Electrospun PCL/PVA core-sheath nanofibres enabling staged antibiotic and peptide delivery for diabetic foot ulcer dressings.

This study demonstrates active control of terahertz (THz) transmission by exploiting the humidity-driven swelling of a submicron poly(vinyl alcohol) (PVA) film integrated with metallic nanoresonators. Conventional THz modulators typically require bulk-like membranes tens of micrometers thick to compensate for weak light-matter interaction, which inevitably results in slow, diffusion-limited response times. In contrast, our approach utilizes field confinement near nanometer gaps to achieve high modulation depth with an ultrathin layer, offering a potential route to high-speed operation. Under 90% relative humidity, the 193 nm PVA film swells to 380 nm, exhibiting a rapid response time of 373 ms─nearly three times faster than 1.25 μm films. The hybrid structure achieves a 13.6% transmission modulation, driven by a localized dielectric transition at electric-field hot-spots. These findings provide a robust strategy for high-performance THz metasurfaces that bypass the traditional trade-off between modulation depth and response speed.

Optimized polysulfone/polyethylene glycol forward osmosis membranes with a poly(vinyl alcohol)/glutaraldehyde crosslinked interlayer for high water flux and low salt leakage

Periodontitis is a biofilm-induced chronic inflammatory disease characterized by progressive alveolar bone loss and eventual tooth loss. Here, we developed a core-shell microneedle (MN) system featuring a rapidly dissolvable hyaluronic acid (HA) backing layer for localized periodontal therapy. Upon insertion, the HA backing rapidly dissolves upon saliva contact, enabling detachment of the patch substrate while retaining the functional microneedle tips within gingival tissues. The MNs comprise a ZIF-8-loaded, reactive oxygen species (ROS)-responsive poly(vinyl alcohol)-4-(2,3-dihydroxypropylamino)methylphenylboronic acid (PVA-TSPBA) shell and a gelatin methacrylate (GelMA) core encapsulating a cerium-metformin (CeMet) complex. In inflamed periodontal tissues, the PVA-TSPBA shell rapidly responds to the oxidative microenvironment, enabling early Zn2+ availability for effective antibacterial activity, while the CeMet-loaded core provides sustained antioxidant and immunomodulatory effects. The Ce-N coordination structure in CeMet enhances cerium redox cycling, facilitating efficient ROS scavenging, AMPK activation, and NF-κB suppression, thereby driving macrophage polarization toward the anti-inflammatory M2 phenotype. This immunoregulatory cascade promotes angiogenesis and osteogenesis while inhibiting excessive osteoclast differentiation, ultimately restoring balanced bone remodeling. Importantly, this functionally coordinated therapeutic progression is biologically consistent with the pathological development and healing trajectory of periodontitis. Both in vitro and in vivo studies demonstrate effective suppression of bacterial growth and inflammation, accompanied by enhanced vascularized alveolar bone regeneration, highlighting a minimally invasive and antibiotic-free therapeutic strategy for periodontitis. STATEMENT OF SIGNIFICANCE: Inflammation-driven oxidative stress and immune dysregulation represent major barriers to effective bone regeneration in periodontitis. Here, we present a multifunctional core-shell microneedle system designed to deliver biologically coordinated, spatiotemporally programmed therapy. The microneedle shell rapidly releases ZIF-8-derived Zn²⁺ to eliminate pathogenic bacteria and inhibit biofilm formation during the early infectious phase, while the core enables sustained delivery of a cerium-metformin (CeMet) coordination complex to modulate oxidative stress and immune imbalance. By coupling Ce³⁺/Ce⁴⁺ redox activity with metformin-mediated AMPK activation, CeMet suppresses NF-κB signaling, promotes M2 macrophage polarization, and establishes a pro-regenerative immune microenvironment. This temporally orchestrated antibacterial-immunoregenerative cascade closely recapitulates the biological healing sequence of periodontitis, providing a mechanistically grounded and translationally relevant strategy for inflammatory bone repair.

Tetrahydropyrido[3,4-b]indole derivatives doped poly(vinyl alcohol) films with excitation wavelength-dependent ultralong room temperature phosphorescence under ambient conditions

Eco-friendly waterborne optical adhesives suffer from simultaneously achieving high interfacial adhesion and high bulk cohesion, alongside poor hydrothermal resistance. Here, we address this challenge by introducing Zn2+ coordination into a covalently cross-linked acetoacetylated poly(vinyl alcohol) (AAPVA) network. This synergistic multinetwork─comprising dynamic metal-ligand bonds, PVA crystallites, and covalent cross-links─dissipates energy to alleviate cohesive brittleness while providing new interaction sites at the adhesive-substrate interface. Consequently, the average peel strength is remarkably enhanced from 2.68 × 10-2 to 9.32 × 10-2 N mm-1, achieving optimal hydrothermal aging resistance at 0.22 wt % Zn2+. Furthermore, quantitative topological analysis via time-resolved low-field NMR, DSC, and FT-IR reveals that Zn2+ accelerates the initial cross-linking kinetics. Notably, the network constraint sites peak at 0.10 wt % Zn2+, while crystallization is completely suppressed above 0.64 wt %. This work provides a robust physical paradigm for utilizing dynamic metal coordination to decouple the adhesion-cohesion conflict in soft materials for demanding environments.

Hydrogels are widely used in tissue engineering and scaffold fabrication due to their excellent biocompatibility, while 3D printing excels at creating complex architectures. Among various techniques, low-temperature extrusion-based 3D printing has shown promise for hydrogel scaffold fabrication, as rapid solidification under controlled cooling can improve shape retention during deposition. However, commercial low-temperature DIW systems are often expensive, closed-source, and difficult to customize. Moreover, most require a two-step post-processing workflow involving external freeze-thaw cycles, which can damage structures through mechanical disturbance and temperature gradients, increasing contamination risk. To address these issues, we developed a low-cost, open-source low-temperature 3D printing platform by modifying a commercial FDM printer with custom hardware and upgraded software. It maintains stable - 30°C ± 1°C and supports in-situ freezing and freeze-thaw processing. Using a Poly(vinyl alcohol)-lignosulfonate sodium-TEMPO-oxidized cellulose nanofibrils (PVA-LS-TOCNF) hydrogel as the model ink, we achieved stable printing of various patterns and mechanical test specimens, with tensile properties comparable to those from ex-situ freeze-thaw methods. Overall, this platform significantly lowers barriers to low-temperature hydrogel 3D printing and improves accessibility.

Microneedle (MN) patches have emerged as a highly efficient platform for localized drug delivery, showing great promise in cancer therapy due to their ability to enable precise drug administration. However, conventional MN systems are limited by the low drug-loading capacity of their tips and primarily rely on biologically inert, nontherapeutic matrices for structural support, which restricts further gains in antitumor efficacy. Herein, we present a strategy turning toxicity into therapy by constructing palladium nanoparticle-loaded poly(vinyl alcohol)/polyethylenimine (PVA/PEI@Pd) hydrogel microneedles (PPPd-MNs), which exploit the intrinsic cytotoxicity of PEI for synergistic melanoma therapy. The PPPd-MNs efficiently catalyze the deprotection of a doxorubicin prodrug (P-DOX), enabling in situ generation of active doxorubicin (DOX). Notably, the PEI matrix serves a dual function: acting as a robust ligand to stabilize Pd catalysts and functioning as a therapeutic agent that disrupts cancer cell membranes. Both in vitro and in vivo experiments demonstrate that the combination of Pd-mediated bioorthogonal activation of DOX and PEI-induced membrane damage achieves a remarkable synergistic therapeutic outcome in a murine melanoma model, resulting in a tumor inhibition rate of up to 98%. This work repurposes the inherent cytotoxicity of the carrier material as an active therapeutic component, offering a novel paradigm for the design of high-performance bioorthogonal catalytic systems.

Hydrogel adhesives that simultaneously possess high toughness, strong interfacial adhesion, and freeze resistance are urgently needed for emerging flexible electronics and wearable devices. However, conventional hydrogels typically suffer from weak bonding to diverse substrates and brittle failure under subzero conditions. Herein, we present a cation-dipole-enhanced eutectic organohydrogel (APQ-DES) constructed via an interpenetrating network strategy using a choline chloride/glycerol deep eutectic solvent (DES) as the dispersion medium. The system combines chemically cross-linked polyacrylamide (PAM), poly(vinyl alcohol) (PVA), and cationic quaternary ammonium chitosan (QCS). The DES endows the hydrogel with excellent freeze tolerance, while synergistic cation-dipole interactions between QCS and various substrates, together with hydrogen bonding from PVA and PAM, enable robust adhesion across diverse materials, including PTFE, rubber, glass, and wood, achieving lap-shear strengths up to 584.57 kPa. The optimized APQ-DES hydrogel exhibits outstanding mechanical properties (tensile strength: 206.99 kPa, elongation at break: 1891%, toughness: 1.71 MJ·m-3), maintains flexibility and ionic conductivity at -20 °C, and functions as a reliable strain sensor with rapid response (361 ms), broad sensing range (0-400% strain), and stable cyclic performance. Demonstrations of multisite human motion monitoring under cold conditions highlight its potential for winter sports training evaluation, human-machine interfaces, and low-temperature wearable healthcare applications.

Double-network hydrogel systems are developed to enhance the structural and mechanical stability of single-layer hydrogels, which are used as biological or load-bearing materials. In this work, bilayer hydrogel systems comprising polyacrylamide (PAM) and poly(vinyl alcohol) (PVA) were fabricated, followed by layer-selective reinforcement with multi-walled carbon nanotubes (CNTs) and nanodiamonds (NDs) to obtain PAM-CNT/PVA-ND and PAM-ND/PVA-CNT constructs. The experimental and theoretical analyses revealed a strong correlation between bilayer architecture, nanoscale reinforcement, and the resulting structure-property relationships. Swelling studies showed that water uptake followed a combination of Fickian and non-Fickian diffusion mechanisms, with diffusion exponents (n) ranging from 0.307 to 0.350. The swelling kinetics were well described by a pseudo-second-order model, with the swelling rate constants increasing from 0.0108 for PAM/PVA to 0.0323 for PAM-ND/PVA-CNTs, indicating faster swelling in reinforced bilayer systems. The equilibrium swelling ratio decreased from 14.15 for PAM/PVA to 6.21 for PAM-ND/PVA-CNTs, reflecting reduced water uptake due to nanoscale reinforcement. The nanocomposite bilayers exhibited significantly improved stability compared to the unreinforced PAM/PVA hydrogels. After degradation testing, the PAM-ND/PVA-CNT hydrogel retained approximately 90% of its original mass, demonstrating strong interfacial cohesion and resistance to hydrolytic degradation. Mechanical evaluation revealed that the PAM-CNT/PVA-ND bilayer achieved the highest compressive strength of 0.42 MPa, highlighting efficient stress transfer across the reinforced interface. The PAM-CNT/PVA-ND bilayer hydrogel showed the highest compressive strength and higher interfacial adhesion strength, which implies effective stress transfer across the interfaces. The synergistic effect of the reinforcement with CNTs in the load-bearing layer and nanodiamonds' contribution to the interfacial cohesion is due to this enhanced performance. Cytocompatibility studies confirmed more than 99% viability of MG-63 cells, indicating excellent biological compatibility. Consequently, enhanced stress transfer in the CNT-reinforced PAM layer, together with hydrogen-bond-mediated interfacial cohesion from nanodiamonds, governs the structure-property response of the bilayer system. These findings establish layer-selective nanoscale reinforcement in bilayer PAM-PVA hydrogels as an effective strategy to control swelling behavior, mechanical performance, biological activity, and stability for tissue engineering and regenerative medicine applications.

The development of processable adsorbent materials that combine high capacity, fast transport, and structural stability remains a key challenge for water treatment applications. Here, a dispersible ZIF-cellulose nanocrystal (ZIF-CNC) nanohybrid platform is introduced and integrated within a poly(vinyl alcohol)-carboxymethylcellulose (PVA-CMC) matrix to form architecture-tunable materials with controlled transport properties. The nanohybrid enables uniform dispersion of ZIF-8 domains while preserving accessible porosity and interfacial functionality. By varying processing routes, the same composition is reconfigured into hydrogels and cryogels, allowing decoupling of composition from structure. In the hydrogel state, NaCl conditioning promotes ion enrichment and high ionic conductivity (up to 8.3 S·m-1), while in the cryogel state, freeze casting generates a highly porous and interconnected architecture (91% porosity, 0.14 g·cm-3 density) that enhances mass transport. The freeze-cast cryogel exhibits superior adsorption performance, achieving 97.6% removal of methylene blue and a maximum Cu2+ adsorption capacity of 154.5 mg·g-1 with 89.6% removal efficiency. Adsorption follows pseudo-second-order kinetics (R2 = 0.999) and is dominated by coordination and interfacial interactions at ZIF-CNC domains. The improved pore connectivity and accessibility in freeze-cast structures reduce mass transfer limitations and enhance utilization of active sites. Practical applicability is demonstrated through seed germination assays, where treated water restores plant growth to near-reference conditions. This work highlights a scalable strategy for coupling MOF nanohybrids with architecture-directed processing to control transport and adsorption performance, providing a versatile platform for high-efficiency water treatment.

By mixing carbon nanotubes, carbon nanospheres, carborundum, or attapulgite into an ethanol system dissolved with dipentaerythritol penta-/hexa-acrylate, branched polyethylenimine, and tetradecylamine, the uncatalyzed one-step in situ reaction of a long-chain alkyl-containing polymer was produced on the above-blended matrices to construct a superhydrophobic, photothermal, nonfluorinated organic-inorganic hybrid material at room temperature. The optimal hybrid material-coated fabric had 155.0° contact angle and 2.0° sliding angle, and its surface temperature increased to 71.6 °C under irradiation (1 sun, 300 s); meanwhile, complete repellency of such a coating to 95 °C water was also reached (contact angle: 152.6°, sliding angle: 2.1°), affirming that a robust air layer, between the solid and liquid, existed in the coating product; given this, the above-mentioned coated fabric efficiently provided protective benefits, including icing delay, photothermal deicing, snow removal, hot-sewage repellency, and antimicrobial properties. Based on the substrate design idea, the poly(vinyl alcohol) sponge was used for coating with the self-manufactured anti-icing and hot sewage-repellent hybrid product to form a simple photothermal evaporator; its evaporation rates for desalinating simulated seawater and saliferous reactive textile-dyeing wastewater were 2.19 kg/m2h and 2.21 kg/m2h, respectively. Even when in contact with 95 °C acid dyeing residual liquor and 0 °C azoic dyeing residual liquor, this self-floating evaporator could achieve a remarkable purification treatment effect and always keep its Janus superwetting property. We believe that the easy preparation and performance enhancement strategy for superhydrophobic, photothermal, nonfluorinated organic-inorganic hybrid materials, based on synergy between hot-water repellency and substrate design, coincides with technology trends of cleaner production and function integration, which has important implications for exploiting wide-temperature range antiwetting, multipurpose products.

This study aimed to develop and evaluate a ternary co-encapsulation system based on electrospun poly(vinyl alcohol) (PVA) nanofibers containing Aloe vera extract, methylglyoxal (MGO), and collagen for multifunctional wound-healing applications with controlled therapeutic delivery. Electrospun nanofibers were characterized by scanning electron microscopy and FTIR spectroscopy. Swelling, degradation, and in vitro release profiles were evaluated under physiological conditions. Release kinetics were analyzed using Korsmeyer-Peppas and Weibull models. Antimicrobial activity against Escherichia coli and Staphylococcus aureus was assessed according to JIS Z 2801. Cytocompatibility was evaluated using human fibroblast cultures following ISO 10993-5 guidelines. The co-encapsulated nanofibers exhibited homogeneous morphology with fiber diameters of 350-500 nm and preserved bioactive agents´ integrity. The system showed a biphasic release profile, with rapid Aloe vera release (~80% within 4 h) followed by sustained MGO and collagen release up to 160 h. Release behavior involved coupled diffusion, polymer relaxation, and partial matrix dissolution. The ternary system demonstrated strong antimicrobial activity, achieving approximately 99.4% inhibition of E. coli, while maintaining excellent cytocompatibility with cell viability above 100%. The ternary co-encapsulation strategy synergistic antimicrobial and regenerative effects through controlled multi-agent delivery in electrospun PVA wound-dressing platforms.

Epidermolysis bullosa (EB) is a debilitating genetic disorder characterized by extreme skin fragility and chronic wound formation, often complicated by bacterial infections. Current wound dressings provide limited protection against infection and may induce cytotoxicity or mechanical trauma. Herein, we report a multifunctional nanofibrous dressing based on casein/poly(vinyl alcohol) (PVA) integrated with an aggregation-induced emission (AIE) photosensitiser (PS) for enhanced antibacterial performance. Bilayer nanofibrous mats were fabricated via multi-nozzle electrospinning, combining a mechanically robust PVA support layer with a bioactive casein-rich surface. Post-fabrication, glutaraldehyde crosslinking improved structural stability, while plasma polymerization enabled immobilization of an AIE PS (TPAQ-PF6) onto the fiber surface. The resulting materials exhibited tunable wettability, preserved nanofibrous morphology, and stable AIE fluorescence. Under light irradiation, AIE-functionalised dressings generated reactive oxygen species (ROS), leading to significant antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Fluorescence imaging confirmed enhanced ROS production at the material surface. Importantly, cytocompatibility assays using keratinocytes and fibroblasts demonstrated good cytocompatibility, highlighting suitability for potential wound-contact applications. Overall, this work presents a biocompatible, photodynamically active dressing platform that integrates natural polymers with advanced AIE technology, offering a promising strategy for infection control in fragile skin conditions such as EB.

The increasing presence of microplastics (MPs) in aqueous matrices has driven the search for efficient and sustainable technologies for their removal. In this context, this work investigates the development of green polymeric membranes based on poly-(vinyl alcohol) (PVA) reinforced with bentonite clay nanoparticles (ArNPben), aiming to establish relationships between structure, properties, and performance in microplastic filtration. The membranes were produced by the solvent evaporation phase inversion method, employing PVA at different concentrations (6-10% w/v), citric acid as a cross-linking agent, and glycerol as a plasticizer, with the incorporation of bentonite (1-5% w/w). Characterization was performed using morphological, spectroscopic, and thermal techniques (SEM, FTIR, TGA, and DSC), associated with the evaluation of transport behavior and retention efficiency. The results demonstrated that the controlled incorporation of bentonite promotes structural reorganization of the polymer matrix, directly affecting hydraulic permeability, stability, and interaction with particles. A critical dispersion limit of the inorganic phase was observed, where low concentrations favor the formation of homogeneous and functionally efficient structures, while higher concentrations induce structural heterogeneity and increased resistance to transport. The formulation containing 6% (w/v) PVA and 1% (w/w) bentonite showed the best overall performance, combining structural stability and permeation capacity, achieving an average PM removal efficiency of 99.78 ± 0.13% in tests conducted under controlled pressure. Evidence obtained by FTIR and TGA confirmed the retention of polymeric material on the surface of the membranes after use. The results highlight the potential of the developed hybrid membranes as a sustainable and technically viable alternative for application in water treatment systems contaminated by microplastics, contributing to the advancement of technologies based on materials with low environmental impact.

Currently, asymmetric polymeric membranes exhibit numerous advantages for wound dressing applications. Usually, numerous systems allow the release of only one or several antibacterial drugs to fight against the bacteria present on the wound. However, to be efficient, it is necessary to disrupt biofilm formation in order to render the enclosed bacteria sensitive to the antibacterial agent. Here, we describe a system capable of achieving such goal via a double compartment asymmetric polymeric membrane designed for dual drug release. In view of elaborating our gradient-structured membrane for differential kinetic release of combined antibiofilm/antibiotic agents in the context of wound dressing applications, a previously electrospun poly(vinyl alcohol) (PVA) fibrous membrane (EFM) was combined with a renewable poly(butylene-succinate-co-adipate) (PBSA) asymmetric porous membrane (AM) via physical adhesion. Physical adhesion was promoted via surface modification of the PVA fibers involving complexation of the numerous PVA hydroxyl groups with phenyl boronic acid (PBA). This modification resulted in heightened hydrophobicity of the upper EFM layer with substantial contact angle increase up to 115° allowing for effective adhesion of the PVA based EFM onto the AM. No delamination was observed. Thus, thanks to surface modification, a gradient-structured double compartment asymmetric membrane (DCAM) was obtained consisting of a dense/macro-/micro-/nano-porous structure. Furthermore, as proof of concept, our study shows that PBA can be used as a pro-drug mimic pH sensitive system exhibiting release profiles in aqueous environment up to 3-fold higher in acidic compared to that for neutral or alkaline environments. Moreover, the BSA (Bovine Serum Albumin) use as a potential therapeutic model protein was encapsulated within the porous structure and its release profile was monitored over time showing maximum release attained within 24 h. Finally, the biocompatibility of our new DCAM was confirmed via the internationally recognized standard ISO 10993-5: 2009 assay for the in vitro cytotoxicity testing of medical devices. Our results are promising in that they provide a new structural substrate for the dual concomitant differential-controlled release of large amounts of high (antibiofilm and potentially other therapeutic proteins) and low molecular weight (antibacterial) bioactive agents.

Degradable cellulose nanofiber/MXene composite films with low thermal conductivity for infrared stealth and photothermal conversion.

Hydrogels are highly hydrated cross-linked polymer networks whose composition and structure can be engineered to achieve desirable mechanical properties, adhesion, and biocompatibility for biomedical, functional material, and environmental applications. In this study, acrylamide (AAM) was employed as the primary backbone monomer to construct the fundamental polymer network. Methacrylated lysine (LysMA), methacrylated poly(vinyl alcohol) (PVAMA), and carboxymethyl cellulose (CMC) were incorporated as functional comonomers, while N,N'-methylenebis(acrylamide) (MBAA) served as the chemical cross-linker to establish a stable and tunable three-dimensional structure. The multiple intermolecular interactions of the amine and carboxyl groups provided by LysMA effectively enhanced interfacial adhesion. Meanwhile, PVAMA and CMC synergistically reinforced the network toughness and maintained overall mechanical integrity through hydrogen bonding and chain entanglement effects. After optimizing the compositional ratios, the hydrogel exhibited significantly enhanced mechanical performance, with the tensile stress increasing by approximately 680.2% and the toughness improving by 393.5% compared to the control group without PVAMA, indicating a markedly improved ability to withstand deformation and effectively absorb and dissipate mechanical energy. In terms of adhesion performance, the optimized hydrogel achieved a maximum adhesion strength of 213.63 kPa on aluminum substrates, which is markedly superior to most previously reported systems. Notably, the optimized formulation not only balanced high adhesion strength and enhanced mechanical performance, but also exhibited good fatigue resistance and biocompatibility, confirming its stability and safety under long-term application scenarios. These findings highlight a rational molecular design and compositional optimization strategy for developing high-performance functional hydrogels with broad cross-disciplinary application potential.

Leucine (Leu) is a promising biomarker for metabolic health and muscle growth, offering significant potential for assessing physical well-being. Sweat sensors for Leu detection eliminate the reliance on invasive blood analysis and the sophisticated, large-scale instrumentation. Current sweat sensors, however, are complex to fabricate, exhibit low sensitivity toward nonelectroactive Leu, require intense exercise or thermal/chemical stimulation to generate sweat, and lack reusability. This work reports a flexible, highly sensitive, and reusable sweat sensor based on molecularly imprinted polymers, Prussian blue nanoparticles, and laser-induced graphene. When integrated with a highly permeable porous Poly(vinyl alcohol) hydrogel for convenient and rapid collection of instantaneous sweat secreted from the fingertip, the sensor can continuously detect Leu with high sensitivity (7641 nA mm-2 per decade), low detection limit (10 nM), and excellent repeatability. This flexible biosensing patch offers a promising strategy for noninvasive sweat Leu analysis and wearable health monitoring, showing potential for assessing health status related to obesity, type 2 diabetes (T2DM), and muscle loss.

ABSTRACT Poly(vinyl alcohol) (PVA) is constrained by its low thermal resistance, high water solubility, and moderate mechanical strength, limiting its use in advanced applications. To overcome these issues, a novel, one-step bio-based modification of PVA was developed using starch, malic acid, and phthalic anhydride. The resulting biocomposite film (PVA+) is transparent, flexible, and exhibits significantly enhanced properties. Thermogravimetric analysis showed a 60°C improvement in decomposition temperature to 297.8°C. Mechanical testing revealed percent of extension increase from 262.00 ± 3.92% to 371.00 ± 6.65%, while force of strain increase from 42.000 ± 1.829 N to 54.00 ± 1.398 N. Furthermore, the film demonstrated complete insolubility in common organic solvents while maintaining 30% biodegradability over 90 days. This sustainable approach effectively enhances the performance of PVA without the use of toxic cross-linkers.