Search Results (91)

Neurodegenerative diseases arise when normally functional aggregation-prone proteins transition into stable cross-β amyloid fibrils. Although these fibrils share a conserved architecture, the pathways that lead to fibrillation vary across proteins and cellular environments. Liquid–liquid phase separation is now recognized as a central organizer of intracellular biochemistry that modulates protein aggregation. Physiological condensation can buffer aggregation by maintaining macromolecular solubility and providing partner interactions that compete against pathological protein–protein interactions. However, condensates can transform and age into gel-like states that can favor the emergence of β-rich oligomers and solid-state fibrils. Across six disease-linked proteins that include Tau, ⍺-synuclein, amyloid-β, TDP-43, FUS, and hnRNPA1, we compare how sequence-encoded interaction motifs, cellular cofactors, and interfacial microenvironments shape the balance between physiological condensates and pathological amyloids. Here, we highlight the unifying drivers of aggregation and intervention points that preserve native function while limiting toxic amyloid formation. Full article

Frozen surimi, a commonly used raw material in processed aquatic products, is vulnerable to repeated freeze–thaw fluctuations that accelerate protein denaturation and quality loss. In this study, root-derived Flammulina velutipes polysaccharides (FVPs) were extracted from the root-like portion of enoki mushroom, and surimi supplemented with 2% FVP and a blank control (CK) were stored at −18 °C and subjected to a total of five freeze–thaw cycles. The effects of FVP on myofibrillar protein (MP) characteristics and the storage quality of catfish surimi during the freeze–thaw cycles were analyzed. Compared with CK, FVP markedly alleviated the deterioration of water-holding capacity, gel strength, and MP solubility throughout freeze–thaw cycling. It also effectively inhibited the increase in thiobarbituric acid reactive substance (TBARS) values and MP aggregation and delayed the rate of decrease in the storage modulus (G′) and loss modulus (G″) of surimi. Additionally, low-field nuclear magnetic resonance (LF-NMR) further showed that FVP limited the conversion of immobilized water to free water, indicating enhanced water retention under repeated freeze–thaw stress. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses revealed that FVP stabilized the secondary structure of MPs, making the microstructure of surimi more uniform and compact. The results of this study indicate that FVP exhibited significant cryoprotective effects during freeze–thaw cycles of surimi relative to the untreated control group, providing a theoretical basis for its potential application in aquatic product storage. Full article

Neurodegenerative diseases feature diverse pathological protein aggregates, including Lewy bodies in Alzheimer’s disease (AD) and skein-like filaments in amyotrophic lateral sclerosis (ALS). The physical mechanisms underlying this morphological diversity remain unclear. Here, we demonstrate that aggregation of the prion-like domain of hnRNPA1 (A1PrD), implicated in AD and ALS, is driven by solution composition and phase transition dynamics. Utilizing 3D timelapse and fluorescence lifetime imaging microscopy, we show that solution conditions modulate phase separation, gelation, and fibrillation, resulting in distinct structures such as fibril, gel, and starburst morphologies. Homotypic and heterotypic interactions between A1PrD and RNA were observed to shift the balance between pathological and physiological condensates. Importantly, amyloid-rich starbursts displayed prion-like infection capabilities toward amyloid-poor condensates. Our findings highlight how the interplay between solution composition and kinetic balances of liquid-liquid phase separation, gelation, and fibrillation shapes the diverse pathological aggregate morphologies characteristic of neurodegenerative diseases. Full article

We reported a simplified one-step emulsification strategy to prepare bi-continuous emulsions with a gel-like property using the pH-responsive self-assembled aggregates of an amphiphilic random copolymer poly (styrene-co-methacrylic acid) (P(St-co-MAA)) as the interfacial stabilizers. Using caprylic/capric triglyceride (GTCC) as the oil phase, 1.0% P(St-co-MAA) aqueous solution with a pH between 7.0 and 8.0 as the water phase, and an oil/water phase ratio of 6:4, bi-continuous emulsions could be formed directly through one-step emulsification. Systematic characterization with a fluorescence microscope, scanning electron microscope, and confocal laser scanning microscope confirmed the formation of the bi-continuous emulsions. The three-phase contact angle measurements confirmed that the surface wettability of the self-assembled aggregates changed with pH, and the three-phase contact angles of the bi-continuous emulsions formed at a pH between 7.0 and 8.0 were close to 90°. Furthermore, rheological analysis of the bi-continuous emulsion showed the storage modulus (G′) dominating over the loss modulus (G″), which verified that the bi-continuous emulsion was attributed to the existence of a three-dimensional elastic gel network. The pH-dependent wettability of the self-assembled aggregates as the stabilizers enabled pH to control the emulsion type from O/W to bi-continuous to W/O. The work provides a simple, rapid, and robust approach to preparing bi-continuous emulsions without intricate particle modifications and cumbersome procedures. Full article

This review work highlights the eco-friendly synthesis and application of biomass-derived silica gel (SG)-supported metallic nanoparticles (MNPs), primarily focusing on their potential for sustainable drinking water disinfection and utilizing abundant biomass waste, such as agricultural residues, to extract silica through processes like pyrolysis, chemical treatment, or hydrothermal methods, creating a versatile support with high surface area, porosity, and biocompatibility. MNPs, notably silver, copper, zinc, etc., are immobilized onto these silica frameworks via green synthesis techniques, including plant extract-mediated methods, chemical reduction, and sol–gel processes, resulting in nanocomposites with controlled size, distribution, and enhanced stability. These MNPs are known for their potent antimicrobial activity, capable of inactivating a broad spectrum of pathogens like Staphylococcus aureus and Escherichia coli. Silica gel supports mitigating issues such as nanoparticle aggregation and leaching, thus improving reusability and environmental safety. The synthesis parameters of nanoparticle size, concentration, surface chemistry, and contact time directly influence disinfection efficacy, while biomass-based supports offer advantages including cost-effectiveness, environmentally benign production, and minimal pollution. Incorporating biomass-derived silica gel-supported AgNPs into water treatment systems presents a promising, sustainable alternative to conventional chemical methods like chlorination and ultraviolet (UV) irradiation, which can generate hazardous byproducts. These nanocomposites demonstrate significant potential in resource-limited settings due to their high surface area, porosity, and reusability, although concerns such as nanoparticle leaching, toxicity, scalability, and environmental impact warrant further investigation. Overall, biomass-supported MNPs represent an innovative frontier in water purification technology, aligning with principles of green chemistry and sustainability. Emphasizing the importance of optimizing synthesis protocols and assessing long-term safety, this review underscores their capacity to advance eco-friendly water disinfection strategies that can improve public health and promote sustainable water management practices worldwide. Full article

Developing adsorbents that combine high capacity with structural robustness remains a critical challenge for dye wastewater treatment. In this study, we propose a “pollutant-induced gelation” strategy to address this limitation, using Fe(III)-activated palygorskite nanorod aggregates as a model system for the highly efficient sequestration of Congo red (CR). Unlike conventional modification methods that rely solely on surface functionalization, this approach leverages the adsorbed dye itself as a synergistic assembly promoter. The addition of CR significantly consolidates the Fe(III)-mediated aggregation of palygorskite nanorods, leading to the formation of an integrated three-dimensional porous network with distinct gel-like rheological behavior. This dye-induced gel network not only provides abundant confined spaces for pollutant entrapment but also enhances the structural integrity of the adsorbent, facilitating separation and potential reuse. Compared to pristine palygorskite, the Fe(III)-activated material exhibited a 95.4–277% increase in adsorption capacity across a pH range of 4–10. The adsorption process followed pseudo-second-order kinetics and the Temkin isotherm model, and was thermodynamically spontaneous and exothermic. Mechanistic studies revealed a synergistic interplay: Fe(III) served as primary cross-linking nodes to construct the network framework, while CR molecules acted as inducers to reinforce the gel architecture, enabling strong physical immobilization of dye aggregates. This work provides a new paradigm for designing intelligent, gel-based adsorbents from natural nanoclays, transforming a pollutant into a structural promoter. Full article

In the fabrication of ultrathin multilayer ceramic capacitors (MLCCs), the long-term stability of ceramic slurries is a critical yet often overlooked factor that can significantly influence coating uniformity, interfacial adhesion, and process reproducibility. Despite its industrial importance, the time-dependent evolution of slurry dispersion structures during storage and its direct impact on green sheet properties remain insufficiently understood. This study examined the time-dependent physicochemical evolution of barium titanate (BaTiO₃)-based green sheet slurries, which behave as colloidal gel-like dispersion systems, and their influence on the structural, optical, and interfacial properties of the resulting sheets. Dynamic light scattering revealed progressive yet uniform particle aggregation, while viscosity measurements indicated a gradual ~10% decrease over 960 h, reflecting reduced dispersion stability and progressive weakening of the slurry gel network during extended storage. The slurry, consisting of BaTiO₃ particles, polymeric binders, and plasticizers, forms a three-dimensional transient gel network, in which particle–particle and particle–binder interactions govern rheological behavior. The observed viscosity decrease and turbidity reduction indicate gel network relaxation and partial gel–sol–like transition behavior driven by aggregation. Cross-sectional scanning electron microscopy demonstrated that these changes produced a measurable reduction in final green sheet thickness, despite identical processing conditions. Furthermore, peel tests revealed that interfacial adhesion strength increased with storage time, attributable to localized solid enrichment within the slurry gel matrix and enhanced bonding at the release film interface. The reduced coating thickness also contributed to lower optical haze, reflecting a shortened light-transmission path. Collectively, these findings demonstrate that even moderate aggregation in a ceramic network-forming dispersion system substantially alters coating behavior, adhesion, and optical performance. The results underscore the importance of managing gel-network stability and rheology to ensure reliable green sheet fabrication and storage in MLCC manufacturing. Full article

To meet the requirements of next-generation spacecraft thermal protection systems for lightweight materials with high strength, effective thermal insulation, and superior ablation resistance, a novel POSS-modified phenolic aerogel/quartz fiber composite (POSS-PR/QF) was developed using a thiol–ene click reaction combined with a sol–gel process. Covalent incorporation of polyhedral oligomeric silsesquioxanes (POSS) into the phenolic matrix effectively eliminates nanoparticle aggregation and improves interfacial compatibility. As a result, the modified resin is suitable for resin transfer molding (RTM) processes. The resulting composite exhibited an aerogel-like porous structure with enhanced crosslinking density, thermal stability, and oxidation resistance. At 7.5 wt% POSS loading, the composite achieved low density (~0.7 g·cm⁻³) and outstanding mechanical properties, with tensile, flexural, compressive, and interlaminar shear strengths increased by 114%, 79%, 29%, and 104%, respectively. Its thermal conductivity (0.0619 W/(m·K)) and ablation rates were also markedly reduced. Mechanistic studies revealed that POSS undergoes in situ ceramification to form SiO₂ and SiC phases, which create a dense protective barrier. In addition, this ceramification process promotes char graphitization, thereby enhancing oxidation resistance and thermal insulation. This work provides a promising approach for designing lightweight, high-performance, and multifunctional thermal protection materials for aerospace applications. Full article

β-Glucan from Tibetan highland barley (THB) is an excellent edible gel polysaccharide due to its unique hypoglycemic and antioxidant activities. However, direct extraction of β-glucan from THB exhibits low yields with higher costs. Given that highland barley spent grain (BSG) is a byproduct of the brewing process and is frequently considered waste, the efficient extraction of its β-glucan could promote high-value repurposing of BSG. In this study, 2.74% β-glucan (BSG-B) was extracted from Rhizopus oryzae (R. oryzae)-fermented BSG, which is lower than those from THB (THB-B: 4.62%) yet enabled value-added utilization of BSG. The molecular weight of BSG-B was 5.24 × 10⁶ Da, which significantly increased by 124.89% compared to that of THB-B. Fourier-transform infrared (FT-IR) spectroscopy showed similar absorption peaks in BSG-B and THB-B, except for structural modifications in the β-glucan pyranose ring induced by the fermentation of R. oryzae. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicated that BSG-B possesses a more compact structure and lower aggregation heights compared to THB-B. Moreover, BSG-B demonstrated superior antioxidant capacities to THB-B in NO/DPPH/ABTS/reducing power assays, and lower apparent viscosity and oil adsorption capacity, likely attributed to the fermentation of R. oryzae. This study establishes a foundation for extracting higher-molecular-weight antioxidant β-glucan from BSG. Full article

The impact of counterion structure, especially variations in constitutional and stereochemical isomers, on the properties and performance of AABSs remains under-explored. This study investigates how structural variations, particularly the stereochemistry of diammonium cyclohexane (DACH) counterions, influence the self-assembly behavior of AABSs. Four AABSs: undecanoyl-glycine, -L-alanine, -L-valine, and -L-leucine, were paired with six DACH counterions representing cis/trans isomers of 1,2-, 1,3-, and 1,4-DACH. Critical micelle concentrations (CMCs) were determined via conductimetry, and micellar sizes were measured using dynamic light scattering. The degree of counterion binding (β) was calculated to probe micelle stability, while geometry-optimized structures of the DACH isomers were obtained using density functional theory. Lastly, pH measurements were taken to probe the protonation of DACH counterions at their natural pH, where both the DACH counterion and AABS headgroups intrinsically behave as buffers. Results indicate that while surfactant hydrophobicity primarily dictates CMC in other AABS/DACH combinations, trans-1,3-DACH leads to consistently higher CMCs. This deviation likely arises from its structural conformation, which positions the amine groups an intermediate distance of ~4.4–4.5 Å apart, allowing a small fraction of divalently charged counterions to form strong electrostatic bridging pockets at the micelle interface. These interactions dominate over headgroup effects, leading to elevated and surfactant-independent CMC values. Regarding size and other unusual trends in the systems, cis- isomers formed slightly larger micelles, and trans-1,4-DACH induces abnormal aggregation in undecanoyl-glycine leading to temperature dependent gel formation. These findings highlight the significant influence of counterion structure on AABS behavior and support counterion design as a strategy for enhancing surfactant performance in sustainable applications. Full article

This study presents an enantiomeric-ratio-driven strategy for constructing mechanically robust supramolecular gels using cyclohexane bisurea derivatives. By employing non-equimolar enantiomeric mixtures, we achieved an ultralow critical gelation concentration (CGC < 2 mg/mL) in toluene, representing a reduction of more than fivefold compared to homochiral single-enantiomer systems. Rheological measurements revealed substantially enhanced mechanical properties in the non-equimolar gels, with yield stress and storage modulus values up to 17 and 20 times higher, respectively, than those of single-enantiomer gels. Morphological analyses (SEM and POM) indicated that pure enantiomers form isolated crystalline fibers with limited connectivity, whereas racemic mixtures yield disordered amorphous aggregates. In contrast, non-equimolar mixtures self-assemble into hierarchical “sea urchin-like” architectures, wherein crystalline fibers radiate from central cores to form densely interconnected networks. This unique structural motif underpins both the ultralow CGC and superior mechanical performance. Complementary FT-IR, XRD, and DSC analyses demonstrated that chiral imbalance modulates hydrogen-bonding interactions and structural order, while molecular dynamics (MD) simulations provided insight into the divergent self-assembly pathways among homochiral, racemic, and non-equimolar systems. This work provides a stereochemically guided approach for designing high-performance supramolecular gels with tailored hierarchical structures and enhanced functionality. Full article

Recycled aggregate concrete refers to concrete made by using recycled aggregates produced from construction waste to replace natural aggregates. The performance of recycled aggregate concrete is extremely unstable. Internal factors such as water–cement ratio, porosity, and the properties of recycled aggregates, as well as external factors like temperature, humidity, environmental erosion, and the addition of improvement materials, may all have an impact on its mechanical properties. The response surface analysis method was employed to investigate the impact of three key factors—the number of dry–wet cycles, the content of stainless steel fibers, and the concentration of Na₂SO₄—on the mechanical properties of stainless steel fiber recycled aggregate concrete (SSFRAC) under dry–wet cycling conditions in the study. By incorporating stainless steel fibers into the cementitious gel network, SSFRAC is conceptualized as a composite material where the metal fibers are integrated into the gel matrix, forming a hybrid system akin to metallogels. The response models for compressive strength durability coefficient S_c and flexural strength durability coefficient S_f are established using Design-Expert software to evaluate the significance of these factors and their interactions. The version of Design-Expert used in this study is Design Expert 13.0. The results demonstrated that both S_c and S_f models exhibit high fitting accuracy, effectively capturing the relationships among the factors. The number of dry–wet cycles exhibit the highest significance, followed by Na₂SO₄ concentration and stainless steel fiber content. The interaction between dry–wet cycle number and Na₂SO₄ concentration has a particularly significant impact on S_c. For S_f, stainless steel fiber content is the most significant factor, followed by dry–wet cycle number and Na₂SO₄ concentration, with the interaction between fiber content and Na₂SO₄ concentration exerting a notably strong influence. This study highlights the potential of cement-based gels as raw materials for synthesizing functional composite materials, where the incorporation of metal fibers enhances mechanical performance and durability under aggressive environmental conditions. The findings provide insights into the design and optimization of hybrid gel–metal systems for advanced construction applications. Full article

In this study, alkali-activated materials (AAMs) were developed using finely ground coral powder (CP) and granulated blast furnace slag (GBFS) as the primary raw materials, weak alkali as the activator, and sea sand as the fine aggregate. The influence of raw material composition on the macro-mechanical properties was analyzed. Further, combined with micro-analysis techniques, the characteristics of micro-crystal formation and transformation, governed by raw material properties, and the formation and development mechanism of the enhanced micro-gel structure were elucidated. The results indicate that the activation effect of Ca(OH)₂ is significantly superior to that of Na₂CO₃. The excessively high calcium content and insufficient silicon and aluminum content in CP hinder gel formation and mechanical properties development. GBFS addition optimized the calcium-silicon-aluminum ratio and significantly improved CP reactivity. Also, compressive strength is enhanced considerably, accompanied by continuous optimization of the micro-gel structure as the GBFS content increases. At a GBFS-to-CP optimal ratio of 1:1, compressive strength of 21.8 MPa could be achieved at 28 days of age. However, the strengthening effect significantly reduced for the GBFS content > 50%. GBFS promotes the continuous formation of a zeolite-like phase gel structure, leading to a substantial improvement in compressive strength. Full article

The CaO-SiO₂-P₂O₅ system is one of the main systems studied aiming for the synthesis of new bioactive materials for bone regeneration. The interest in materials containing calcium-phosphate-silicate phases is determined by their biocompatibility, biodegradability, bioactivity, and osseointegration. The object of the present study is the synthesis by the sol-gel method of biocompatible glass-ceramics in the Ca₂SiO₄-Ca₃(PO₄)₂ subsystem with the composition 6Ca₂SiO₄·Ca₃(PO₄)₂ = Ca₁₅(PO₄)₂(SiO₄)₆. The phase-structural evolution of the samples was monitored using X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and surface area analysis. A powder (20–30 µm) glass-ceramic material containing fine crystalline aggregates of dicalcium silicate and plates of silicon-substituted hydroxyapatite was obtained after heat treatment at 700 °C. After heat treatment at 1200 °C, Ca₁₅(PO₄)₂(SiO₄)₆, silicocarnotite Ca₅(PO₄)₂(SiO₄), and pseudowollastonite CaSiO₃ were identified by XRD, and the particle size varied between 20 and 70 µm. The compact glass-ceramic obtained at 1400 °C contained Ca₂SiO₄-Ca₃(PO₄)₂ solid solutions with an α-Ca₂SiO₄ structure as a main crystalline phase. SEM showed the specific morphology of the crystalline phases and illustrated the trend of increasing particle size depending on the synthesis temperature. Effects of the glass-ceramic materials on cell viability of HL-60-derived osteoclast-like cells and on the expression of apoptotic and osteoclast-driven marker suggested that all materials at low concentrations, above 1 µg mL⁻¹, are biocompatible, and S-1400 might have a potential application as a scaffold material for bone regeneration. Full article

Moroccan oil shale ash (MOSA) represents an underutilized industrial by-product, particularly in the Rif region, where its high mineral content has often led to its neglect in value-added applications. This study highlights the successful conversion of MOSA into amorphous mesoporous silica (AS-Si) using a sol–gel process assisted by polyethylene glycol (PEG-6000) as a soft template. The resulting AS-Si material was extensively characterized to confirm its potential for environmental remediation. FTIR analysis revealed characteristic vibrational bands corresponding to Si–OH and Si–O–Si bonds, while XRD confirmed its amorphous nature with a broad diffraction peak at 2θ ≈ 22.5°. SEM imaging revealed a highly porous, sponge-like morphology composed of aggregated nanoscale particles, consistent with the nitrogen adsorption–desorption isotherm. The material exhibited a specific surface area of 68 m²/g, a maximum in the pore size distribution at a pore diameter of 2.4 nm, and a cumulative pore volume of 0.11 cm³/g for pores up to 78 nm. DLS analysis indicated an average hydrodynamic diameter of 779 nm with moderate polydispersity (PDI = 0.48), while a zeta potential of –34.10 mV confirmed good colloidal stability. Furthermore, thermogravimetric analysis (TGA) and DSC suggested the thermal stability of our amorphous silica. The adsorption performance of AS-Si was evaluated using methylene blue (MB) and ciprofloxacin (Cipro) as model pollutants. Kinetic data were best fitted by the pseudo-second-order model, while isotherm studies favored the Langmuir model, suggesting monolayer adsorption. AS-Si could be used four times for the removal of MB and Cipro. These results collectively demonstrate that AS-Si is a promising, low-cost, and sustainable adsorbent derived from Moroccan oil shale ash for the effective removal of organic contaminants from aqueous media. Full article