Search Results (439)

N-acetylcysteine (NAC) is a thiol-containing molecule with antioxidant, anti-inflammatory, antimicrobial, and cytoprotective properties that has increasingly been incorporated into hydrogel-based biomaterials. This systematic review evaluates the strategies used to integrate NAC into hydrogels and examines their effects on material properties, controlled release, biocompatibility, and therapeutic activity. The review was conducted according to the PRISMA guidelines using Scopus, PubMed, Web of Science, and SciFinder to identify English-language articles published between 2000 and 2025. Seventy-three studies met the eligibility criteria of this review. NAC has been employed as a physically loaded therapeutic agent, covalently conjugated polymer modifier, contributor to hydrogel crosslinking, metal-coordination ligand, and compound incorporated into nano- and microparticulate carriers dispersed in hydrogel. These approaches enable the modulation of gelation, swelling, adhesion, degradation, and drug-release kinetics. NAC-containing hydrogels have demonstrated robust antioxidant, antimicrobial, antibiofilm, anti-inflammatory, angiogenic, and tissue-regenerative properties in various in vitro and in vivo models, underscoring their potential for advanced biomaterial applications. Release profiles varied from rapid stimulus-responsive delivery to sustained release over several days, depending on the network architecture and the NAC–matrix interactions. However, comparisons among studies were limited by the heterogeneous formulations, release conditions, biological models, and outcome measures. Standardized physicochemical characterization, NAC stability assessment, dose–response evaluation, and rigorous preclinical validation are required to support the translation of NAC-based hydrogels into biomedical applications. We hope that this review will help scientists and innovation centers understand the potential of the NAC-containing hydrogel biomaterials discussed in this study, as well as the opportunities and demands for additional research in this field. Full article

Background/Objectives: Renal ischemia–reperfusion injury (IRI) and infection-associated renal damage are characterized by persistent inflammation, oxidative stress, microvascular dysfunction, and impaired tissue regeneration, creating a hostile microenvironment that limits effective repair. We developed an injectable, photocrosslinkable methacrylated chitosan (CSMA) hydrogel for the localized co-delivery of cerium oxide nanoparticles (CeO₂NPs) and vascular endothelial growth factor (VEGF), aiming to integrate redox modulation, antibacterial activity, and regenerative support. Methods: Gelation, microstructure, rheology, degradation, and CeO2NP/VEGF were characterized. Tubular epithelial and fibroblast migration and endothelial network formation, angiogenic gene expression, and antibacterial activity against Staphylococcus aureus and Escherichia coli were evaluated in vitro. Theraputic performance was assessed by renal surface application in a rat renal IRI model and catheter-mediated interavsical administration in an ascending urinary tract infection model. Systematic biocompatibility was evaluated separately in a 14-day subcutaneous implantation study. Renal response were further investigated using transcriptomic and targeted molecular analyses. Results: The CSMA/VEGF/CeO₂NPs hydrogel exhibited rapid in situ gelation, interconnected porous architecture, stable viscoelasticity, gradual degradation, and sustained release of both CeO₂NPs and VEGF. The formulation enhanced tubular epithelial and fibroblast migration, promoted endothelial network formation and angiogenic gene expression and effectively inhibited both S. aureus and E. coli. In a surgically controlled rat renal IRI model, direct renal-surface application of the hydrogel reduced tubular injury, inflammatory infiltration, and fibrotic remodeling. In a separate ascending urinary tract infection model, catheter-based intravesical administration reduced the ascending renal bacterial burden and infection-associated inflammatory injury. No detectable adverse systemic effects observed under the tested conditions over the 14-day observation period in the subcutaneous implantation. Transcriptomic analyses further revealed that CSMA/VEGF/CeO₂NPs treatment was associated with marked remodeling of the renal injury microenvironment, characterized by suppression of antigen presentation and immune activation pathways, alongside restoration of metabolic programs associated with amino acid, lipid, and purine metabolism. These molecular changes were accompanied by downregulation of CIITA/CD74/MHC-II signaling, recovery of metabolic regulators AGXT and ACOX1, modulation of Hippo/YAP- and ECM-associated pathways, and preservation of renal structural markers including nephrin and WT1. Conclusions: The localized CSMA-mediated co-delivery of CSMA/VEGF/CeO₂NPs hydrogel promotes renal repair through resolution of maladaptive immune activation, metabolic reprogramming, angiogenic enhancement, and preservation of renal structural integrity, providing a promising biomaterial strategy for the treatment of ischemic and infection-associated renal injuries. Full article

The development of plant protein-based delivery systems is often limited by poor stability and low retention efficiency under gastrointestinal conditions. This study investigated how pH (4 and 7) during external gelation influences the physicochemical properties, entrapment efficiency (EE), and in vitro gastrointestinal behaviour of alginate beads loaded with hemp protein concentrate (HPC), pea protein concentrate (PPC), or soy protein isolate (SPI). Zeta potential and Fourier transform infrared (FTIR) analyses suggested that at pH 4, the charge profiles of plant proteins favoured electrostatic association with anionic alginate, which was associated with higher EE values, with HPC achieving the maximum of 89.5% at pH 4. Conversely, at pH 7, electrostatic repulsion between biopolymers was associated with reduced EE. During in vitro digestion, beads formulated at pH 4 exhibited greater protein release than those prepared at pH 7, consistent with the expansion of the polymeric network under intestinal conditions. Size exclusion chromatography showed that released proteins underwent extensive proteolysis, generating low-molecular-weight fractions smaller than 300 Da. These results indicate that gelation pH is a relevant processing parameter for modulating protein retention and the extent of protein release of simulated digestion in alginate-based systems, with potential applications in protein-enriched food formulations. Full article

Reducing sodium in meat products is nutritionally desirable, but salt reduction often weakens myofibrillar protein gelation and reduces texture quality and water retention. This study investigated the effects of L-lysine (Lys) and konjac glucomannan (KGM) on the physicochemical properties, gel characteristics, and structural changes of beef myofibrillar protein (MP) gels under low-salt conditions. The results indicated that reducing NaCl from 0.6 to 0.2 M decreased water-holding capacity (WHC), increased cooking loss, and produced a loose gel network. Compared with the 0.2 M NaCl group, the combined Lys-KGM treatment increased WHC from 28.53% to 56.70% and reduced cooking loss to 22.19% (p < 0.05). Texture analysis showed that Lys-KGM increased hardness and springiness by 69.40% and 80.43%, respectively (p < 0.05). LF-NMR indicated a higher proportion of immobilized water and reduced water mobility in the combined treatment. Lys increased reactive sulfhydryl content and surface hydrophobicity, whereas KGM reduced surface hydrophobicity and enhanced water immobilization. Lys-KGM slightly but significantly decreased α-helix and increased β-sheet contents (p < 0.05), accompanied by changes in the relative contributions of intermolecular forces and a more continuous gel network. Molecular docking and molecular dynamics simulations provided supporting evidence for different interaction patterns between myosin and Lys/KGM. These results suggested that Lys and KGM might help maintain the quality of low-salt meat protein gels and provide a formulation basis for reduced-sodium meat products. Full article

Goose bone paste is an underutilised poultry-processing by-product and a potential source of taste-active peptides. A nominal 1–3 kDa peptide fraction (F2), operationally designated an umami peptide fraction by analogy with comparable bone-hydrolysate fractions reported in the literature, was isolated from a neutral-protease hydrolysate by sequential ultrafiltration and encapsulated in sodium alginate (SA) microcapsules using extrusion–dripping ionic gelation. Single-factor screening identified the following formulation conditions: 2.0% (w/v) SA, 2.5% (w/v) CaCl₂, 0.3% (w/v) SE-15, a core-to-wall mass ratio of 0.3, and a preparation temperature of 50 °C. A verification batch prepared under these conditions gave an encapsulation efficiency of 75.44%, with the ±1.07% denoting the SD of three technical determinations from that batch. The dried microcapsules had a moisture content of 2.98 ± 0.21% and passable flowability. The mean particle diameter was 856 ± 52 μm, with a within-batch coefficient of variation of 5.56 ± 0.28%; a complete particle-size distribution was not recorded. In pepsin-free simplified simulated gastric fluid, the apparent release from the microcapsules rose from about 6% at 1 h to about 13% at 5 h, whereas the apparent detection ratio of free F2 rose from about 56% to about 99%. The calculated concentrations fell at or below the validated limit of quantification, the microcapsule-group absorbances lay near the photometric floor of the instrument, and only three sampling times were used. These percentages and the kinetic fits are therefore qualitative to semi-quantitative. The data support only the relative statement that alginate encapsulation lowered the apparent release of F2 under the tested acidic conditions. They do not establish an exact release rate, an error estimate for the microcapsule group, or a specific release mechanism. Full article

Sea cucumber mouthpart peptides (SCPs) are marine bioactive peptides with considerable application potential. However, their oral delivery remains challenging because of their poor stability and low intestinal bioavailability. To develop a delivery system for SCPs with gastric protection and pH-responsive intestinal sustained-release properties, double-layer gel beads (SCP-BMs) were fabricated through ionic gelation, with SCPs as the core material and sodium alginate (SA) and chitosan (CS) as the wall materials. The preparation conditions of the gel beads were optimized using single-factor experiments and response surface methodology (RSM). The optimized gel beads were then characterized for their morphology, thermal stability, in vitro gastrointestinal release behavior, and antioxidant activity. The results showed that the optimal preparation conditions were 1.67% (w/v) sodium alginate, 0.96% (w/v) chitosan, and 2.16% (w/v) CaCl₂. Under the optimized conditions, the encapsulation efficiency (EE) reached 94.33%, significantly higher than that of the single-layer gel beads (SCP-SMs, 58.61%). Structural characterization showed that SCP-BMs exhibited a more compact structure than SCP-SMs, along with improved thermal stability. In vitro release and antioxidant assays demonstrated that SCP-BMs exhibited better gastric protection, pH-responsive intestinal release, and higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activity compared with SCP-SMs. This study demonstrated that the SA/CS double-layer wall material system effectively improved the encapsulation efficiency, structural stability, and intestinal release behavior of SCP gel beads. These findings provide a feasible strategy for the development of SCP delivery systems and offer a theoretical basis for the high-value utilization of sea cucumber byproducts. Full article

Efficient gas drainage in soft coal seams is commonly impeded by two coupled issues: coal-fines-induced clogging of screens and boreholes, and instability of the borehole wall. To overcome these limitations, an in situ grouted porous polyurethane system was developed for borehole completion. The polyurethane slurry, consisting of isocyanate, polyether polyol, catalyst, foam stabilizer, cell-opening agent, cross-linker, and water as a blowing agent, was formulated to coordinate foaming and gelation kinetics. By adjusting the type and dosage of catalyst, the gel time could be precisely controlled within 10–1500 s to suit different construction requirements. After curing, the material exhibited an interconnected open-cell structure with a porosity of approximately 83%, permeability greater than 4 D, and a uniaxial compressive strength of about 1.72 MPa. Mercury intrusion porosimetry revealed a highly connected, multiscale pore network, with an accessible porosity of 78.9%, a median pore size of 125 μm, and a dominant pore-size range of 1–301 μm, indicating favorable conditions for gas flow. Flow-through experiments under simulated methane drainage showed that coal-fine production is strongly dependent on flow rate: fines generation was negligible at flow rates ≤20 L/min and became noticeable at around 30 L/min. Scanning electron microscopy confirmed that coal fines were confined to the upper ~5 mm of the consolidation layer, where bridging and straining within small near-surface pores limited deeper penetration. Although near-surface fines deposition reduced permeability from the intrinsic polyurethane value (~4.0 D) to ~2.0 D, the permeability stabilized above ~1.5 D under dynamic conditions. Overall, these laboratory-scale results demonstrate that the porous polyurethane can effectively intercept coal fines within a shallow surface zone, provide sufficient mechanical support to stabilize the borehole, and maintain high permeability under the tested conditions, suggesting its potential as a candidate material for enhancing methane drainage performance in soft coal seams. Further field validation and comparative studies against conventional completion systems are needed to assess its true engineering viability. Full article

Hibiscus sabdariffa L. is a valuable source of phenolic compounds, including anthocyanins with recognized antioxidant and health-related properties; however, their instability under processing and storage conditions limits their direct application in food and nutraceutical systems. In this context, encapsulation offers a promising strategy for enhancing the stability and delivery of hibiscus bioactives. The present study comparatively evaluates three encapsulation techniques, spray drying, co-crystallization, and ionic gelation, for the stabilization of aqueous hibiscus extract. Each process was optimized through systematic adjustment of key operating parameters. The encapsulated products were characterized for physicochemical properties (moisture content, bulk density, wetting time, hygroscopicity, color, particle morphology), encapsulation efficiency, antioxidant capacity, anthocyanin content release behavior, and structural interactions through Fourier-transform infrared (FTIR) analysis. The encapsulation method strongly affected phenolic retention, antioxidant activity, color characteristics, and release behavior of the final products. Under the optimized conditions, encapsulation efficiency was approximately 95% for spray drying, while co-crystallization showed an apparent encapsulation efficiency of 99.96%, whereas ionic gelation showed measured values of 7.0–34.0% and a model-predicted, validated optimum of 50.83%. Spray drying better preserved antioxidant activity, anthocyanin content, and color characteristics, while co-crystallization produced low-moisture, low-hygroscopicity powders with rapid aqueous release. FTIR analysis of the spray-dried and co-crystallized samples indicated physical entrapment rather than chemical modification, confirming the successful formation of encapsulated systems. Τhe findings highlight method-dependent differences in the technological and functional performance of the encapsulation systems, providing insight into the stabilization and controlled release of hibiscus-derived bioactive ingredients, with spray drying and co-crystallization emerging as the most promising approaches. Full article

Background/Objectives: Natural clinoptilolite–amoxicillin hybrids (CNZ@AMOX) were incorporated into alginate microcapsules via ionic gelation to develop a hybrid mineral–polymer delivery system for the controlled release of amoxicillin. Methods: A face-centered central composite design combined with response surface methodology (FCCD-RSM) was utilized to assess the effects of the zeolite/sodium alginate ratio, alginate concentration, calcium chloride concentration and curing time on the encapsulation efficiency (EE), sphericity factor (SF), and roundness (Rn). Results: The EE ranged from 5.9% to 91.3%, depending on the formulation composition. Numerical optimization identified the optimal conditions as 70.962% EE, 0.05 SF and 1.00 Rn, with a desirability score of 0.873. The incorporation of natural clinoptilolite improved microcapsule structural integrity and reduced the initial burst release by modulating diffusion pathways within the hybrid matrix. The optimized CNZ@AMOX exhibited pH-dependent release behavior, with minimal drug release in simulated gastric fluid (SGF) and diffusion-controlled release in simulated intestinal fluid (SIF), which was best described by the Korsmeyer–Peppas model. Conclusions: These findings demonstrate that zeolite–alginate hybrid microcapsules represent promising inorganic–organic composite carriers for the pH-responsive and controlled delivery of AMOX. Full article

A comprehensive evaluation of allogeneic human bone-derived gelatin (hBG) was conducted as a promising material for regenerative medicine and 3D bioprinting. Comparative analysis with a commercial animal-derived gelatin product (hereinafter CDH) revealed a similar FTIR spectral profile, confirming the retention of key functional groups. Rheological analysis under steady shear showed that hBG is a pseudoplastic fluid with a concentration-dependent viscosity. However, a complete characterization of bioinks requires oscillatory measurements (G′, G″, and gelation point), which are planned in future studies. In vitro experiments on spheroid models (chondroblasts) demonstrated biocompatibility, an absence of cytotoxicity, and support for cell viability in 5% and 10% (hBG-5/10) matrices. Owing to its origin, the material allows for the modeling of “human-in-human” conditions, which makes it a promising precursor for the development of bioinks and matrices in regenerative medicine and tissue engineering. However, definitive positioning of the material as a bioink requires additional oscillatory rheological studies (determination of G′, G″, thixotropy, and gelation point), which were not performed in the present work. Full article

Understanding mass transport of structurally different drugs within ionically crosslinked hydrogel networks remains an important challenge in polymer-based delivery systems. In this study, hydrophilic amoxicillin (AMOX) and amphiphilic doxycycline (DOX) were encapsulated into calcium–alginate beads, respectively. A three-factor and three-level Box–Behnken design was utilized to examine the influences of alginate concentration (2–5%, w/v), CaCl₂ concentration (1–3%, w/v), and gelation time (15–45 min) on encapsulation efficiency (EE). EE exhibited considerable variability for both AMOX (10–86%) and DOX (10–63%). Optimal EE values were achieved at almost 3.5% alginate and 3% CaCl₂. The optimized gelation times differed between AMOX (45 min) and DOX (15 min), which is likely associated with differences in their physicochemical properties, although additional intermediate gelation times could further refine the optimal conditions. ANOVA identified CaCl₂ concentration and the quadratic effect of alginate as the most influential parameters. Furthermore, both models demonstrated robust predictive capability (R² > 0.98). In vitro release experiments demonstrated minimal drug diffusion in simulated gastric fluid (SGF) and significantly accelerated release in simulated intestinal fluid (SIF). These findings indicate a pH-responsive release behavior under simulated gastrointestinal conditions. The release profile was best represented by Higuchi and Korsmeyer–Peppas kinetic models. SEM and optical microscopy revealed uniform spherical beads with drug-dependent microstructural differences: hydrophilic AMOX produced smoother, wrinkled surfaces, whereas amphiphilic DOX induced localized cracking and heterogeneous microdomains. Furthermore, DLS and zeta potential measurements of the released fractions indicated nanoscale particle populations (≈190–225 nm) with moderate negative surface charge (≈−21 mV), suggesting stable colloidal dispersion during intestinal-phase release. Full article

Nanoparticles of the aminopolysaccharide chitosan (ChNPs) are effective delivery platforms for biologically active substances for agrobiotechnological applications and hold great promise for solving precision problems in sustainable and efficient agriculture. This review presents an analysis of research publications during the past 20 years examining methods for producing ChNPs through ionotropic gelation using sodium tripolyphosphate for cross-linking macrochains, which are of practical interest for agriculture. Key aspects of the nanostructure formation process are analyzed, including the influence of the physicochemical characteristics of the aminopolysaccharide, the concentration and ratio of reagents, and ionic cross-linking conditions on the average size, size distribution (polydispersity), and zeta potential of nanoparticles. Particular attention is paid to several approaches proposed in the literature for determining optimal gelation conditions to obtain ChNPs with pre-specified size characteristics. Potential applications of nanostructured preparations based on these nanoparticles for agrobiochemical purposes are considered, including the encapsulation of antifungal, antiviral and antimicrobial agents, pesticides, NPK fertilizers, metal ions, plant extracts, essential oils, etc., to develop biodegradable stimulants for seed germination and plant growth, increased crop yields, and improved agricultural product quality. It is concluded that blocking the protonated amino groups of chitosan with tripolyphosphate anions is undesirable due to the reduced biological activity of the macromolecules and the nanostructured preparations obtained therefrom. An alternative approach for producing ChNPs with high biological activity with neither use of cross-linking agents nor encapsulation of agrochemicals is described. Full article

This study investigates the synthesis–structure relationships governing sol–gel-derived nanostructured MgFe₂O₄ ferrite powders for high-temperature thermochemical energy conversion applications. The effects of key processing parameters, including propylene oxide (PO) concentration, gel aging time, calcination temperature, and calcination duration, were systematically examined to tune the phase composition, specific surface area (SSA), pore volume, crystallite size, and nanoparticle morphology of MgFe₂O₄. Increasing the PO concentration from 5 to 20 mL shortened the gelation time from 585 to 323 s and increased the SSA from 5.30 to 17.88 m²/g, while the pore volume increased from 0.0074 to 0.0210 cm³/g. In contrast, gel aging time between 24 and 120 h produced negligible changes in SSA, pore volume, and crystallite size, indicating that extended aging is not required for microstructural control. Calcination temperature strongly influenced the nanostructure: increasing the temperature from 600 to 1000 °C decreased SSA and pore volume while increasing crystallite size from 21.33 to 48.76 nm. Longer calcination times produced a similar but less pronounced effect, decreasing SSA from 18.83 to 14.89 m²/g and increasing crystallite size from 17.55 to 30.12 nm. Overall, phase-pure MgFe₂O₄ with favorable textural properties was obtained using 20 mL of PO, 24 h of aging, and calcination in the 700–800 °C range. Under the identified synthesis conditions, namely 20 mL of PO, 24 h of aging, and calcination in the range of 700–800 °C for 2 h, phase-pure MgFe₂O₄ nanoparticles with particle sizes of approximately 10–50 nm were obtained. These results establish a processing–microstructure framework for engineering MgFe₂O₄ nanomaterials with tunable textural properties for solar thermochemical redox cycles and related high-temperature energy applications. Full article

Amino acid-based surfactants are promising ingredients for cosmetic formulations, combining mildness with intrinsic self-assembly properties. A recent challenge in the cosmetic field is the replacement of synthetic polymers, used as rheological modifiers, with sustainable and biodegradable alternatives. In this work, sodium cocoyl glycinate (SCG) and sodium cocoyl alaninate (SCA) were investigated as both surfactants and supramolecular gelators for the development of a “supramolecular shampoo”. pK_a analysis and rheological studies revealed that SCG forms robust gel networks at pH 5, whereas SCA shows limited stability. The progressive incorporation of typical cosmetic ingredients, including cocamidopropyl betaine (CAPB), preservatives, conditioning agents, and fragrance, led to a controlled decrease in mechanical strength while preserving pseudoplastic behavior. The final formulation remained stable under accelerated aging and freeze–thaw conditions for months. These results demonstrate that supramolecular structuring offers a viable and sustainable alternative to conventional polymer-based systems in shampoo formulations. Full article

Calcium-induced polysaccharide hydrogels have attracted growing interest in food science because of their mild gelation conditions, tunable structures, and compatibility with food-grade formulation. This review focuses on edible Ca²⁺-mediated polysaccharide hydrogels and related composite networks, focusing on alginate, low-methoxyl pectin, gellan gum, and carrageenan. Rather than treating all calcium-containing polysaccharide materials as well-defined complexes, we distinguish direct coordination, ionic bridging, charge screening, helix stabilization, and composite-assisted network regulation. Current evidence indicates that Ca²⁺-mediated assembly is governed by polysaccharide fine structure, calcium-release behavior, pH, ionic strength, and processing conditions, thereby determining crosslinking density, digestibility gel strength, water distribution, rheological properties, release behavior, and texture-related functionality. For texture-modified foods for older adults, these hydrogels may provide a useful material basis for designing swallowing-friendly matrices, sustained nutrient-delivery systems, and soft composite foods. However, available evidence is still largely derived from model gels, in vitro characterization, and static digestion models, while validation in real food matrices, dynamic gastrointestinal conditions, oral processing, sensory acceptance, and older-adult populations remains limited. Future studies should establish structure–function–population evidence chains linking molecular assembly to reliable geriatric food performance. Full article