Search Results (707)

This study used UV-Vis absorption spectroscopy to investigate the interactions of flavonoids—baicalein (with ortho-dihydroxyl on the A-ring) and apigenin (with 4′-monohydroxyl on the B-ring)—with metal ions (Co²⁺, Ce⁴⁺) and membrane–mimetic systems (CTAB/SDS micelles, liposomes, vesicles). It revealed how flavonoid spectral properties related to molecular structure and microenvironment. Key findings were as follows: pH affected absorption spectra by altering phenolic hydroxyl protonation. Metal chelation depended on hydroxyl position: baicalein’s A-ring ortho-dihydroxyl formed a stable charge-transfer complex with Cu²⁺. In acidic medium, apigenin reduced Ce(IV) more effectively than baicalein, which contradicted the classic antioxidant role of ortho-dihydroxyl groups. This showed that reaction microenvironments could change hydroxyl reactivity and electron transfer paths. Membrane–mimetic systems (liposomes/vesicles) raised apparent pKa, enhanced solubility and stability. The study first quantified distinct ΔpKa values for different flavonoids (e.g., quercetin vs. baicalein), which were linked to intramolecular H-bonding and membrane preference. Quercetin’s B-ring ortho-dihydroxyl enabled the formation of hydrophobic interfacial anions in nanocarriers under alkaline pH, ensuring high stability. Kaempferol showed sustained leakage. These findings provided a basis for structure-guided flavonoid carrier design, bioavailability, and antioxidant delivery. By integrating reaction microenvironment, membrane interface effects, and carrier stability, this work clarified flavonoid bioactivity mechanisms and supported targeted delivery strategies. Full article

Lymphoplasmacytic gastritis (LPG) is one of the most prevalent chronic diseases affecting cheetahs (Acinonyx jubatus) under human care, yet its underlying cause remains unresolved. Gastric inflammation occurs in the majority of adult captive cheetahs but is uncommon in free-ranging populations, suggesting that management-related factors contribute to disease pathogenesis. This review proposes that LPG represents a bile acid-driven gastroenteropathy arising from disruption of the natural feeding ecology of the cheetah. In free-ranging systems, cheetahs consume large episodic meals separated by prolonged fasting intervals and ingest whole-prey containing substantial connective tissue and collagen. In captivity, feeding patterns are typically characterized by smaller, more frequent meals and diets dominated by lean skeletal muscle with reduced structural complexity. I hypothesize that this mismatch alters gastric emptying kinetics, disrupts coordinated pancreatic and biliary secretion, and destabilizes fat digestion. Inefficient lipolysis may impair micelle formation and promote bile acid mislocalization within the gastrointestinal tract, increasing mucosal exposure to hydrophobic bile acids capable of inducing chemical epithelial injury. Within this framework, lymphoplasmacytic gastritis is interpreted as a secondary inflammatory reaction to chronic bile acid-mediated mucosal stress rather than a primary immune-mediated disorder. The model also provides a mechanistic explanation for the frequent coexistence of gastritis with fat and protein maldigestion in captive cheetahs. Differential responses to antimicrobial therapy, glucocorticoids, sulfasalazine, pancreatic enzyme supplementation, and bile acid-modifying agents are broadly consistent with this proposed mechanism. Recognition of LPG as a physiologically driven gastroenteropathy has important implications for management, emphasizing restoration of feast–fast feeding patterns, inclusion of collagen-rich carcass components, and targeted modulation of bile acid composition and signaling. Full article

To enhance the overall performance of direct coal liquefaction residue (DCLR)-modified asphalt, particularly its low-temperature cracking resistance, SBS and aromatic oil were employed for composite modification. Nine composite-modified asphalt formulations were prepared based on an orthogonal experimental design. High-and low-temperature rheological properties and microstructure of all modified asphalts were systematically evaluated using a dynamic shear rheometer (DSR), a bending beam rheometer (BBR), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicate that composite modification significantly enhanced the high-temperature performance of the asphalt. Modified asphalt labeled as Sample No. 9 (9% DCLR, 4% SBS, and 6% aromatic oil) demonstrated the minimal non-recoverable creep compliance ($J_{nr}$) value of 0.58 kPa⁻¹ at 64 °C, indicating a 78.6% decrease relative to the matrix asphalt. In terms of low-temperature performance, Sample No. 3 satisfied the Superpave cracking resistance criterion, exhibiting a creep rate ($m$-value) of 0.312 at −12 °C. It was revealed by FTIR analysis that the interaction between the composite modifier and the base asphalt was mainly physical blending, and no new functional groups were generated either before or after aging. The improvement in performance was attributed to the physical compatibility and structural reorganization among the components. Microstructural analysis revealed that the uniform dispersion of modifiers in matrix asphalt and the subsequent formation of a dense micelle structure after aging contributed to the enhanced macroscopic performance. This study provides theoretical and technical support for the high-value application of DCLR in asphalt pavements. Full article

In this study, a series of amphiphilic polyether-modified silicone oil (PMSO) polymers with hydrophilic–lipophilic balance (HLB) values ranging from 3.5 to 5 were synthesized via hydrosilylation. These polymers are self-emulsifying and can form stable micelles in water without the need for external emulsifiers, with micelle sizes ranging from 79.9 to 161.4 nm. For the first time, such amphiphilic micelles were employed as an internally incorporated hydrophobic admixture to investigate the waterproofing and corrosion resistance of cement-based materials. The results showed that PMSO micelles with an HLB value of 4 significantly reduced the water absorption of cement mortar and improved mechanical properties by enhancing the compactness and crystallinity of the cement matrix. At a dosage of 0.5 wt% PMSO in mortar, the water absorption at 48 h was reduced by 50.27% compared with the control group, and the inner and outer contact angles of the mortar specimens reached 105° and 126°, respectively. The chloride diffusion coefficient of concrete decreased by 70.8% relative to the control group. At an appropriate dosage (0.1 wt%), the flexural strength of the mortar at 28 days increased by 12.50%, and the compressive strength increased by 14.19% compared with the control group. Low-field nuclear magnetic resonance (NMR) was used to determine the changes in the pore structure of mortar specimens before and after the addition of PMSO micelles. The experimental results showed that the addition of PMSO micelles reduced the number of harmful large pores, resulting in a denser microstructure. Finally, the corrosion resistance of concrete was evaluated via electrochemical accelerated-corrosion aging tests. The cracking time of concrete containing PMSO micelles was extended from 144 h (control group) to 240 h, demonstrating improved corrosion resistance. Full article

Background: Rebamipide (REB) is a poorly water-soluble drug with limited ocular bioavailability, necessitating advanced delivery strategies for sustained therapy in dry eye disease. Methods: In the present study, micelle-assisted ocular inserts were developed using non-ionic surfactants to enhance REB solubilization, drug loading, and controlled ocular delivery. The intrinsic solubility of REB in simulated tear fluid (STF, pH 7.4) was evaluated and compared with micellar systems. The formulations were characterized for particle size, polydispersity index, and zeta potential. Ocular inserts were fabricated via UV photopolymerization and evaluated for physicochemical properties, drug content, in vitro drug release, ex vivo permeation, cytocompatibility using SIRC cells, and histopathological analysis. Results: REB exhibited low intrinsic solubility in STF (26.05 ± 1.00 µg/mL), which was significantly enhanced in micellar systems, particularly with Solutol HS 15 (306.71 ± 1.10 µg/mL) and Tween 80 (263.18 ± 1.19 µg/mL). All micellar formulations formed stable nanosized micelles (7.5–15.1 nm) with low polydispersity (PDI < 0.35) and near-neutral zeta potential (−0.08 to −2.81 mV). The prepared ocular inserts showed uniform thickness, weight, and physiological surface pH. Micelle-assisted inserts demonstrated significantly higher drug content (87.40 ± 3.25 to 99.19 ± 2.44 µg/insert) compared to plain REB inserts (21.41 ± 2.28 µg/insert). In- vitro studies revealed sustained drug release over 24 h (92.25 ± 1.64 to 100.50 ± 1.10%), whereas plain inserts showed burst release. Ex vivo permeation studies indicated enhanced drug permeation (up to 77.30 ± 0.34 µg) and improved flux (1.38–8.52 µg/cm²·h) compared to plain REB. Cytocompatibility studies confirmed >90% SIRC cell viability, and histopathological analysis showed no structural damage to corneal tissue. Conclusions: Micelle-assisted ocular inserts, particularly those formulated with Solutol HS 15 and Tween 80, provide a promising platform for sustained, safe, and effective ocular delivery of Rebamipide in the management of dry eye disease. Full article

The chirality-specific study of single-walled carbon nanotubes (SWCNTs) necessitates their solution-phase processing with tip-horn sonication in the presence of a stabilizing surfactant such as sodium dodecyl sulfate (SDS), a process that has been shown to introduce sonochemical side-products such as dodecanol, dodecanal, and dodecene. This work employs single-column interactions within the overloading regime to quantitatively assess the impacts of dodecanol, dodecanal, and dodecene on the ability to purify SWCNTs using Sephacryl S-200 hydrogel. Increasing concentrations of each additive caused a corresponding decrease in the number of SWCNTs adsorbed to the gel, with a 50% reduction in SWCNT uptake realized at 0.75–1.00 mM for all three additives. Per-chirality adsorption selectivity was unaffected by relatively low additive concentration, but it was significantly hindered nearer the solubility limit of each additive. Elution efficiency from each gel was independent of additives, additive concentration, and SWCNT chirality. Mechanistically, these findings suggest the integration of each additive within the micelle structure of SDS. While the concentration of each additive introduced during tip-horn sonication is insufficient to impact gel-based SWCNT purification, the presence of dodecanol impurities within as-purchased SDS have the potential to significantly impact the purification outcome, suggesting that future studies of gel-based SWCNT purification should be carried out with SDS purified by recrystallization. Full article

A novel ocellatin-P1 isoform was isolated and purified from the skin secretion of the pepper frog Leptodactylus labyrinthicus. The crude skin secretion was fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) using a C₈ column and the peptide was subsequently purified on a reversed-phase C₁₈ column. Ocellatin-LB3 (as this isoform was named) was chemically sequenced by Edman degradation. This peptide is a linear C-terminally amidated molecule composed of 25 amino acid residues: ¹GLLDTLKGAAKNVVGGLASKVMEKL²⁵-NH₂. Synthetic ocellatin-LB3 was active against Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa and inactive against Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. In addition, the peptide reduced the Trypanosoma cruzi infection in L6 cells. At 64 µM it did not reduce erythrocytes or polymorphonuclear leukocytes, but did reduce mononuclear leukocyte counts, as detected by flow cytometry. No hemolytic activity was observed in red blood cells even at 128 µM. The peptide exhibited limited antiproliferative activity against MCF-7 and HeLa tumor cells at 128 µM. Pre-incubation with the peptide appeared to enhance N-formylmethionine-leucyl-phenylalanine (fMLP)-induced migration, indicating a potential additive or synergistic effect on human neutrophils. The three-dimensional structure of ocellatin-LB3 was investigated by circular dichroism (CD) and nuclear magnetic resonance (NMR). In the presence of sodium dodecyl sulfate (SDS), the peptide adopts an α-helical structure spanning residues Leu³–Lys²⁴, which remains largely preserved even at 95 °C. NMR Hydrogen/Deuterium (H/D) exchange experiments suggest that ocellatin-LB3 adopts a preferential orientation when interacting with SDS micelles. Based on the similarity among ocellatins, and on the physicochemical and structural properties of this peptide, a possible membrane-mediated mode of action is proposed, although this remains to be experimentally validated. Full article

Nonfat dry milk (NFDM) powder was produced by spray drying a pulsed electric field (PEF)-treated solution of 48% (m/m) evaporated skim milk (ESM) that was treated with a field strength of 20 kV/cm and specific energy of 15 kJ/L at 150 L/h. PEF treatment induced reduction to particle size for whey proteins by 8.4% and casein micelles by 11.1% and increased conductivity by 10.6%. The PEF-treated ESM solution was less viscous than the non-PEF control (14.5% lower) and sedimentation was reduced by 40%. Increases to the tapped density (1.9%), solubility (4.7%), and emulsification stability (60%) of the NFDM were observed after PEF treatment. Evaluation of protein structure indicated no modification to the secondary structure, while minor changes to the tertiary structure were observed with increased fluorescence intensity and decreased transition temperatures. The reduction in casein micelle size for the PEF-treated ESM may be associated with the movement of minerals to the aqueous solvent. This study is the first to apply PEF technology to a highly concentrated ESM solution using a continuous flow commercial PEF system. The results of this study suggest that PEF technology may be beneficial to improving the dairy processing efficiency of ESM and product quality for NFDM. Full article

Ocular fungal diseases are associated with severe infection and pain and, in advanced stages, can lead to vision loss. Current treatment options are limited to the topical application of conventional drugs, and the bioavailability of these drugs is quite limited due to ocular barriers. In this study, a dual-drug nanodelivery system was developed to improve intraocular drug delivery by combining antifungal and anti-inflammatory therapies. Posaconazole (PSC), a broad-spectrum triazole antifungal agent, and dexketoprofen trometamol (DKP), a rapidly acting nonsteroidal anti-inflammatory drug, were co-loaded onto polymeric micelles and then incorporated into electrospun poly(vinyl alcohol)/poly(vinylpyrrolidone) (PVA/PVP) nanofiber intraocular implants. DSC, XRD, FTIR, and FESEM analyses showed that both APIs were successfully converted into nanofiber form without disrupting the micelle structure. Comparative studies with DKP solution and PSC commercial oral suspension (Noxafil^® 40 mg/mL) showed that the produced micelle-loaded nanofibers provided sustained release and significantly increased ex vivo ocular permeation and penetration. In vitro antifungal activity tests demonstrated efficacy against Candida albicans, and HET-CAM toxicity tests showed that the micelle-loaded nanofibers were non-irritating and suitable for ocular application. Overall, the micelle-loaded electrospun nanofiber ocular inserts developed in this study represent a promising platform for combined antifungal and anti-inflammatory ocular therapy. Full article

Among the most structurally diverse biomacromolecules, polysaccharides have attracted increased attention as nanocarriers for precision medicine due to their inherent biocompatibility and versatility in functionalization. Molecular features, such as monomer composition, glycosidic linkages, charge density, and chemical modification, essentially determine the nanoscale assembly process of these biopolymers, as well as their biological compatibility. This review highlights the role of these properties in the assembly process of polysaccharide-based nanocarriers leading to a variety of self-assembled nanostructures, such as polyelectrolyte complexes, protein–polysaccharide complexes, amphiphilic micelles, vesicles, hybrid systems, and nanogels, which are extensively discussed throughout the review. This review also focuses on the structure–property–function relationships of nanocarriers as applied to the rapidly developing area of precision medicine, emphasizing the problems of sustainability and reproducibility. By combining the principles of molecular engineering, supramolecular assembly, and measurable properties, this work aims to present a unified view of the molecular engineering of polysaccharide-based nanocarriers for enhanced translation potential, as well as to outline a coherent framework for the rational development of next-generation polysaccharide-based nanocarriers with improved clinical relevance. Full article

Three new Mn(II) complexes with imidazo[1,2-a]pyridine derivatives were synthesized and structurally characterized in a solid state by single crystal X-ray diffraction, FT-IR and Raman spectroscopy, and thermal analyses. The investigated compounds include [Mn(3-Climpy)₂Cl₂(MeOH)₂] (1), [Mn(3-Brimpy)₂Cl₂(MeOH)₂] (2), and a rare double chloro-bridged coordination polymer [Mn(impy)₂Cl₂]_n (3). Spectroscopic studies were used to assess their potential stability in DMEM (Dulbecco’s Modified Eagle Medium), and encapsulation in Pluronic P-123 micelles improved their solubility in aqueous solution, as well as cellular uptake and selectivity. Biological evaluation revealed negligible cytotoxicity against most cancer and control cell lines, but unexpectedly high activity against pancreatic adenocarcinoma (PANC-1), exceeding that of cisplatin. Complex 2, bearing a bromine substituent in the imidazole ring, showed the strongest effects, correlating with enhanced intracellular accumulation, reactive oxygen species (ROS) generation, and mitochondrial membrane potential disruption. Molecular docking and protein binding assays demonstrated moderate affinity toward human serum albumin (HSA) and transferrin, whereas DNA interaction was weak and non-damaging. These results highlight the structure–activity relationship of Mn(II) imidazo[1,2-a]pyridine complexes and support their potential as targeted redox-active agents against pancreatic cancer, with polymeric encapsulation providing an effective strategy to enhance biological performance. Full article

Nutritionally crucial unsaturated fatty acids, especially rich in high omega-3 bonds, are very prone to oxidation. This phenomenon makes oxidation stability a substantial challenge in every formulation, especially those which contain or at some stage of preparation contain water. Bigels and emulgels, which represent promising structured lipid systems for replacing saturated and trans fats in food formulations, pose significant oxidative stability challenges. This review examines oxidation mechanisms in such biphasic systems. Oxidation in bigels and emulgels proceeds through both free-radical-mediated autoxidation and metal-ion-catalysed pathways, with the oil–water interface serving as the primary reaction zone where pro-oxidants concentrate, and lipid substrates become accessible. Structural configuration critically determines oxidative stability, following the sequence W/O bigel > bicontinuous bigel > O/W bigel. The high viscosity of gel matrices provides substantial protection by restricting radical mobility and oxygen diffusion. Mass transfer occurs via diffusion, collision–exchange–separation, and micelle-assisted mechanisms, with association colloids forming localized interfaces that accelerate oxidation. Thermal processing presents particular challenges, as temperatures above 50 °C disrupt most gel structures and accelerate oxidative degradation. Effective protective strategies include interfacial engineering with emulsifiers to reduce oil–water interfacial tension, incorporation of natural antioxidants (e.g., phenolic compounds and tocopherols), and synergistic antioxidant combinations. This review provides a mechanistic framework for formulating oxidatively stable bigels and emulgels suitable for food applications. Full article

Lipopolysaccharides (LPSs) are key components of the bacterial outer envelope, determining its structural integrity, barrier properties, and interactions with the surrounding environment. This review analyzes the relationship between the molecular architecture of LPSs and their physicochemical properties. Particular attention is being paid to the organization of LPS-containing supramolecular assemblies, including bacterial outer membranes, bilayers, micelles, and LPS brushes. The review further focuses on theoretical frameworks employed to describe LPS layers and discusses the physical meaning of the parameters involved in these models. The simulations involve a wide range of approaches starting from all-atom molecular treatment and up to polymer and colloidal approaches. When considering these models, we focus on the relationships between parameters that are addressed at each level of modeling. It is shown that biological functions such as membrane stability and bacterial adhesion are largely governed by the molecular organization of LPS. This structure–property relationship provides a basis for predicting the performance of anti-adhesive biomaterials, antimicrobial strategies, and bactericidal agents. Full article

The world population is increasing exponentially and is expected to reach 9.2 billion people by 2040, intensifying pressures on food systems and raising concerns regarding food security and environmental sustainability. In response, plant-based and microbially sourced meat and dairy analogues have emerged as alternatives to animal-derived foods. These next-generation products rely heavily on fat substitutes to replicate the sensory and functional roles of animal fats, which not only influence flavour, texture, and consumer acceptance but also play a critical role in digestion and the absorption of lipophilic nutrients. This review advances a structure–interface–digestion framework for understanding fat substitutes in meat and dairy analogues, in which lipid composition and supramolecular organization jointly determine digestive fate and nutritional functionality. Rather than acting solely as sensory replacers, fat analogues regulate lipolysis kinetics, mixed micelle formation, and the bioaccessibility of lipophilic nutrients through key parameters including fatty acid chain length, degree of saturation, physical state, and interfacial architecture. Within this framework, plant and microbially derived lipid systems are not functionally interchangeable with animal fats and therefore require purposeful structural design to ensure effective digestion and nutrient delivery. By integrating insights from food sciences, nutrition, and biotechnology, this review highlights the necessity of rationally engineered fat analogue systems that reconcile sustainability constraints with sensory performance and optimal nutritional efficacy. Full article

To improve the efficiency of injecting intensifying chemical slugs into injection wells, new formulations have been proposed. These compositions are based on high-tonnage surfactants combined with industrially produced nanoparticles. Experiments show that adding silica- or carbon-based nanoparticles to surfactant compositions doubles the oil displacement coefficient from Pashian sandstones. Carbon nanoparticles derived from shungite mineral were also tested. It was found that during the filtration of the surfactant solution, the increase in the oil displacement coefficient is always lower than during the filtration of the same solution in the presence of nanoparticles. This composition contains anionic and nonionic surfactants in a 1:2 ratio at a 1% concentration in fresh water, with a 1% nanoparticle additive. It increases the oil displacement coefficient by 19.0–23.2% after waterflooding. It has been established that in the proposed technology for near-wellbore formation treatment, the role of nanoparticles lies in a transport function due to the formation of nanoparticle aggregates with surfactant micelles, representing dynamic structures sized 25–75 μm. These aggregates break apart when passing through narrow pore throats. This delivers surfactants directly to the oil–rock interface, mobilizing residual oil and improving displacement. Nanoparticles of silica with different wettability, during filtration, are deposited in pore channels, leading to intra-pore flow redistribution. Together with the increased microscopic sweep efficiency from surfactants, it results in lower residual oil saturation. Full article