Search Results (425)

Replicating the nonlinear, pressure-dependent mechanical behavior of native arteries remains a central challenge in small-diameter vascular graft design, where compliance mismatch between synthetic grafts and host vessels is strongly linked to graft failure. Building on a silk fiber-reinforced alginate–polyacrylamide interpenetrating polymer network (IPN) hydrogel platform, we investigated whether biomimetic vascular structural motifs, specifically fiber reorientation and crimp, can be used as programmable design parameters to tune the tensile and pressure-dependent mechanical response of tubular constructs toward native coronary artery behavior. Three architectures were fabricated: a cross-plied (CP) baseline, a 25° reoriented configuration, and a crimped CP configuration. Under internal pressurization, fiber reorientation and crimp significantly increased compliance at low physiological pressures, with a consistent directional trend across the full pressure range, by extending the low-stiffness toe region preceding fiber recruitment while preserving tensile stiffness. Across the investigated pressure range, all architectures exhibited compliance within the reported range of native coronary arteries, with crimped constructs producing pressure–diameter behavior that most closely resembled young coronary arteries, whereas the CP baseline more closely resembled aged coronary arteries. These findings demonstrate that biomimetic structural motifs, without altering material composition, can serve as programmable design parameters for engineering vascular mechanics, enabling a single material platform to reproduce distinct physiological mechanical phenotypes through architecture alone. Full article

Wearable rehabilitation monitoring requires soft strain sensors with mechanical robustness, stable electromechanical responses, and intelligent motion recognition capability. Here, we report a poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double−network hydrogel strain sensor for rehabilitation−oriented wearable monitoring. The hydrogel was prepared by ultraviolet ray (UV)−initiated acrylamide polymerization followed by freeze−thaw−induced PVA crystallization, forming a covalent PAM network interpenetrated with a physically crosslinked PVA network. The resulting hydrogel possessed a compact porous structure, improved stretchability, and stable deformation recovery. The optimized sensor exhibited a tensile strength of approximately 0.52 MPa, an elongation at break of approximately 480%, a response time of 0.12 s, and a recovery time of 0.17 s. It generated repeatable resistance signals under cyclic strain, finger bending, wrist motion, and grip training. Furthermore, the sensor enabled morse−code information transmission and support vector machine (SVM)−based recognition of rehabilitation−related hand states, including straight, bend, and clench. This work provides a soft hydrogel sensing platform for real−time rehabilitation−oriented hand motion, while morse−code encoding provides auxiliary assistance and an emergency communication function. Full article

Cu-based interpenetrating phase composites (IPCs) are candidate materials for sliding-contact applications in which thermal management, wear resistance, and electrical transport must be balanced. Herein, Cu–(CrW_x)C IPCs were fabricated by pressureless infiltration using nominal W-addition indices x = 0, 10, 25, and 50, corresponding to 0, 10, 25, and 50 g W added per 100 g Cr₂O₃ rather than final W mass fractions. Microstructural characterization indicates that W addition changes the scale and connectivity of W-containing carbide regions while preserving a continuous Cu-rich network. Representative quasi-static compression curves illustrate the large-strain load-bearing response but are interpreted descriptively because independent replicate specimens were not available for every composition under an identical test matrix. All composites retain room-temperature electrical conductivities of 39.23–40.44% of the International Annealed Copper Standard (IACS). Cu–(CrW10)C reaches a thermal conductivity of 208.27 W m⁻¹ K⁻¹ at 500 °C and the lowest specific wear rate of 2.42 × 10⁻⁶ mm³ N⁻¹ m⁻¹. Worn-surface and cross-sectional observations show that its low material loss coexists with localized cracking and adhered/detached features, whereas higher nominal W additions promote carbide fragmentation, interfacial separation, and hard-debris-mediated abrasion. The thermo-tribological performance index (TTPI) and electrical-thermal-wear balance index (ETWBI), used as internal screening metrics, identify Cu–(CrW10)C as the most balanced composition within the present four-composition dataset. These results demonstrate that wear resistance is governed by the stability of the skeleton-supported tribologically modified layer and continuous Cu-network transport rather than by hardness or nominal W addition alone. Full article

In the contemporary era of minimally invasive surgery, injectable biomaterial scaffolds have demonstrated significant potential in bone tissue engineering (BTE). Completely injectable hydrogel substratum with microscale bone graft particulates delivered through a needle-shaped orifice shifts a new paradigm for surgical interventions in clinical settings. Despite growing interest in biopolymer-based BTE systems, clinically applicable delivery platforms and a mechanistic understanding of cell–material interactions remain limited. This study developed a dual-syringe auto-mix system capable of generating an in situ cross-linking hydrogel–mineral construct composed of gelatin–hydroxyphenyl propionic acid, hyaluronic acid–tyramine, horseradish peroxidase, hydrogen peroxide, and calcium phosphate particles of varying sizes. Material distribution, rheological and mechanical properties, and swelling were characterized. Goat bone marrow-derived mesenchymal stem cells served as the basis for examining how the composite affected cell viability, morphology, proliferation, contractility, osteogenic differentiation, mineralization, and chemotactic behavior. To determine whether these biological findings were supported mechanically, an ex vivo cone-beam computed tomography model was used to evaluate volumetric stability and resistance to deformation at the graft–host interface. Cross-linking established a stable internal microarchitecture while remaining compatible with cell viability and nutrient-dependent survival. Formation of the gelatin–hyaluronan (GH) network significantly increased the storage modulus relative to gelatin (G) alone, whereas subsequent calcium phosphate incorporation (GH-CP) preserved this mechanical competence while attenuating the volumetric expansion of GH. These physical characteristics were accompanied by more organized cell morphology, enhanced osteogenic differentiation, and mineral deposition throughout a larger portion of the matrix. Heterogeneous interpenetrating gap striation (HIGS) appeared in regions of cellular aggregation and matrix deposition, and a new conceptualization of the osteogenic phenomenon, termed cling osteogenesis, has been proposed. These outcomes support an intricate relationship between early mechanical stabilization, mechanotransduction, and osteogenesis in injectable hydrogel–mineral systems. Full article

The development of antibacterial hydrogel with stretchable and self-healing properties is an urgent problem in the field of biomedical engineering. Herein, a series of hydrogels with antibacterial activity was successfully fabricated using polyvinyl alcohol (PVA), borax, 4-formylphenyl-β-D-allopyranoside (HLC), 3,3′-dithiobis (propionohydrazide) (DPH) and ionic liquid, 1-aminopropyl-3-methylimidazolium bromide (C₃MimNBr). The hydrogels were formed via in situ crosslinking through multiple dynamic covalent bonds, primarily including borate ester bonds, imine bonds and acylhydrazone bonds. A Field Emission Scanning Electron Microscope (FE-SEM) revealed that the formed hydrogels possessed a typical three-dimensional network structure. Notably, the interpenetrating network structure endowed the hydrogels with excellent stretchability and self-healing capability, as demonstrated by their ability to be molded into various shapes and stretched up to five times their original length. Furthermore, the mechanical properties of the hydrogel were affected by the amount of the ionic liquid added. Antibacterial evaluation using the colony counting method showed that the hydrogels exhibited outstanding antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In summary, the multifunctional hydrogels, with favorable stretchability and antibacterial activity, represent promising alternative materials for biomedical engineering applications. Full article

Given the widespread contamination of water bodies by diverse pollutants, particularly heavy metal ions and organic dyes, there is an urgent need to develop efficient and sustainable biomass adsorbents. Lignin is rich in active groups such as phenolic hydroxyl and carboxyl groups, making it a natural adsorbent. However, its application is still hindered by limitations, including restricted solubility and low reactivity. Converting lignin into three-dimensional porous hydrogels not only overcomes the inherent structural brittleness of lignin-based materials but also accelerates the diffusion kinetics of pollutants through well-developed pore structures, thereby fully exposing the active adsorption sites. This paper systematically reviews the latest progress in lignin-based hydrogels for water treatment and discusses in depth the underlying logic of “structure construction–micromorphology–adsorption performance.” First, this review summarizes synthesis strategies ranging from molecular-level modification to morphology regulation, including nano-reinforcement, magnetic functionalization, and interpenetrating polymer networks. It then provides a pollutant-specific analysis of the adsorption mechanisms of lignin-based adsorbents. For heavy metal ions, such as Pb²⁺ and Cr(VI), removal is mainly associated with coordination/complexation, ion exchange, and redox reactions. For typical organic dyes, adsorption is primarily driven by π–π interactions, hydrogen bonding, and electrostatic attraction. The effects of environmental factors, such as pH, are also systematically discussed. Finally, considering current challenges related to mechanical strength, regeneration performance, and practical application, this review outlines future research directions for the development of multifunctional, integrated, and stimuli-responsive lignin-based adsorbents. Full article

The co-contamination of aquatic environments by antibiotic residues and organic dyes poses a serious threat to ecological security and human health, underscoring the urgent need for high-efficiency, recyclable, and environmentally benign adsorbents. Chitosan, a naturally occurring alkaline polysaccharide rich in reactive functional groups, has attracted considerable attention in water treatment applications. Nevertheless, its practical use is often constrained by intrinsic limitations, including poor stability in acidic media, inadequate mechanical strength, and difficulties in solid–liquid separation. Chitosan-based hydrogels, featuring unique three-dimensional cross-linked networks, high porosity, and strong hydrophilicity, provide efficient mass-transfer pathways for macromolecular contaminants and thus offer a promising strategy to overcome the shortcomings of pristine chitosan. This review comprehensively summarizes recent advances in chitosan-based hydrogel adsorbents, with a focus on elucidating the critical structure–performance relationships that link molecular/structural design to adsorption efficacy. First, fabrication strategies are systematically reviewed, ranging from molecular-level modifications (e.g., grafting, chemical cross-linking, and interpenetrating polymer networks) to macroscopic structural engineering approaches (e.g., mechanically reinforced, magnetic, and stimuli-responsive hydrogels). Subsequently, adsorption behaviors toward representative classes of antibiotics, including tetracyclines, fluoroquinolones, and sulfonamides, are critically examined, with emphasis on the underlying mechanisms such as electrostatic interactions, hydrogen bonding, π–π stacking, and pore-filling effects. In addition, the removal performance of chitosan-based hydrogels for organic dyes with varying charge characteristics is summarized, together with an analysis of how environmental factors (e.g., pH and ionic strength) influence adsorption kinetics and thermodynamics. Finally, key challenges related to mechanical robustness, selective adsorption, and recyclability are discussed, and future perspectives are proposed for the development of multifunctional, synergistic, and intelligent, environmentally responsive chitosan-based hydrogel materials. This review aims to provide systematic insights and guidance for the rational design of advanced hydrogel adsorbents for the treatment of complex wastewater. Full article

Membrane separation technology has been extensively applied to treat oily effluent given its high performance and ease of operation. However, conventional polymer membranes are resistant to natural degradation after use, leading to severe environmental concerns. Consequently, the development of biodegradable membranes that combine satisfactory oil–water separation performance with ecological safety has emerged as a critical research priority. In this work, we fabricated a biodegradable membrane consisting of chitosan (CS), sodium methacrylate (SMa) and polyvinyl alcohol (PVA) via electrospinning, with anionic super-hydrophilic polyacrylamide (PAM) incorporated to enhance wettability. No toxic chemicals were used throughout the fabrication process. The resulting membrane with an interpenetrating network and beaded structure not only rendered the crosslinked nanofiber more hydrophilic but also improved the porosity of membranes, which significantly enhanced the separation performance and fouling resistance of the membrane. Specifically, the CS/PVA/SMa-PAM membrane achieved a separation flux of 2.7 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹ for oil–water emulsions. After 20 emulsion separation cycles, the flux of the modified membrane was stable at 2.5 × 10⁴ L·m⁻²·h⁻¹·bar⁻¹. Benefiting from its excellent anti-fouling properties, high separation efficiency, eco-friendly biodegradability, and toxic-reagent-free fabrication, the as-prepared CS/PVA/SMa-PAM membrane offers a promising and sustainable option for oily wastewater treatment. Full article

Climate change and population growth are intensifying global food security challenges by reducing agricultural productivity and increasing reliance on fertilizers. In this context, developing sustainable and economically efficient agricultural solutions becomes essential. The study presents the synthesis of an interpenetrating polymer network (IPN) of hydrogels by combining bacterial cellulose (BC) with poly(acrylic acid) crosslinked with N, N-methylene-bis-acrylamide (PAA–co–MBA) via free radical copolymerization. To explore their potential as bioactive compound carriers, an ethanolic hydroalcoholic phytoextract (EHP) obtained from Hypericum perforatum L. and Melissa officinalis L. was directly encapsulated within the IPN hydrogels. The EHP is valued for its rich bioactive profile and antifungal, antimycobacterial, and antioxidant properties. The results of rheology measurements and thermal gravimetric analysis (TGA) revealed that incorporating BC into the IPN hydrogels significantly enhanced the mechanical stiffness, thermal resistance, and overall stability of the resulting IPN structures. Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) confirmed the structural organization and the porosity of the developed composite, as well as the successful fabrication of IPN hydrogels in the EHP medium. Under optimal conditions, the IPN hydrogels exhibited a reduced swelling capacity, thereby slowing the diffusion of the bioactive agents, reducing the application frequency, and enhancing the utilization efficiency. Taken together with the controlled-release performance, these findings demonstrate the potential of BC (PAA-co-MBA) IPN hydrogels as biodegradable and sustainable carrier systems for controlled delivery applications and suggest that they may be promising candidates for hydrogel-based agricultural delivery systems. Full article

Conventional photocurable resins suffer from low mechanical strength and poor thermal stability, which restrict their broader application in photopolymerization-based 3D printing technologies. Strategies such as inorganic fillers or interpenetrating polymer networks (IPNs) improve performance but often lead to high viscosity or long post-curing times. In this work, a high-performance photocurable resin system based on tris(2-hydroxyethyl) isocyanurate triacrylate (THEICTA) and N, N-dimethylacrylamide (DMAA) was developed, achieving low viscosity and direct room-temperature 3D printability. Partial substitution of DMAA with Tricyclodecanedimethanol diacrylate (DCPDA) further enhanced its mechanical and thermal properties. The optimized resin exhibited a tensile strength of 80.9 MPa, a flexural strength of 166.1 MPa, a glass transition temperature of 176.2 °C, and a low viscosity of 78.7 mPa·s with shrinkage below 10%. The heat deflection temperatures reached 168.1 °C under 1.80 MPa and 187.3 °C under 0.45 MPa. This study provides an effective strategy for developing high-strength and heat-resistant photocurable resins suitable for efficient room-temperature 3D printing applications. Full article

The subject of CO₂ subsurface storage security has never been more critical, and there is a need to explore the injection of functional materials that are capable of providing both conformance control and in situ CO₂ adsorption, thereby improving overall formation storage integrity. Herein, a molecular dynamics simulation method was used to investigate the adsorptive tendency of two variants of interpenetrating network (IPN) composite materials comprising amine-stabilized hydrophobically modified cellulose sulphates and methylene bisacrylamide crosslinked polyacrylamide. Using the COMPASS III force field and Metropolis Monte Carlo, the diffusivity and adsorption isotherms for CO₂ were determined in the IPN gels, respectively. The results indicate that the two interpenetrating networks D-I-AM-MBA-G-Cl and D-II-AM-MBA-G-Cl demonstrated reasonable CO₂ adsorption. In saline conditions, the adsorption was further enhanced with diffusion coefficients of 4.87 × 10⁻⁴ cm²/s and 2 × 10⁻⁶ cm²/s. The adsorption isotherm of D-I-AM-MBA-G-Cl closely fits the Sips equation, with a regression coefficient of 0.9996, while that of D-II-AM-MBA-G-Cl follows the Temkin isotherm with an R² value of 0.9885. This study revealed that carefully designed plugging agents with strong CO₂ adsorption tendencies can aid in the improvement of the geosequestration integrity of subsurface formations. Full article

Bacteria-infected wounds remain a major global biomedical challenge, with persistent inflammation and the lack of real-time monitoring significantly impairing wound healing. To address the limitations of conventional dressings, which often provide single-function and static treatment, we developed a multifunctional HP@CGA hydrogel based on methacrylated hyaluronic acid (HA-MA) and polyvinyl alcohol (PVA), incorporating chlorogenic acid (CGA) and bromothymol blue (BTB). In the presence of a photoinitiator, the methacryloyl groups of HA-MA undergo UV-induced free-radical polymerization to form a covalently crosslinked network, while PVA chains interact with the HA-MA backbone through hydrogen bonding and physical entanglement, resulting in a stable interpenetrating double-network structure. This integrated “treatment + monitoring” design offers a low-cost and convenient alternative to conventional wound dressings and separate sensing systems. Material characterization and preliminary experiments demonstrated that the hydrogel enabled visual pH detection within the range of 6.0–8.0 through distinct color changes. In addition, it exhibited excellent antibacterial activity, achieving antibacterial rates of 99.9% ± 0.08% against both S. aureus and E. coli. These results demonstrate the multifunctional performance of the HP@CGA hydrogel, including bacterial inhibition, inflammation alleviation, and real-time wound pH feedback, thereby providing a favorable microenvironment for infected wound healing. This work highlights the potential of HP@CGA hydrogel for precise and intelligent wound care. Full article

High-purity copper features excellent electrical conductivity but generally low mechanical properties. Adding a three-dimensional graphene network as reinforcement to make a copper–graphene metal matrix composite is promising for a wide range of applications with better mechanical performance and functional capabilities. However, direct application in a metal matrix is difficult due to unfavorable wetting, which causes poor dispersion and weak interfacial bonding in the graphene–metal system. Here, the powder metallurgy method was used to construct a three-dimensional continuous graphene network in the copper matrix combined with high-pressure torsion. Optimized deformation/thermomechanical treatment enhanced the microstructural development processed by the severe plastic deformation method of high-pressure torsion. The primary advantage of this hybrid process is that it enables us to achieve grains with a size in the ultra-fine or even nanoscale. A homogeneous equiaxed nanostructure without segregation was observed during microstructural characterization, with a grain size of ~300 nm. This study investigated structural development during progressive deformation, and the samples were evaluated from the viewpoint of grain size and grain boundaries. The process significantly increased the microhardness of the copper–graphene composite. The tensile strength reached ~500 MPa at room temperature. The interpenetrating structural feature of graphene promoted interfacial shear stress to a high level, whereas plastic deformation increased the dislocation density and grain boundaries, thus resulting in significantly enhanced load transfer strengthening and crack-bridging toughness simultaneously. Full article

The persistence of petrochemical plastics necessitates high-performance and recyclable alternatives, yet balancing mechanical robustness with component-level closed-loop recovery remains challenging for biomass-based plastic-replacement films. Here, a high-performance, thermo-malleable, and closed-loop recyclable composite film is constructed by integrating a highly crystalline enzyme-treated mulberry paper (Enzyme-MP) fiber network with an in situ formed polyimine (PI) vitrimer network via capillary-assisted infiltration. This process induces densification and extensive interfacial hydrogen bonding, forming a confined interpenetrating architecture that enhances stress transfer and restricts chain mobility. As a result, the composite film achieves a tensile strength of 70.3 MPa and a Young’s modulus of 2.37 GPa, together with excellent thermomechanical stability over a broad temperature range. The dynamic imine exchange enables thermo-malleability, allowing seamless self-welding and thickness-scalable lamination at 120 °C. The dense structure also acts as an effective barrier, reducing water uptake to 14.3% and providing resistance to various organic solvents. Furthermore, full-component closed-loop recycling is realized via room-temperature transimination, enabling selective depolymerization of the matrix while preserving the crystalline cellulose fiber network. This work demonstrates a viable strategy to integrate high-strength film performance, processability, and chemical recyclability in biomass-based composite films, while providing a basis for future cradle-to-cradle material circulation in recyclable plastic-replacement films. Full article

Chitosan-based interpenetrating networks (IPNs) have become highly attractive as advanced super-adsorbent materials due to their ability to combine a high density of functional adsorption sites with enhanced structural stability under physiological conditions. While chitosan offers intrinsic advantages such as biocompatibility, biodegradability, and chemical functionality, its adsorption efficiency, mechanical strength, and long-term stability may offer limited performance in complex biomedical environments. The formation of interpenetrating networks provides an effective strategy to overcome these limitations by interlacing chitosan with other polymer networks, resulting in a synergistic enhancement of physicochemical and adsorption properties. The formation of chitosan-based IPNs offers tunable control of network structure, porosity, swelling behaviour, and adsorption kinetics, which in turn results in enhanced retention and controlled interaction of drugs, biomolecules, toxins, and other therapeutic agents. Variations in polymer composition, crosslinking density, and network interactions further facilitate the controlled tailoring of adsorption properties for targeted biomedical applications. This review presents a comprehensive and critical assessment of recent progress in the fabrication, functionalization, and structure–property relationships of chitosan-based IPNs, with a main emphasis on their super-adsorbent behaviour. Furthermore, this review highlights key biomedical applications of IPNs, including controlled drug delivery, wound healing systems, tissue engineering scaffolds, detoxification platforms, and biosensing devices. Current issues in scalability, stability, and clinical translation are discussed, as well as future perspectives that highlight the potential of chitosan-based IPNs as high-performance, sustainable super-adsorbent materials for advanced biomedical technologies. Full article