Search Results (438)

Engineered wood is increasingly valued for its use of renewable raw materials, low environmental impact, and good performance characteristics. The wide variety of raw materials used to produce engineered wood requires detailed research to select rational technological production parameters. This paper examines engineered wood produced from furniture-recycling waste and different polyurethane compositions. The factors under analysis include mixture pressure level, binder type, and filler preparation. The effect of the mixture’s pressure level on density, structure, strength, and moisture indicators was evaluated. The pressure levels were 1.5, 2.0, 2.5, 3.0, and 3.5 MPa. Tests have shown that the mixture pressure level significantly affects compressive strength, absorption, swelling, and structure formation. A rational pressure level of 3.0 MPa was determined. When using this level, there are no voids in the samples. Depending on the binder composition, the resulting compressive strength ranges from 20.5 to 25.6 MPa, water absorption from 7.62 to 10.3 kg/m², and swelling from 8.65 to 12.6%. At a pressure of 3.5 MPa, the properties of engineered wood improve further, but the binder begins to separate from the mixture. A significant influence of the binder on compressive strength, absorption, and swelling was observed. A detailed kinetic analysis was performed to evaluate changes in sample strength following production. The tests showed that the compressive strength increased markedly 14 days after sample preparation. Full article

Background/Objectives: Poly(lactic-co-glycolic acid) (PLGA) microspheres offer sustained drug delivery but often suffer from broad particle size distribution (PSD), leading to inconsistent release profiles. This study investigates wet sieving as a post-processing strategy to precisely control PSD, quantified by the Span value, and evaluates its impact on the performance of triamcinolone acetonide (TA)-loaded PLGA microspheres. Methods: Triamcinolone acetonide-loaded PLGA microspheres were prepared via emulsification-solvent evaporation. Wet sieving was employed as a post-processing strategy to obtain distinct particle size fractions and groups with defined polydispersity (Span values). The microspheres were characterized for particle size distribution, drug loading, surface morphology, and in vitro release kinetics. To establish the in vivo relevance of polydispersity control, the pharmacokinetic profiles of different Span groups were first determined using LC-MS/MS following intra-articular injection in rats. Subsequently, their therapeutic efficacy was evaluated in a rat model of knee osteoarthritis, with outcomes assessed by joint swelling measurement and histopathological analysis. Results: Microspheres were prepared, fractionated into distinct size groups (0–20, 20–28, 28–40, 40–50, >50 μm) and polydispersity groups (Span = 1.4, 0.8, 0.5). We identified Span as a dominant factor independent of mean particle size. Reducing the Span from 1.4 to 0.5 significantly decreased burst release (24.15% to 14.51%), prolonged mean residence time (MRT 88.52 to 123.53 h), and enhanced anti-inflammatory and cartilage-protective effects in a rat model of knee osteoarthritis. Conclusions: This work establishes Span ≤ 0.5 as a critical quality attribute and presents wet sieving as a simple, effective method to ensure batch-to-batch consistency and predictable in vivo performance for PLGA microsphere products. Full article

In this study, semi-interpenetrating polymer network (semi-IPN) hydrogels based on methacrylated dextran and native inulin were designed as biodegradable carriers for the colon-specific delivery of uracil as a model antitumor compound. The hydrogels were synthesized via free-radical polymerization, using diethylene glycol diacrylate (DEGDA) as a crosslinking agent at varying concentrations (5, 7.5, and 10 wt%), and their structural, thermal, and biological properties were systematically evaluated. Fourier transform infrared spectroscopy (FTIR) confirmed successful crosslinking and physical incorporation of uracil through hydrogen bonding. Concurrently, differential scanning calorimetry (DSC) revealed an increase in glass transition temperature (T_g) with increasing crosslinking density (149, 153, and 156 °C, respectively). Swelling studies demonstrated relaxation-controlled, first-order swelling kinetics under physiological conditions (pH 7.4, 37 °C) and high gel fraction values (84.75, 91.34, and 94.90%, respectively), indicating stable network formation. SEM analysis revealed that the hydrogel morphology strongly depended on crosslinking density and drug incorporation, with increasing crosslinker content leading to a more compact and wrinkled structure. Uracil loading further modified the microstructure, promoting the formation of discrete crystalline domains within the semi-IPN hydrogels, indicative of physical drug entrapment. All formulations exhibited high encapsulation efficiencies (>86%), which increased with increasing crosslinker content, consistent with the observed gel fraction values. Simulated in vitro gastrointestinal digestion showed negligible drug release under gastric conditions and controlled release in the intestinal phase, primarily governed by crosslinking density. Antimicrobial assessment against Escherichia coli and Staphylococcus epidermidis, used as an initial or indirect indicator of cytotoxic potential, revealed no inhibitory activity, suggesting low biological reactivity at the screening level. Overall, the results indicate that DEGDA-crosslinked dextran/inulin semi-interpenetrating (semi-IPN) hydrogels represent promising carriers for colon-targeted antitumor drug delivery. Full article

Dextrin-based nanosponges (D-NS) are promising candidates for oral drug delivery due to their biocompatibility, mucoadhesive properties, and tunable swelling behavior. In this study, pH-sensitive nanosponges were synthesized using β-cyclodextrin (β-CD), GluciDex^®2 (GLU2), and KLEPTOSE^® Linecaps (LC) as building blocks, crosslinked with pyromellitic dianhydride (PMDA) and citric acid (CA). The nanosponges were mechanically size-reduced via homogenization and ball milling, and characterized by FTIR, TGA, dynamic light scattering (DLS), and zeta potential measurements. Swelling kinetics, cross-linking density (determined using Flory–Rehner theory), rheological behavior, and mucoadhesion were evaluated under simulated gastric and intestinal conditions. The β-CD:PMDA 1:4 NS was selected for drug studies due to its optimal balance of structural stability, swelling capacity (~863% at pH 6.8), and highest apomorphine (APO) loading (8.23%) with 90.58% encapsulation efficiency. All nanosuspensions showed favorable polydispersity index values (0.11–0.30), homogeneous size distribution, and stable zeta potentials, confirming suspension stability. Storage at 4 °C for six months revealed no changes in physicochemical properties or apomorphine (APO) degradation, indicating protection by the nanosponge matrix. D-NS exhibited tunable swelling, pH-responsive behavior, and mucoadhesive properties, with nanoparticle–mucin interactions quantified by the rheological synergism parameter (∆G′ = 53.45, ∆G″ = −36.26 at pH 6.8). In vitro release studies demonstrated slow, sustained release of APO from D-NS in simulated intestinal fluid compared to free drug diffusion, highlighting the potential of D-NS as pH-responsive, mucoadhesive carriers with controlled drug release and defined nanoparticle–mucin interactions. Full article

Controlled-release systems must translate material design choices into predictable pharmacokinetic (PK) profiles, yet purely mechanistic or purely data-driven models often underperform when tuning complex polymer networks. Here, we develop tunable poly(vinyl formal) membranes (PVFMs) for diclofenac delivery and integrate classical kinetic analysis with a Generalized Regression Neural Network (GRNN) to connect formulation variables to release behavior and PK-relevant targets. PVFMs were synthesized across a gradient of crosslink densities by varying HCl content; diclofenac release was quantified under standardized conditions with geometry and dosing rigorously controlled (thickness, effective area, surface-area-to-volume ratio, and areal drug loading are reported to ensure reproducibility). Release profiles were fitted to Korsmeyer–Peppas, zero-order, first-order, Higuchi, and hyperbolic tangent models, while a GRNN was trained on material descriptors and time to predict cumulative release and flux, including out-of-sample conditions. Increasing crosslink density monotonically reduced swelling, areal release rate, and overall release efficiency (strong linear trends; r ≈ 0.99) and shifted transport from anomalous to Super Case II at the highest crosslinking. Classical models captured regime transitions but did not sustain high accuracy across the full design space; in contrast, the GRNN delivered superior predictive performance and generalized to conditions absent from training, enabling accurate interpolation/extrapolation of release trajectories. Beyond prior work, we provide a material-to-PK design map in which crosslinking, porosity/tortuosity, and hydrophobicity act as explicit “knobs” to shape burst, flux, and near-zero-order behavior, and we introduce a hybrid framework where mechanistic models guide interpretation while GRNN supplies robust, data-driven prediction for formulation selection. This integrated PVFM–GRNN approach supports rational design and quality control of controlled-release devices for diclofenac and is extendable to other therapeutics given appropriate descriptors and training data. Full article

The effect of mixed soy and whey protein in the matrix on properties and digestion characteristics of emulsion-filled gels was investigated. Different matrix protein concentrations (8–14%) with a composite soy and whey protein (SW) ratio of 5:5 were screened using gel hardness. The better-performing gel (13%) was selected for matrix composition studies. Soy and whey composite protein mixed at different ratios (S/W = 0/10, 3/7, 5/5, 7/3, and 10/0) was dispersed into another soy-whey (S/W = 6/4) composite emulsion and gelled thermally. Different hybrid protein ratios in the matrix can alter the textural and rheological properties and, consequently, the digestion kinetics of mixed plant-animal gel systems. The storage modulus was highest at an S/W ratio of 0/10. The hardness of gel with the S/W ratio matrix of 0/10 was 3.10 and 9.60 times higher than that of 5/5 and 10/0 (p < 0.05). The SW ratio did not affect water-holding capacity or springiness (p > 0.05). All the gels had swelling ability below 10% except SW 10/0 (around 60%). Gels with an S/W of 5/5 exhibited a lower hydrolysis degree and rate during gastric digestion, while the reverse occurred during intestinal digestion. The compact gel network might limit pepsin’s accessibility to cleavage sites. Full article

Poly(ethylene glycol) (PEG) and poly(2-hydroxy ethyl methacrylate) are polymers used for many biomedical applications due to their biocompatibility, non-toxicity, and antibiofouling properties. In this work, a new comb-like hydrogel based on 2-hydroxyethyl methacrylate (HEMA) grafted onto a polyethylene glycol network (net-PEG) was synthesized by gamma radiation from Co⁶⁰ in two steps. First, PEG (Mw = 20,000) was crosslinked at 30 kGy, and then HEMA was grafted, varying the concentration (5–20% v/v) and irradiation dose (2.5–15 kGy). Results of infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the incorporation of HEMA onto net-PEG. Moreover, the properties of comb-like hydrogel (net-PEG)-g-HEMA were studied through swelling kinetics, drug loading and release, antimicrobial activity, and biocompatibility assays. The findings showed a different behavior in swelling kinetics and drug delivery depending on HEMA grafting. Comb-like hydrogel with 30 and 66% grafting could load more ciprofloxacin (2 mg g⁻¹) than net-PEG (1.5 mg g⁻¹) but only release 38 and 48% at 24 h, respectively. In addition, all drug-loaded hydrogels displayed inhibition for Gram-negative bacteria (E. coli) and a cell viability superior of 95% using mouse embryonic fibroblasts (BALT/T3). Comb-like hydrogel has potential application in the biomedical field such as in wound dressings or controlled drug delivery systems. Full article

The stability of physical and mechanical properties of highly filled swelling rubbers in polar and nonpolar liquids (oil, mineralized water) was studied. Nitrile butadiene rubber of BNKS-28 AMN grade served as the elastomer matrix, with sodium salt of carboxymethylcellulose (NaCMC) as the swelling filler. Oxal T-92, a mixture of dioxane alcohols (10–50 phr, step 10 phr), was used as a plasticizer due to its good thermodynamic miscibility with rubber (confirmed by Scatchard–Hildebrand calculations). Adding Oxal T-92 to NaCMC-filled compounds markedly reduced Mooney viscosity, improving processing through increased macromolecule mobility, without significantly affecting vulcanization kinetics—indicating chemical inertness toward crosslinking centers. Increasing Oxal T-92 from 10 to 50 phr reduced tensile strength from 4.1 MPa to 2.9 MPa. Swelling in aqueous solutions of varying mineralization was evaluated via volume and mass change. The optimal plasticizer content for high swelling with acceptable strength is 20–30 phr. After 3 days in oil and formation water, NaCMC-filled rubbers retained stable physical and mechanical properties. Full article

Temperature-responsive hydrogels are sophisticated stimuli-responsive biomaterials that undergo rapid, reversible sol–gel phase transitions in response to subtle thermal stimuli, most notably around physiological temperature. This inherent thermosensitivity enables non-invasive, precise spatiotemporal control of material properties and bioactive payload release, rendering them highly promising for advanced biomedical applications. This review critically surveys recent advances in the design, synthesis, and translational potential of thermo-responsive hydrogels, emphasizing nanoscale and hybrid architectures optimized for superior tunability and biological performance. Foundational systems remain dominated by poly(N-isopropylacrylamide) (PNIPAAm), which exhibits a sharp lower critical solution temperature near 32 °C, alongside Pluronic/Poloxamer triblock copolymers and thermosensitive cellulose derivatives. Contemporary developments increasingly exploit biohybrid and nanocomposite strategies that incorporate natural polymers such as chitosan, gelatin, or hyaluronic acid with synthetic thermo-responsive segments, yielding materials with markedly enhanced mechanical robustness, biocompatibility, and physiologically relevant transition behavior. Cross-linking methodologies—encompassing covalent chemical approaches, dynamic physical interactions, and radiation-induced polymerization are rigorously assessed for their effects on network topology, swelling/deswelling kinetics, pore structure, and degradation characteristics. Prominent applications include on-demand drug and gene delivery, injectable in situ gelling systems, three-dimensional matrices for cell encapsulation and organoid culture, tissue engineering scaffolds, self-healing wound dressings, and responsive biosensing platforms. The integration of multi-stimuli orthogonality, nanotechnology, and artificial intelligence-guided materials discovery is anticipated to deliver fully programmable, patient-specific hydrogels, establishing them as pivotal enabling technologies in precision and regenerative medicine. Full article

Fungal infections caused by Fusarium solani demand sustainable alternatives to conventional fungicides and free nanoparticles, which often show poor stability and rapid release. This study developed zinc-crosslinked alginate microparticles containing silver (AgNPs), zinc oxide (ZnONPs), or both to improve nanoparticle stability, sustain release, and enhance antifungal efficacy. Microparticles were produced by ionic gelation and characterized by FTIR, microscopy, swelling analysis, encapsulation efficiency, and kinetic modeling. AgNPs weakened hydrogen bonding within alginate, yielding rough, porous structures, whereas ZnONPs strengthened COO⁻–Zn²⁺ interactions, forming smoother surfaces with smaller pores; co-loaded particles combined both characteristics. Encapsulation efficiencies were 77.9% (AgNPs) and 98.6% (ZnONPs), with co-loaded systems retaining 64.0% and 98.9%, respectively. Swelling was highest in AgNP-loaded microparticles (63.8%) and lowest in ZnONP and co-loaded systems (≈42%). AgNPs followed anomalous transport (n = 0.65), while ZnONPs transitioned from Fickian diffusion (n ≈ 0.36–0.38) to zero-order release (K₀ = 1.00 for ZnONPs alone; 0.80 co-loaded). Antifungal tests showed strong inhibition: 80.7% for AgNPs, 91.4% for ZnONPs, and 99.7% for co-loaded formulations. Microscopy confirmed membrane disruption, hyphal collapse, and ROS-mediated damage, with the strongest effects in co-loaded samples. These results demonstrate a tunable, synergistic, sustained-release platform that outperforms single nanoparticles and offers a promising strategy for sustainable crop protection. Full article

This study investigates the influence of epichlorohydrin (EPCH) concentration on the rheological, mechanical, and swelling properties of lignin/PVA hydrogels. Hydrogels were prepared with EPCH concentrations ranging from 2.5% to 7.5%, and their viscoelastic properties were characterized through oscillatory strain and frequency sweep rheology. Increasing the EPCH concentration led to a substantial rise in mechanical stiffness, with the compressive modulus increasing from 21 kPa (2.5%) to 275 kPa (7.5%), accompanied by a marked reduction in swelling capacity from 460% to 190%. This behavior is attributed to the formation of a denser and more interconnected network structure with increasing cross-linking density. Furthermore, a strong correlation was observed between EPCH concentration and gelation kinetics, with higher concentrations generally leading to faster gelation times. In all formulations, gel time consistently decreased as the temperature increased from 10 to 50 °C. The optimal EPCH concentration for achieving a balance between mechanical properties and processability was determined to be 3.5%. At this concentration, the hydrogels exhibited a favorable combination of mechanical strength, shape recovery, and processability, while maintaining desirable swelling behavior. These findings provide valuable insights into the critical role of cross-linking density in determining the physicochemical properties of lignin/PVA hydrogels, paving the way for the development of these bio-based materials with tailored properties for diverse applications. Full article

Biopolymer hydrogels are attractive matrices for localised enzyme and drug delivery owing to their intrinsic biocompatibility, biodegradability, and controlled release capacity. In this study, κ-carrageenan hydrogels were engineered as enzyme-delivery systems by reinforcing the matrix with cellulose nanocrystals (CNC) or chitin nanowhiskers (ChNW) and loading bromelain as a model enzyme. The objective was to evaluate how nanofiller chemistry and morphology influence network structure and release behaviour. Parallel fabrication under identical conditions enabled a direct CNC-ChNW comparison. CNC reinforcement compacted the network and reduced swelling, whereas ChNW produced more hydrated and open architectures. Both fillers enhanced surface wettability, while their concentration modulated bulk hydration and diffusivity. Bromelain release over 24 h followed diffusion-controlled kinetics, tunable by filler type and loading. Quantitative topography and pore-size mapping supported structure–function correlations between morphology and transport. All hydrogels were bio-based, biodegradable, and fully cytocompatible, highlighting their suitability for sustainable biomedical applications. Overall, this work provides a quantitative structure-property-function framework for designing enzyme-active κ-carrageenan systems for tunable bromelain release and related biomedical applications. Full article

This study presents a novel structural modification strategy for lignin, utilizing a ternary eutectic solvent system (TESS), which induces targeted derivatization. The resulting lignin-based functional hydrogel (LBFH), prepared via rational cross-linking of derivatized lignin precursors, exhibits exceptional hygroscopic properties, with a water swelling ratio of 934.0%. Water absorption kinetics were subjected to rigorous analysis through the employment of a dual-modeling strategy that incorporates Schott kinetics and Fickian diffusion mechanisms, thereby elucidating the synergistic dynamic processes underlying surface adsorption and matrix penetration. Remarkably, LBFH maintains 48.6% water retention capacity after 7 days atmospheric exposure (25 °C, 60% RH), demonstrating unprecedented environmental stability among biopolymer hydrogels. The engineered properties of LBFH suggest its potential application in sustainable agricultural practices as drought-resistant soil amendments, and in environmental remediation as contaminant-adsorptive matrices. Full article

Alginate and chitosan (Ag/Cs) combined form an effective platform to develop biocompatible hydrogels with customizable properties for controlled drug release. Cannabidiol (CBD), a hydrophobic compound with anti-inflammatory and antibacterial effects, represents a powerful strategy to enhance their therapeutic performance. A/Cs hydrogels were produced using the CELLINK^® printer with 12 and 24 mg/mL of CBD. SEM and FTIR were assessed. Viscoelasticity was assessed using oscillatory rheology. Structural strength was evaluated via uniaxial compression. Swelling and absorption were measured gravimetrically under physiological conditions. CBD was successfully incorporated into the 3D-printed A/Cs hydrogel. Increasing the CBD concentration led to mechanical changes such as a dose-dependent decrease in G′ and a slight reduction in the linearity threshold (typically 10–30% from medium loads), while still maintaining G′ > G″. FTIR showed shifts in O–H/N–H and C=O, indicating hydrogen bonding without new reactive bands. Microscopic images revealed moderate pore compaction and increased tortuosity with dose. At higher CBD concentrations, the hydrogel resisted compression but could deform further before failure. Equilibrium swelling and absorption kinetics decreased with increasing dose, resulting in a reduced initial burst and lower water uptake capacity. The CBD-loaded hydrogel provides a mechanically suitable and molecularly stable platform for local drug release in the oral cavity. Full article

Bacterial exopolysaccharides have emerged as versatile biopolymers for the design of advanced hydrogels with adjustable physico-chemical, mechanical, and biological properties. Among these, levan, a fructose-based exopolysaccharide synthesized by various microbial species, has attracted increasing attention due to its unique structural features, high biocompatibility, and inherent bioactivity. This review provides a comprehensive overview of hydrogel systems derived from bacterial exopolysaccharides, with a particular focus on levan-based hydrogels. We discuss the molecular structure, synthesis pathways, and physico-chemical characteristics of levan that underpin its hydrogel-forming ability. Emphasis is placed on design strategies, including chemical modification, crosslinking approaches, and composite formation, that enable fine-tuning of mechanical strength, swelling behavior, and degradation kinetics. This review further highlights biomedical applications of levan-based hydrogels, encompassing drug delivery, wound healing, rejuvenation, tissue engineering, regenerative medicine, and bioprinting, while addressing current limitations and future research directions. By elucidating the structure–function relationships and emerging fabrication methodologies, this review underscores the biomedical promise of levan as a sustainable and functional biopolymer for next-generation hydrogel technologies. Full article