Search Results (10,429)

Background/Objectives: Inclusion complexes among drugs and cyclodextrin-modified polymers are a topic of recent interest in pharmaceutical research and industry as they might expand the solubility, bioavailability, and stability of the guest molecules. Polyurethanes derived from cyclodextrins show some biomedical applications. In this study, two cross-linked polyurethane networks based on hydroxypropyl-β-cyclodextrin (HPβCD) and polyethylene glycols (PEG 2000 or PEG 6000) were synthesized with NCO/OH molar ratio 4.3 and 6.3 by the typical two-step polymerization method. Methods: Inclusion complexes of clotrimazole (CLOT) with two HPβCD-modified polyurethane networks and their corresponding physical mixtures were prepared using kneading methods and physical mixing in a 1:6 weight ratio of CLOT:HPβCD. Results: Obtained prepolymers, previously end-capped with isocyanate groups forming urethane links with HPβCD, which were confirmed by FTIR analysis. TGA results indicate a slight increase in thermal stability of the prepared complexes. The characteristic endothermic peak of the CLOT at around 145.90 °C did not appear in the DSC curve of the drug-loaded inclusion complexes. The XRD patterns of physical mixtures showed specific peaks corresponding to pure clotrimazole. SEM micrographs confirmed an elliptical/spherical- and plate-shaped particles without phase segregation, indirectly confirming that CLOT is not separately present due to inclusion into HPβCD and entrapment into polyurethane networks. Novel complexes PUR2/HPβCD-CLOT-IC and PUR3/HPβCD-CLOT-IC were applied as drug carriers, and diffusion-controlled kinetics of CLOT release were best described using Higuchi model. Conclusions: The obtained in vitro results showed surprisingly slow/prolonged clotrimazole release from modified polyurethane networks due to the significant influence of NCO/OH molar ratio and the chosen polyol soft segments chain length with potential in vivo applications. Full article

High-power ultrasound has been widely used to regulate the anti-digestibility of starch-based products, including the formation of resistant starch (RS-V) in amylopectin assemblies. This can contribute to the attenuation of postprandial hyperglycemia. However, the mechanisms by which high-power ultrasound modulates RS-V remain to be elucidated. Therefore, nano-scale Euryale ferox amylopectin (EFA) ternary assemblies were constructed under high-power ultrasound. All EFA assemblies exhibited ternary self-assembly peaks and V-type crystallinity. Combined chemometric analyses revealed that, with increasing ultrasound power, the rising self-assembly sites within B2 and C chains promoted the increase in self-assembly index but decreased semicrystalline lamellae thickness and structural fractal dimension. Consequently, a compact and ordered molecular cross-linking network was formed, contributing to increases in residual crystallinity, molecular weight, short-range order, and molecular density. This resulted in the shrinkage of digestion channel structures and optimization of the molecular gel network. As a result, the reduction in hydrolysis sites with increasing ultrasound power led to increased RS-V content (22.66–60.17%), causing a decline in the estimated glycemic index. The EFA–lauric acid–lactoglobulin assemblies prepared under 600 W ultrasound were the optimal composition and exhibited enhanced anti-digestibility relative to amylopectin assemblies derived from staple crops such as white waxy maize. The present investigation not only serves as a valuable supplement for studying the precise regulation mechanisms of nano-scale amylopectin RS-V, but also provides critical theoretical guidance for the development of foods aimed at preventing hyperglycemia. Full article

Background/Objectives: The development of stimuli-responsive hydrogels for biomedical uses is an intense field of research. The use of dendritic crosslinkers can enhance the control over the structure and properties of the networks. This work presents a comparative study on the design and evaluation of Pluronic L35 thermogels, incorporating either hydrophobic carbosilane dendrimers (CBS, generations 1 to 3) or hydrophilic dendritic polyglycerols (dPG, 10 k) as crosslinkers. Methods: The thermogels were synthesized via UV-initiated thiol–ene click chemistry. Additionally, they were characterized through swelling studies, mechanical properties, degradation kinetics as well as loading and release studies of the antitumor drug doxorubicin as poorly soluble model cargo. Results: The incorporation of dendritic crosslinkers allowed higher control over the crosslinking process, while the amphiphilic polymer imparted temperature-responsive properties to the resulting networks. Remarkable differences were observed in swelling behavior, mechanical properties and degradation kinetics, depending on the nature of the dendritic crosslinker. Additionally, regarding doxorubicin loading and release in water, CBS hydrogels produced a sustained release over one week, led by network swelling, while dPG hydrogels exhibited a burst release in 4–24 h but were limited by the stronger interaction of DOX with the dPG scaffold. Conclusions: The study provided useful insight for the tailoring of dendritic thermogels for specific biomedical uses such as controlled drug delivery. Full article

The effects of red seaweed polysaccharides, e.g., carrageenan, agar gum, Porphyra haitanensis polysaccharide (PHP), and Bangia fusco-purpurea polysaccharide (BFP), on the physicochemical properties and in vitro antioxidants of silver carp surimi gels were studied. Adding appropriate concentrations of carrageenan and agar gum increased hydrophobic interactions, resulting in a denser and more uniform gel network as observed by SEM, and shortened the relaxation time of the fish balls, thus improving the gel strength and hardness of the products. When adding 0.75% carrageenan and 0.50% agar gum, the gel strength of the fish balls reached its maximum value, increasing by approximately 28.84% and 12.08%, respectively, compared to the control group (p < 0.05). However, with the over-addition of PHP and BFP, the cross-linking of surimi proteins was inhibited, resulting in a decrease in gel strength and hardness. In addition, red seaweed polysaccharide improved the free radical scavenging activity of fish balls, especially fish balls with 0.50% and 1.00% PHP and BFP exhibited better free radical scavenging activity after digestion. These findings offer insights and actionable strategies for enhancing the gel properties and function of surimi products with seaweed polysaccharides. Full article

To enhance the gelling functionality of plant proteins, this study developed hybrid gels by blending casein with soy protein isolate (SPI) at various ratios using microbial transglutaminase (MTG) as a cross-linking catalyst. The gels were systematically characterized in terms of microstructure, water distribution, rheological and textural properties, secondary structure, and intermolecular interactions. Incorporation of casein significantly improved gel strength, water-holding capacity, and network uniformity. Notably, the 1:1 casein-to-SPI ratio yielded the highest performance, featuring extensive inter-protein cross-linking, an increased proportion of ordered secondary structures, and a finely porous matrix that effectively immobilized water. Mechanistically, MTG-catalyzed covalent bonding established the primary network scaffold, while hydrophobic interactions and disulfide bonds further stabilized the gel matrix. These findings demonstrate that MTG-induced Casein–SPI hybrid gels can enhance the functional properties of plant proteins and offer a viable strategy for designing sustainable protein-based food structures with tailored performance. Full article

Primary acquired nasolacrimal duct obstruction (PANDO) is a common cause of epiphora in adults, yet the biochemical environment within the nasolacrimal duct (NLD) remains poorly understood. This study aimed to characterize the proteomic composition of NLD lavage fluid and identify subtype-specific molecular features distinguishing membranous and mucinous obstruction. Paired tear and NLD lavage fluid (NLD-LF) samples were collected from patients undergoing dacryoendoscopic recanalization, and proteomic profiling was performed using LC–MS/MS. A total of 1345 proteins were identified in NLD-LF and 767 in tear fluid, revealing a distinct NLD-specific proteome. Although the membranous and mucinous subtypes shared broadly similar protein compositions, differentially expressed proteins highlighted divergent biochemical pathways. The membranous subtype showed enrichment of keratinization-related processes involving KRT1, KRT9, and KLK13, suggesting epithelial remodeling and cornification. In contrast, the mucinous subtype exhibited upregulation of proteins involved in lipid metabolism, carboxylic acid biosynthesis, and sulfur compound metabolism, including ALOX15B, LCAT, and GSTM4, indicating metabolic conditions that promote mucin–lipid interactions, glycan sulfation, and redox-dependent mucin cross-linking. These findings provide new insights into the protein composition of NLD lavage fluid and suggest molecular differences between the membranous and mucinous obstruction subtypes. Full article

The fracturing development of low-permeability and ultra-low-permeability oil and gas reservoirs urgently requires a fracturing fluid that combines high performance and low damage. To overcome this challenge, this study synthesized a novel polyamine boron crosslinker (PBC) suitable for 0.2% guar gum. The molecular structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (¹H NMR). Meanwhile, this study introduced the response surface methodology and established a second-order regression model to determine the optimal synthesis conditions (polyetheramine 10.8 g, n-butanol 7.4 g, and ethylene glycol 20.7 g) with a model prediction error of only 0.7%. The results indicated that PBC exhibited excellent performance in 0.2% guar gum. The viscosity of crosslinked gel fracturing fluid remained stable at approximately 100 mPa·s under 60 °C and 100 s⁻¹ shear. The wall forming filtration coefficient was 2.30 × 10⁻⁴ m/s^1/2, and the initial filtration was 1.30 × 10⁻³ m³/m². The static settling rate was 2.4 cm·min⁻¹, demonstrating good suspended sand capacity. Furthermore, the synergistic interaction between borate ester bond and polyetheramine in the PBC conferred dynamic reversible crosslinking and uniform network formation. This enabled high-strength, low-damage crosslinking effects at low concentrations. This study provides an efficient crosslinker solution for 0.2% guar gum, holding both theoretical and engineering significance for advancing the low-cost development of fracturing fluid. Full article

Aesthetic medicine has progressed from the early 2000s fascination with bio-stimulation to the current dominance of hyaluronic acid (HA) fillers, prized for immediate, predictable, and reversible volumizing effects. Recently, demand for more natural results, stronger emphasis on skin quality, and increased post-pandemic self-scrutiny have renewed interest in regenerative strategies, sometimes called the “second wave of bio-stimulation.” This trend highlights the need for clearer terminology and a cautious, evidence-based reading of proposed biological mechanisms. This narrative review proposes a framework in which bio-regeneration denotes a hypothesized, controlled induction of physiological processes, fibroblast activation, collagen and elastin synthesis, extracellular matrix remodeling, and immune modulation, potentially producing sustained improvements in dermal structure and function beyond simple filling. Among emerging technologies, polyethylene glycol diglycidyl ether (PEGDE) cross-linking is reported to create a stable, flexible HA scaffold with homogeneous tissue integration, favorable rheology, thermal stability, and a reduced inflammatory profile, supporting safer multimodal use with energy-based devices. The framework is illustrated with PEGDE-crosslinked HA combined with low-concentration calcium hydroxyapatite (CaHA), exemplified by a PEGDE-HA filler containing CaHA microspheres plus glycine and L-proline. These formulations aim to deliver immediate correction via HA and delayed stimulatory effects possibly driven by gradual CaHA exposure and macrophage-associated signaling. Available clinical, imaging, and histological observations, including prospective ultrasound and biopsy assessments, suggest progressive dermal thickening and predominant type I collagen expression, without pathological inflammation or granuloma formation. Although evidence remains preliminary and largely non-comparative, findings are compatible with controlled remodeling and resolving inflammation; however, the underlying mechanism and any ‘regenerative’ versus ‘reparative’ classification require controlled comparative studies. Full article

With the increasing number of failures in high-voltage cross-linked polyethylene cables caused by buffer layer ablation, it is of great significance to investigate the electro–thermal coupling characteristics and ablation driving mechanisms under different defect conditions. Based on a multiphysics coupling model, an electro–thermal coupled simulation of the cable buffer layer and corrugated aluminum sheath was carried out, considering three typical defect types: air-gap barrier, moisture ingress, and white-powder barrier. The distributions of air-gap electric field, interfacial current density, temperature, and heat source were systematically analyzed. From the perspective of ablation mechanisms, the maximum air-gap electric field and its spatial location, as well as the maximum temperature of the buffer layer and its corresponding region, were investigated under different defect conditions. Meanwhile, the probabilities of electrical ablation and thermal ablation, together with their corresponding threshold parameters, were quantitatively evaluated. The results show that when an air-gap barrier exists between the buffer layer and the aluminum sheath, air breakdown may occur when the air-gap thickness is approximately 0.01–0.05 mm. When the buffer layer is moisture-contaminated and the defect length exceeds approximately 2 m, the buffer layer temperature may exceed 165 °C. When white-powder precipitates in the buffer layer, partial discharge may be initiated at the early stage. With the increase in powder barrier proportion, the buffer layer temperature may exceed approximately 220 °C. It should be noted that these critical characteristics are obtained under the simulation conditions of this study. The specific values depend on material parameters and operating conditions and can provide theoretical support for cable operation condition assessment. Full article

Cutaneous wound healing is a complex biological process often impaired by bacterial infections, especially by Staphylococcus aureus. To address this, alginate (ALG)/chitosan (CS) polyelectrolyte multilayer (PEM) films incorporating alginate-coated silver nanoparticles (ALG–AgNPs) were fabricated by layer-by-layer self-assembly. The films exhibited a porous, layered morphology with homogeneous distribution of ALG–AgNPs, hydrophilic surfaces (contact angle ≈ 55°), a high swelling degree (~175%), and a water vapor transmission rate of 1830 g m⁻²·day⁻¹. Thermal analyses showed similar degradation profiles up to 600 °C, with the ALG–AgNP film displaying lower moisture loss and higher dehydration temperature, consistent with enhanced ionic and coordination crosslinking (–NH₃⁺/–COO⁻ and Ag–O–C bonds). The release of Ag⁺ in PBS (pH 7.4) was ~3% after 24 h, following a Korsmeyer–Peppas mechanism (R² = 0.97, n < 0.5), and degradation, with ~40% mass loss in 6 days, indicated gradual matrix disintegration. Cytocompatibility studies revealed >80% viability for fibroblasts, keratinocytes, macrophages, and <2% hemolysis of red blood cells. Immune assays showed a tendency towards reduced TNF-α and IL-1β and regulated IL-6/IL-8 release. Antibacterial evaluations demonstrated a 5-log reduction in planktonic bacterial viability and >2-log reduction in adhesion, and an 11 ± 1 mm inhibition zone for S. aureus. These results demonstrate that ALG/CS–AgNP PEM films combine biocompatibility, antibacterial efficacy, controlled degradation, and structural stability, making them promising multifunctional scaffolds for the regeneration of infected skin wounds. Full article

Styrene–butadiene rubber (SBR) is one of the most widely used synthetic elastomers. However, the unsaturated C=C bonds in its backbone limit its long-term stability under harsh service conditions. Furthermore, conventional sulfur vulcanization forms irreversible covalent crosslinked networks, which fundamentally hinder the recyclability and reprocessability of SBR, resulting in resource waste and environmental burdens. In this work, SBR was used as the starting material. Through epoxidation and subsequent hydrogenation, followed by an epoxy ring-opening reaction, 3-aminophenylboronic acid (m-APBA) was introduced into the polymer chains, constructing a novel hydrogenated SBR with reversible dynamic cross-linking characteristics (HESBR-APBA). The resulting material exhibits superior mechanical properties compared to conventional hydrogenated SBR (HSBR) without any external additives. Notably, the HE7.4SBR-0.75APBA sample achieved a tensile strength of up to 14 MPa and retained over 95% of its original strength after multiple reprocessing cycles, demonstrating excellent mechanical stability and reprocessability. This study provides an effective molecular design strategy for balancing high mechanical performance and recyclability in hydrogenated SBR and offers new insights for developing reprocessable rubber material. Full article

Background: Hyaluronic acid (HA) hydrogels are the most widely used injectable fillers for facial rejuvenation. A new generation of HA fillers crosslinked with poly(ethylene glycol) diglycidyl ether (PEGDE) has been developed to enhance cohesiveness, tissue integration, stability, and longevity while minimizing swelling and immunogenicity. Owing to their distinct viscoelastic properties, PEGDE-crosslinked HA fillers may require product-specific selection and adapted injection techniques. Objective: The objective of this study is to provide practical, expert-based recommendations for the safe and effective use of PEGDE-crosslinked HA hydrogels in facial aesthetic treatments. Methods: A multidisciplinary panel of nine Italian experts in aesthetic medicine, each with more than 15 years of experience using HA fillers, developed consensus recommendations based on clinical practice and available evidence. A pre-meeting questionnaire informed structured discussions during a face-to-face meeting held in Paris in January 2024. The nominal group technique was applied, with consensus defined as agreement by at least 80% of panel members. Results: Consensus was reached on product selection, injection planes, delivery devices, techniques, and typical treatment volumes for PEGDE-HA hydrogels across multiple facial regions, including the forehead, temples, midface, nasolabial folds, chin, jawline, and lips. Recommended injection techniques included microbolus, macrobolus, and retrograde linear threading, with placement ranging from superficial subcutaneous to supraperiosteal planes depending on the anatomical area and clinical indication. Typical injection volumes generally ranged from 0.1 to 0.5 mL per side. Optional ultrasound mapping was considered beneficial in selected high-risk or superficial procedures to improve anatomical safety. Conclusions: These expert consensus recommendations provide practical guidance for clinicians using PEGDE-crosslinked HA hydrogels in facial rejuvenation. Tailoring product characteristics to injection depth, technique, and regional anatomy may help optimize clinical outcomes and procedural safety. Future research priorities include prospective comparative studies with other crosslinking technologies, standardized reporting of adverse events, long-term outcome registries, and further evaluation of ultrasound-guided injection strategies. Full article

Coke, as an essential metallurgical raw material, is widely used in iron and steel production. To investigate the pyrolysis behavior and cross-linking reactions during the pyrolysis of coking coal, pyrolysis experiments were conducted in a quartz-tube fixed-bed reactor placed in an electric furnace. The yields and compositions of the pyrolysis products were systematically analyzed. Gaseous and tar components generated at different pyrolysis stages were characterized using gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The semi-coke was examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results indicated that the yields of tar from coking coal pyrolysis have a notable impact on the cross-linking reactions occurring during the coal pyrolysis process. The structural differences between Malan coal (ML) and Tunlan coal (TL) coals underlie their distinct behaviors in cross-linking intensity, tar evolution profiles, and coke-forming properties. For high-volatile, highly fluid ML coal, the release of the aliphatic compounds in tar volatiles remains relatively low at the temperature of maximum fluidity, which is beneficial to the cross-linking reactions. In contrast, for TL coal with lower volatility and fluidity, substantial H₂ emission during the early pyrolysis stage promotes cross-linking reactions. This study provides new insights into the temperature-dependent evolution of cross-linking reactions during coking coal pyrolysis. Full article

Hydrogels are endowed with exceptional hydrophilicity and biocompatibility by their network structure, while also exhibiting soft physical properties similar to living tissues, which renders them ideal biomaterials. Responsive hydrogels—particularly those constructed from multicomponent systems including proteins, polysaccharides, peptides, and polyphenols—have emerged as a frontier research focus owing to their tunable responsiveness and controllable functional properties. In this review, hydrogel response mechanisms were categorized according to pH, ionic strength, temperature, light, enzymes, and multi-stimuli interactions. Key preparation strategies, encompassing chemical, physical, and enzymatic crosslinking, were systematically introduced. The preparation of hydrogels from various food-grade matrices, such as polysaccharide-based, protein-based, peptide-based, and polyphenol-based systems, was also summarized, with emphasis placed on how their tailored structures govern functional performance. Furthermore, innovative applications of responsive hydrogels were highlighted, including targeted delivery of nutrients and bioactive substances (e.g., probiotics, anthocyanins, vitamins) in functional foods, smart packaging and sensing for real-time freshness monitoring of meat and fruits, food quality detection through colorimetric and photothermal sensors, and 4D food printing for personalized nutrition and dysphagia-friendly foods. Full article

Biocompatible nanocomposite hydrogels are emerging as versatile platforms in nanomedicine, particularly when natural proteins are used as both structural and chemical components. In this work, we report a green, simple, and rapid in situ synthesis of ultrasmall silver nanoparticles (uAgNPs) within a bovine serum albumin (BSA) hydrogel, in which albumin simultaneously acts as the reducing agent and three-dimensional scaffold. The confined reaction environment generated uniformly dispersed Ag nanostructures with diameters in the 4–40 nm range, as confirmed by DLS and TEM. High-resolution TEM revealed clear Face-Centered Cubic (FCC, 111) lattice fringes, demonstrating the crystalline nature of the embedded uAgNPs. Quantitative image analysis showed narrow size distributions and high circularities, consistent with cluster stabilization through protein–metal interactions. Rheological measurements further indicated that the incorporation of uAgNPs enhanced hydrogel stiffness and delayed yielding, reflecting a reinforcement effect mediated by the nanoparticles acting as additional cross-linking points. Moreover, when very small embedded uAgNPs are formed, the presence of emissive silver nanoclusters was found using fluorescence emission spectroscopy. Overall, our results show that BSA hydrogels provide an effective matrix for directing green uAgNP nucleation, ensuring high stability, controlled growth in less than 2 min, and improved mechanical properties. The resulting protein–nanoparticle composite constitutes a promising soft material for imaging, sensing, and other biomedical applications requiring stable, biocompatible nanoscale architectures. Full article