Search Results (504)

In this study, alginate hydrogels (A) cross-linked with a mixture of calcium and europium ions (Ca+Eu)A were developed for the first time as potential carriers for the targeted delivery and sustained release of drugs to specific regions of the gastrointestinal tract. Comparative studies were conducted to investigate the effect of the cross-linking agent (Ca²⁺, Eu³⁺, or their mixture) on the physicochemical properties of alginate hydrogels and the release kinetics of metronidazole in media simulating different gastrointestinal environments. Rheological analysis demonstrated that (Ca+Eu)A hydrogels form mechanically robust, highly cross-linked networks. The hydrogels exhibited negligible swelling in an acidic medium (swelling ratio, SR ≈ 1–1.5 g/g); however, in PBS, calcium alginate (CaA) hydrogels swelled 7–8 times more (SR ≈ 42.5 g/g) than hydrogels cross-linked with Eu³⁺ ions or a Ca²⁺/Eu³⁺ mixture (SR = 5–8 g/g). Metronidazole was released 1.5–2 times faster from calcium-cross-linked hydrogels than from hydrogels cross-linked with Eu³⁺ ions or the mixed Ca²⁺/Eu³⁺ system, whereas (Ca+Eu)A hydrogels exhibited a more sustained and uniform release profile. These results demonstrate that the drug release kinetics can be tuned by adjusting the Ca²⁺/Eu³⁺ ratio during alginate cross-linking. Consequently, such hydrogels represent a promising platform for the targeted delivery and controlled release of therapeutic agents, particularly antibiotics, to specific regions of the gastrointestinal tract. Full article

This study reports a comparative evaluation of natural polymeric biomaterial films impregnated with silver nanoparticles (AgNPs) synthesized using the ethyl acetate (EA) extract of Centratherum anthelminticum (CA), yielding CA-EA extract-mediated AgNPs (CA-EA-AgNPs). The biopolymeric films were solution cast and confirmed for nanoparticle impregnation using techniques such as FTIR, XRD, and FESEM-EDAX. In addition to possessing antimicrobial activity, AgNPs also act as structural modifiers. AgNPs significantly enhanced tensile strength from 19.00 ± 0.62 MPa to 24.52 ± 0.97 MPa and Young’s modulus from 106.2 ± 18.2 MPa to 143.8 ± 7.15 MPa for chitosan (CH)-based films. For agar (AA)-based films, tensile strength increased modestly from 105.31 ± 1.18 MPa to 111.81 ± 1.78 MPa, maintaining a high Young’s modulus (1411.8 MPa). The water contact angle changed from 31.5° to 49.9° and from 56.9° to 86.7° for CH and AA films, respectively. The nanocomposite films demonstrated controlled equilibrium swelling kinetics without structural disintegration. The films exhibited moderately improved antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis, yielding zones of inhibition (diameter) from 7.67 ± 0.47 mm to 10.33 ± 0.47 mm, 7.33 ± 0.47 mm to 9.67 ± 0.47 mm, and 7.67 ± 0.47 mm to 8.67 ± 0.47 mm for chitosan-based films and from 7.67 ± 0.47 mm to 11.67 ± 0.47 mm, 7.67 ± 0.47 mm to 10.67 ± 0.47 mm, and 7.33 ± 0.47 mm to 8.67 ± 0.47 mm for agar-based films, respectively, against their respective controls. The above findings demonstrate the potential of these nanoparticle-loaded biopolymer films as potent antimicrobial biomaterials for prospective wound management applications. Full article

Breast cancer treatment still faces challenges including local recurrence, systemic toxicity, tumor heterogeneity, drug resistance, and immunosuppression. Conventional systemic administration provides limited exposure at the tumor site and exhibits significant toxicity. Injectable hydrogels, combining the properties of minimally invasive administration, in situ gelation, local retention, and sustained release, have become a key platform for local precision drug delivery. Compared with nanomedicines or free drugs, hydrogels can both prolong drug retention time and achieve on-demand release through the modulation of crosslinking density, degradation rate, and responsive chemical bonds. This review is organized around the material logic of such systems. Injectable hydrogels are first classified into natural, synthetic, hybrid, supramolecular, nanocomposite, and self-healing systems, the in situ gelation chemistries available to each are compared, and network parameters such as crosslinking density, mesh size, swelling, porosity, modulus, and rheology are related to release kinetics and intratumoral retention. Current research is primarily advancing along two directions: one is the construction of pH-, enzyme-, redox/ROS-, hypoxia-, ATP-, glucose-or thermo-responsive hydrogels; the other is achieving active targeting by integrating functionalized hydrogels with targets such as CD44, folate receptor, integrins, EGFR, transferrin receptor, and HER2 or with biomimetic cell-membrane coatings. On this basis, hydrogels have been extended to cancer vaccines, immune checkpoint modulation, local delivery of CAR-T/CAR-NK, as well as combination therapies involving chemotherapy, photothermal therapy, photodynamic therapy, chemodynamic therapy, sonodynamic therapy, radiosensitization, gene therapy, and theranostics. The constraints imposed on hydrogel design by different payload classes, including small molecules, natural products, proteins and peptides, nucleic acids, antibodies, exosomes, and gene-editing machinery, are further examined, and imaging-integrated theranostic gels are discussed together with the emerging role of machine learning and digital fabrication in hydrogel optimization. Based on the biological foundations of breast cancer, this review summarizes advances in the material design, microenvironment-responsive release, targeting strategies, immunomodulation, and combination therapy of hydrogels, critically evaluates the limitations of each strategy, and aims to provide a reference for the design of mechanistically well-defined and translatable hydrogel delivery systems for breast cancer. Full article

Ammonia-responsive gelatin-based composite films containing cobalt metal–organic frameworks (Co–MOFs) synthesized using gallic acid as an organic ligand were developed and evaluated as intelligent packaging materials. Co–MOFs were incorporated into gelatin films at concentrations of 2.5, 5.0, 7.5, and 10.0% (w/w, based on gelatin). The effects of Co–MOF incorporation on the physicochemical, structural, thermal, mechanical, and sensing properties of gelatin films were systematically investigated. Increasing Co–MOF content reduced film moisture content (from 14.47 to 13.25–13.58%) and swelling capacity (from 599.37 to 484.88–547.30%), while increasing solubility (from 39.09 to 48.88%), water vapor permeability (WVP; from 1.652 to 2.054 g·mm/m²·h·kPa), and moisture sorption behavior. Sorption isotherm analyses based on the Guggenheim–Anderson–de Boer (GAB) and Brunauer–Emmett–Teller (BET) models confirmed enhanced water adsorption capacity and increased specific surface area in the films (from 356.13 to 455.74 m²/g). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analyses demonstrated successful incorporation of Co–MOFs into the gelatin matrix, revealing good dispersion at low and moderate concentrations and partial aggregation at higher loadings. The incorporation of Co–MOFs improved the thermal stability of the films, while only a moderate reduction in mechanical strength was observed with increasing filler content. The composite films exhibited rapid and concentration-dependent colorimetric responses toward ammonia vapor. After 120 min of exposure, the color difference (ΔE) increased from less than 1 in the control film to approximately 12, 15, 24, and 27 for G/Co–MOF2.5, G/Co–MOF5, G/Co–MOF7.5, and G/Co–MOF10 films, respectively. Films containing higher amounts of Co–MOF showed faster response kinetics and greater color differences, enabling clear visual detection of ammonia. These findings demonstrate that gelatin/Co–MOF composite films based on gallic acid-derived metal–organic frameworks are promising intelligent packaging materials for monitoring food freshness and spoilage through ammonia detection. Full article

Drying is a critical post-fermentation process because it influences product stability and the retention of bioactive compounds. The present study evaluated the effects of different drying techniques on the physicochemical characteristics, functional properties, bioactive compounds, and antioxidant activities of SCOBY-fermented pomelo peel substrate powders. Pomelo peel substrates fermented with 6% (w/w) SCOBY inoculum for 25 days were subjected to freeze drying (FD), hot-air drying (HAD; 50, 70, and 90 °C), and radio-frequency drying (RFD; electrode distances of 14, 15, and 16 cm). Drying kinetics, effective moisture diffusivity (D_eff), water activity, color, particle size distribution, functional properties, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities were determined. RFD showed comparable or slightly higher moisture diffusivity (1.19–2.06 × 10⁻⁹ m²/s) compared with HAD (1.03–1.95 × 10⁻⁹ m²/s) under suitable drying conditions, suggesting that radio-frequency heating effectively promoted internal moisture migration through volumetric dielectric heating. FD retained the highest antioxidant activity, with DPPH radical scavenging activity of 74.25% and TEAC of 24.85 μmol TE/g. However, moderate thermal treatments enhanced phenolic extractability, and HAD at 50 °C showed the highest TPC (161.65 mg gallic acid equivalents (GAE)/g DW). Among the RFD treatments, RFD at 15 cm exhibited the highest TFC (27.18 mg rutin equivalents (RE)/g DW) and maintained relatively high antioxidant capacity. FD powders showed superior water solubility and swelling capacity, whereas RFD produced finer particle distributions and improved drying efficiency. These findings demonstrate that drying techniques significantly influence the quality attributes of SCOBY-fermented pomelo substrate powders, and RFD represents a promising alternative drying technology for balancing drying efficiency and bioactive compound retention. Full article

Background/Objectives: Conventional SeDeM-ODT screening relies on physicochemical properties and endpoint disintegration tests, which may have limited discriminatory power among formulations that already meet pharmacopoeial disintegration requirements. This study aimed to extend SeDeM-ODT by incorporating texture analyzer-derived descriptors of low-volume liquid disintegration behavior. Methods: Bisoprolol fumarate was used as a low-dose model drug. Selected excipients were characterized using SeDeM and conventional SeDeM-ODT approaches. Texture analyzer distance–time profiles were used to derive swelling efficiency (SE), residue height (RH), and structural transition efficiency (STE), which were converted into SeDeM-compatible parameters. Orodispersible tablets were developed using a two-factor central composite design and evaluated for mechanical properties, pharmacopoeial disintegration, comparative dissolution performance, texture analyzer behavior, and supportive Heckel parameters. Results: All formulations met the pharmacopoeial disintegration criteria and showed rapid drug release under the applied dissolution conditions. Conventional endpoint-based responses showed limited discriminatory value within the investigated formulation space. In contrast, SE, RH, and STE differentiated formulation-dependent swelling, residual structural persistence, and transition toward structural collapse under low-volume liquid controlled-force conditions. MCC-rich formulations generally retained greater residual structure, whereas lactose-rich and/or higher-superdisintegrant formulations showed lower residual persistence. Comparative kinetic fitting and Heckel analysis supported these interpretations but did not independently establish a definitive disintegration mechanism. Conclusions: Incorporating low-volume liquid texture analyzer-derived parameters into SeDeM-ODT improved the comparative interpretation of excipient and formulation behavior. These findings suggest that pharmacopoeial disintegration compliance may coexist with distinct structural pathways not fully captured by conventional endpoints. Full article

Conventional synthetic meshes for pelvic organ prolapse (POP) frequently cause severe complications, such as tissue erosion, due to a profound mechanical mismatch with native tissue. This study proposes a novel biphasic composite scaffold combining a load-bearing melt electrowritten (MEW) polycaprolactone (PCL) framework with a compliant alginate–gelatin (Alg-Gel) hydrogel matrix. PCL meshes (1.5 and 2.0 mm pores) were infiltrated with varying Alg-Gel ratios (4:3 and 5:2) and structurally evaluated through mechanical testing, swelling/degradation assays in a simulated acidic vaginal environment (pH 4.3), and finite element analysis (FEA). Results demonstrated that the 1.5 mm PCL architecture provides a robust baseline to withstand physiological loads. Notably, the hydrogel matrix provides a viscoelastic damping effect that synergistically improves the overall mechanical stability of the composite. Furthermore, FEA accurately predicted the non-linear macroscopic response of the composite constructs. Modulating the Alg-Gel ratio also enabled precise tuning of swelling capacity (up to 1400%) and degradation kinetics. Ultimately, this biomimetic system offers a highly adaptable, tissue-like protective cushion with enhanced dynamic stability, presenting a versatile platform for future in vivovalidation. Full article

Hydrogel fibers provide a one-dimensional platform for constructing soft robotic materials that combine tissue-like compliance, high water content, structural anisotropy, and stimulus responsiveness. Compared with bulk hydrogels, their reduced radial dimensions shorten mass-transport pathways, while programmable fiber architectures convert otherwise isotropic swelling or contraction into directional deformation. This review summarizes the recent progress in anisotropic hydrogel fibers for soft robotics, with emphasis on the relationships among fabrication strategies, fiber architectures, actuation mechanisms, and robotic functions. Representative architectures, including Janus, bilayer, core–sheath, hollow, helically twisted, gradient, axially patterned, woven, and printed systems, are discussed in terms of their strain-conversion mechanisms, structural advantages, limitations, and suitable applications. Major fabrication approaches and stimulus-responsive mechanisms are further compared with respect to structural programmability, response kinetics, mechanical output, cyclic stability, scalability, and device integration. Particular attention is given to architecture selection, long-term environmental stability, interference from secondary stimuli, and the transition from laboratory demonstrations to practical soft robotic systems. Finally, key design principles and future directions are outlined for developing faster, more durable, manufacturable, and autonomous hydrogel-fiber-based soft robots. Full article

The growing demand for sustainable, biocompatible, and non-toxic biomaterials has driven significant advancements in biobased gels for biomedical applications. Among these, cellulose—the most abundant renewable biopolymer—presents an ideal platform due to its inherent hydrophilicity, structural tunability, and biodegradability. This review reports the recent advancements in the processing and engineering of cellulose-based hydrogels for drug delivery systems. We systematically explore the primary synthesis routes, including physical, chemical, and hybrid cross-linking strategies. Special emphasis is placed on chemical modifications (e.g., sulfation, carboxylation, etherification, and polymer grafting) that allow precise tuning of the gel’s mechanical strength, swelling kinetics, and stimuli-responsiveness (such as pH, temperature, or enzyme sensitivity). Furthermore, the review highlights essential characterization techniques—spanning structural, morphological, and rheological evaluations—used to relate cross-link density to the water-holding capacity and network homogeneity. By leveraging their highly hydrated and porous 3D architectures, these modified cellulosic networks demonstrate exceptional efficiency in drug loading, controlled release, and targeted localized therapy. Finally, we discuss current challenges, including industrial scalability and mechanical stability, and provide future perspectives on integrating nanoparticles and bioactive moieties to develop “smart” drug-eluting matrices and wound care dressings. Ultimately, this review underscores the immense potential of cellulose-based gels in advancing both clinical outcomes and circular economy goals. Full article

Pathological states associated with metabolic stress, such as traumatic brain injury (TBI), hypoxia, ischemic stroke, and migraine, are considered elevated risk factors for developing Alzheimer’s disease (AD). However, the mechanism underlying the effect of these conditions on the progression of AD remains largely unknown. Here, we determine how metabolic stress associated with spreading depolarization (SD)—a hallmark of stroke, hypoxia, TBI, and migraine—modulates amyloid β (Aβ42) aggregation kinetics through dynamic changes in extracellular space (ECS). To achieve this, we used ThT fluorescence to determine how the formation of different Aβ42 aggregate species depends on Aβ42 concentrations. Based on this input, we build a multiscale computational framework that integrates volume regulation, including its dependence on neuronal ion homeostasis, and Aβ42 aggregation kinetics. Our model predicts that neuronal swelling during SD accelerates aggregation, where the impact of metabolic stress is highly dependent on the timing relative to aggregation progression and the initial monomer concentration. At low monomer concentrations, early SD events promote off-pathway oligomer formation, while at higher concentrations they rapidly drive fibril formation to saturation. In the absence of mature fibrils, recurrent metabolic stress events further amplify oligomer accumulation, whereas pre-existing fibril nuclei suppress oligomer formation at the expense of fibril nucleation and growth. Increasing the intensity of metabolic stress prolongs ECS shrinkage and enhances oligomer formation. These findings reveal a mechanistic link between SD-induced microenvironmental changes and Aβ aggregation dynamics, providing a quantitative framework for understanding how acute brain injury and metabolic stress may contribute to early AD pathogenesis. Full article

Background: Oromucosal films are thin polymeric dosage forms designed to hydrate rapidly in the oral cavity and enable local or systemic drug delivery. Their performance depends on coupled processes including wetting, swelling, polymer relaxation, matrix softening, and structural failure. Because these phenomena depend strongly on the formulation composition and polymer-network organization, a mechanistic framework linking conventional characterization data to film performance is needed. This study aimed to develop a Madelung-type multifractal swelling–disintegration–release-readiness model for chitosan/hydroxypropyl methylcellulose (HPMC) films and to examine its relevance using a twelve-formulation experimental series. Methods: Twelve films based on chitosan (film-forming polysaccharide), HPMC K-4M (hydrophilic swelling polymer), glycerin (plasticizer), and starch (disintegrant) were prepared via solvent casting. The films were characterized for loss on drying, surface pH, mass and thickness uniformity, wetting time, swelling behavior, structural-disintegration onset, elongation response, rupture resistance, folding endurance, and surface roughness. The proposed model described water uptake, swelling-front motion, matrix integrity, local release-readiness activation, and hydration-induced loading as coupled fields across the film thickness. Results: Formulation markedly influenced hydration behavior, mechanical performance, structural stability, and surface morphology. Films F2 and F7 emerged as the most promising complementary unloaded matrix platforms for future active-compound incorporation and experimental release evaluation. F2 behaved as a high-swelling, mechanically stable starch-free matrix, whereas F7 combined faster wetting, starch-assisted structural destabilization, and favorable flexibility. Conclusions: This framework provides a quantitative link between empirical film characterization and formulation-level mechanistic interpretation. It translates conventional characterization parameters into descriptors related to the apparent water penetration, swelling capacity, matrix-failure tendency, mechanical suitability, and structural heterogeneity. The present results support candidate selection for future Active Pharmaceutical Ingredient-loaded studies but do not constitute validation of drug-release kinetics. Full article

Molecularly imprinted membranes (MIMs) have demonstrated tremendous potential in the field of high-efficiency separation due to their specific molecular recognition capabilities. This review aims to elucidate the underlying mechanisms governing MIMs’ performance and, moving beyond traditional classification frameworks, systematically reconstructs the classification system for MIMs from the perspectives of the spatial distribution of imprinted sites, the chemical topology of the matrix, and mass transfer kinetics. The article focuses on the decisive influence of key physical parameters such as pore size, specific surface area, hydrophilicity/hydrophobicity, and swellability on separation efficiency. It provides an in-depth analysis of the spatial matching between pore size and target molecules, the nonlinear relationship between specific surface area and adsorption capacity, and the mechanisms by which mechanical strength and swelling behavior constrain the long-term stability of the membranes. Addressing the common bottlenecks faced by MIMs “high mass transfer resistance and poor accessibility of recognition sites” this paper critically summarizes cutting-edge morphological optimization strategies, such as multi-level pore construction, nanocomposite reinforcement, and surface topological engineering, aiming to elucidate how microstructural regulation can achieve a synergistic enhancement of both high throughput and high selectivity. Finally, by reviewing breakthroughs in MIMs applications for biomedical extraction and environmental pollutant remediation, this review not only clarifies the principles governing material suitability across different scenarios but also provides a systematic technical reference for the development of next-generation, high-performance, industrial-scale MIMs. Full article

This work analyzes protocol-dependent effects on the colloidal characterization and drug loading/release analysis of model thermosensitive PNIPAM-co-COOH microgels and shows how they can be quantified or minimized through targeted methodological refinements. Findings reveal that standard single-beam DLS underestimates the collapsed hydrodynamic radius by 18% at 43 °C due to thermal convection. After drift correction, 3D-DLS combined with SLS provides a consistent description of thermally induced collapse, pH-dependent swelling and core–corona structure. Regarding drug delivery, loading efficiency for Doxorubicin and 5-Fluorouracil is maximized near the volume phase transition temperature, where hydrophobic interactions are strongest. For release studies, dialysis is recommended, but free-drug blanks are required to account for membrane-induced delay and ensure accurate early kinetic profiles. By integrating TEM, AFM, SLS, DLS, NTA and LDE, this study establishes a robust framework for the colloidal characterization of thermosensitive microgels. These refinements reduce experimental bias and may be extended to related soft nanocarriers. Full article

Spiro-dioxy-biphenyl cyclotriphosphazene derivatives, namely mono-spiro cyclotriphosphazene (SCP) and bis-spiro cyclotriphosphazene (Bis SCP), were incorporated into poly(vinyl alcohol) (PVA)–borax hydrogels to investigate the effect of phosphazene architecture on hydrogel properties and release behavior. Hydrogels containing 5 and 10 wt% phosphazene derivatives were prepared by borax crosslinking combined with freeze–thaw gelation and characterized by SEM, FTIR, thermogravimetric analysis, swelling measurements, rheological analysis, and release kinetics. SEM analysis revealed that phosphazene incorporation modified the hydrogel morphology and increased network heterogeneity. Swelling behavior strongly depended on phosphazene structure; 5 wt% SCP/PVA exhibited the highest equilibrium swelling ratio (~990%), whereas Bis SCP-containing hydrogels showed lower swelling capacities (~290–350%). Rheological measurements confirmed gel-like behavior (G′ > G″) for all formulations, and SCP-loaded hydrogels exhibited greater mechanical reinforcement than Bis SCP-loaded systems. Thermal analysis demonstrated improved thermal stability with increasing phosphazene content. Release studies performed in PBS/DMSO (1:1, pH = 7.4) revealed diffusion-controlled transport. The Higuchi (R² = 0.994–0.995) and Korsmeyer–Peppas (R² = 0.999) models provided the best fit, while diffusion exponent values (n = 0.365–0.396) indicated a mechanism of Fickian diffusion. These outcomes demonstrate that the degree of spiro substitution effectively governs the structure–property relationships of PVA–borax hydrogels for controlled-release applications. Full article

This study presents the development and evaluation of a hydrogel-based superabsorbent polymer sensor (HSPS) for measuring soil suction and establishing the soil–water characteristic curve (SWCC) of unsaturated soils. Polyacrylamide (PAM) hydrogels were synthesized via UV-induced free radical polymerization using acrylamide with varying crosslinking degrees. The polymers were characterized through FT-IR and TGA analyses, confirming successful synthesis and high thermal stability. Swelling, water retention, and kinetic behavior were systematically investigated. Results indicated that lower crosslinking density significantly enhanced swelling capacity, reaching up to 3000% in distilled water, while saline environments reduced absorption due to ionic screening effects. Swelling kinetics followed anomalous (non-Fickian) diffusion behavior and were well described by the pseudo-second-order Schott model. The synthesized polymers were integrated into a modified high-sensitivity pressure sensor operating on the osmotic principle to measure matric suction. The system was validated using natural soil. Among the tested formulations, the HSPS-3 demonstrated the most reliable suction measurements, reaching values up to approximately 1 MPa without significant temperature sensitivity. The resulting SWCC exhibited bimodal characteristics consistent with the soil’s dual pore structure. The proposed method provides a cost-effective, simple, and efficient alternative for suction measurement, expanding the practical range of SWCC determination in unsaturated soil mechanics. Full article