recognition, physiological signals monitoring, and smart prosthesis. [ABSTRACT FROM AUTHOR]

Three dimensional (3D) bioprinting using photocrosslinkable hydrogels has gained considerable attention due to its versatility in various applications, including tissue engineering and drug delivery. Egg White (EW) is an organic biomaterial with excellent potential in tissue engineering. It provides abundant proteins, along with biocompatibility, bioactivity, adjustable mechanical properties, and intrinsic antiviral and antibacterial features. Here, a photocrosslinkable hydrogel derived from EW is developed through methacryloyl modification, resulting in Egg White methacryloyl (EWMA). Upon exposure to UV light, synthesized EWMA becomes crosslinked, creating hydrogels with remarkable bioactivity. These hydrogels offer adjustable mechanical and physical properties compatible with most current bioprinters. The EWMA hydrogels closely resemble the native extracellular matrix (ECM) due to cell‐binding and matrix metalloproteinase‐responsive motifs inherent in EW. In addition, EWMA promotes cell growth and proliferation in 3D cultures. It facilitates endothelialization when investigated with human umbilical vein endothelial cells (HUVECs), making it an attractive replacement for engineering hemocompatible vascular grafts and biomedical implants. In summary, the EWMA matrix enables the biofabrication of various living constructs. This breakthrough enhances the development of physiologically relevant 3D in vitro models and opens many opportunities in regenerative medicine. [ABSTRACT FROM AUTHOR]

Soluble biochemical agents are being employed to generate kidney organoids from human‐induced pluripotent stem cells. However, this soluble factor approach does not consider the effect of the mechanical environment on lineage commitment. Here, a mechanoresponsive nano‐environment with cell‐adhesive properties composed of supramolecular hydrogelators that co‐assemble into fibrous superstructures to form a transient network is presented, which is used to encapsulate kidney organoids. The delayed sol‐gel transition of the transient network enables fibrous superstructures to diffuse into the densely packed extracellular organoid space during the encapsulation procedure. This allows the mechanoresponsive matrix to induce a biological response beyond the organoid‐hydrogel border, and tune glomerulogenesis inside kidney organoids. In this manner, biomaterials are used as a complementary tool to soluble biochemical agents in tuning lineage commitment and refining organoid maturation. [ABSTRACT FROM AUTHOR]

Evaluating the biodegradability and biocompatibility of hydrogels is essential for identifying materials suitable for biomedical applications. This study describes the fabrication of hydrogels utilizing physiological‐soluble chitosan (N‐succinyl chitosan, NSC) crosslinked with dialdehyde guar gum (Oxidized Galactomannan, OxGM) via the Schiff‐base reaction. Hydrogels with varying volumetric ratios of NSC/OxGM, resulting in distinct NH2/CHO functional group ratios and crosslinking degrees, underwent comprehensive characterization using Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), swelling, and scanning electron microscopy (SEM). Gelation time (tgel) is assessed by rheological analysis (tgel = G′ > G″), where tgel increased with higher crosslinking density, reaching a maximum value of ≈80 s. Biodegradation analysis in phosphate‐buffered saline (PBS) with lysozyme (13 mg L−1) revealed that the crosslinking degree significantly influenced degradation, with lower crosslinking associated with an elevated degradation profile. Moreover, cell viability assays with fibroblastic cells demonstrated minimal cytotoxicity, but an increase in free aldehyde groups correlated with decreased cell viability. For the 75C25C hydrogel, the compressive test yielded a Young's modulus value of 67.2 kPa (±8.5). These results imply that the hydrogels developed exhibit favorable biodegradability and biocompatibility, making them promising candidates for diverse biomedical applications. [ABSTRACT FROM AUTHOR]

Reconfigurability within hydrogels has emerged as an attractive functionality that can be used in information encryption, cargo/delivery, environmental remediation, soft robotics, and medicine. Here micro‐patterned polymer hydrogels capable of temperature‐dependent reconfigurability are fabricated. For this, the hydrogels are provided with micron‐sized Pickering emulsion droplets stabilized by magnetic particles, which are capable of harnessing energy from external force fields. The droplets can both migrate under magnetic field gradients and heat the environment when laser irradiated. These functions not only affect a single compartment but have higher‐order effects on the mesoscale, thanks to the temperature‐responsiveness of the polymeric network. This double responsiveness is exploited to control the spatial organization of hundreds of droplets within the hydrogel matrix and form predesigned and sophisticated patterns. Furthermore, pattern self‐reconfiguration driven by the droplets themselves upon laser irradiation is induced. Finally, we show that due to their internal liquid phase, the droplets can be used as reservoirs of hydrophobic nutrients for living cells (i.e., Yarrowia lipolytica yeast) in the solid‐like environment of the polymeric network, and demonstrate communication between the droplets and the cells to facilitate nutrient uptake. Altogether, the results provide opportunities for the development of stimuli‐sensitive polymer hydrogels with post‐synthesis reprogrammable response using micro‐compartments as building blocks. [ABSTRACT FROM AUTHOR]

Biomaterial wound dressings, such as hydrogels, interact with host cells to regulate tissue repair. This study investigates how crosslinking of gelatin-based hydrogels influences immune and stromal cell behavior and wound healing in female mice. We observe that softer, lightly crosslinked hydrogels promote greater cellular infiltration and result in smaller scars compared to stiffer, heavily crosslinked hydrogels. Using single-cell RNA sequencing, we further show that heavily crosslinked hydrogels increase inflammation and lead to the formation of a distinct macrophage subpopulation exhibiting signs of oxidative activity and cell fusion. Conversely, lightly crosslinked hydrogels are more readily taken up by macrophages and integrated within the tissue. The physical properties differentially affect macrophage and fibroblast interactions, with heavily crosslinked hydrogels promoting pro-fibrotic fibroblast activity that drives macrophage fusion through RANKL signaling. These findings suggest that tuning the physical properties of hydrogels can guide cellular responses and improve healing, offering insights for designing better biomaterials for wound treatment. Impaired wound healing that leads to scar remains a clinical challenge. Here, the authors study the effects of hydrogel crosslinking on cellular behavior in skin wounds and its effect on immune and stromal cell activity. [ABSTRACT FROM AUTHOR]

Developing antiswelling hydrogel that retains their low modulus and has three‐dimensional (3D) printability to application in the biomedical field is a current critical issue. Here, we synthesized 3D printing ink consist of poly(acrylic acid‐acrylamide‐allyloxypolyethyleneglycol) (P(AA‐Am‐APEG)) and nanosilica (SiO2) by free radical polymerization, immersed the hydrogel precursor printed by ink in ferric chloride solution to prepare a low modulus, antiswelling, and conductive hydrogel. In the physical cross‐linking network, the coordination interaction and hydrogen bonds contributed to excellent mechanical properties and nSiO2 regulated rheological behavior of ink. Especially, P(AA‐Am‐APEG) molecular chain was a structure containing of APEG branch chain, which could endow antiswelling (the equilibrium swelling rate was only 7% in deionized water) and low modulus (Young's modulus was less than 100 kPa) to hydrogel. The tensile stress could still maintain 90% of the original value after soaking for 24 h. In addition, the existence of iron and chloride ions provided high sensitive deformation‐dependent conductivity to hydrogel. Therefore, the strategy of controlling the swelling and modulus by branch chains would expand the application of hydrogel in biosensors and other fields. [ABSTRACT FROM AUTHOR]

Wound infections pose a major healthcare issue, affecting the well‐being of millions of patients worldwide. Effective intervention and on‐site detection are important in wound management. However, current approaches are hindered by time‐consuming analysis and a lack of technology for real‐time monitoring and prompt therapy delivery. In this study, a smart wound patch system (SWPS) designed for wireless closed‐loop and in‐situ wound management is presented. The SWPS integrates a microfluidic structure, an organic electrochemical transistor (OECT) based sensor, an electrical stimulation module, and a miniaturized flexible printed circuit board (FPCB). The OECT incorporates a bacteria‐responsive DNA hydrogel‐coated gate for continuous monitoring of bacterial virulence at wound sites. Real‐time detection of OECT readings and on‐demand delivery of electrical cues to accelerate wound healing is facilitated by a mobile phone application linked with an FPCB containing low‐power electronics equipped with parallel sensing and stimulation circuitry. In this proof‐of‐concept study, the functionality of the SWPS is validated and its application both in vitro and in vivo is demonstrated. This proposed system expands the arsenal of tools available for effective wound management and enables personalized treatment. [ABSTRACT FROM AUTHOR]

Conductive hydrogels, characterized by their unique features of flexibility, biocompatibility, electrical conductivity, and responsiveness to environmental stimuli, have emerged as promising materials for sensitive strain sensors. In this study, a facile strategy to prepare highly conductive hydrogels is reported. Through rational structural and synthetic design, silver nanowires (AgNWs) are incorporated into poly(N‐acryloyl glycinamide) (PNAGA) hydrogels, achieving high electrical conductivity (up to 0.88 S m−1), significantly enhanced mechanical properties, and elevated deformative sensitivity. Furthermore, surface modification with polyhexafluoropropylene oxide (PHFPO) has substantially improved the water retention capacity and dressing comfort of this hydrogel material. Based on the above merits, these hydrogels are employed to fabricate highly sensitive wearable strain sensors which can detect and interpret subtle hand and finger movements and enable precise control of machine interfaces. The AgNWs/PNAGA based strain sensors can effectively sense finger motion, enabling the control of robotic fingers to replicate the human hand's gestures. In addition, the high deformative sensitivity and elevated water retention performance of the hydrogels makes them suitable for flow sensing. These conceptual applications demonstrate the potential of this conductive hydrogel in high‐performance strain sensors in the future. [ABSTRACT FROM AUTHOR]