Search Results (6,399)

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

We present the observations and the results of our experience from many hours of constructing, assembling, handling, and interacting with our functional reconstruction models of the Antikythera Mechanism. The parts were constructed and the models were assembled by applying a strict Constructional Protocol for a Research Grade functional reconstruction, after a careful study of the Personal Constructional Characteristics/Design Style of the (unknown today) ancient craftsman, retracted from the mechanical parts of the Mechanism’s fragments. During the extensive use of our models, it was concluded that two important and mandatory indicators are missing from all current reconstructions of the Mechanism. The two indicators are necessary for the Antikythera Mechanism to be considered as a complete and self-contained operational time-measuring device which provided direct astronomical and calendar information without additional calculations. The two operations related to the preserved remains were located on gear b1 and its lost Cover Disc. The reconstruction of those missing parts was done according to the Constructional Protocol. The extensive analysis of the Antikythera Mechanism’s operations leads to the understanding of the Mechanism as a luni-(solar) time-measuring device, as opposed to the notion that it was a mechanical planetarium presenting the hypothesized planetary motions and positions. Full article

The synthesis of continuous non-linear metal nanostructures at the micro and nanoscale remains a challenging frontier in nanotechnology due to inherent synthetic constraints. This study introduces an innovative chemical methodology for fabricating continuous rings and diverse geometries via the chemical fusion of gold nanorods (AuNRs) on a solid substrate. Initially, aqueous solutions of cetyltrimethylammonium bromide (CTAB)-coated AuNRs were deposited and dried on a solid substrate, resulting in the self-assembly of ring-like arrays. Subsequent chemical growth of the AuNRs in all dimensions was achieved using an aqueous solution of Au(I)/CTAB/Ascorbic Acid (AA), enabling their fusion into continuous structures. This approach permits the formation of arbitrary shapes by pre-arranging AuNRs, thereby opening new avenues for the exploration of non-linear nanostructures with potentially novel plasmonic and electronic properties. The capability to engineer such complex nanostructures is pivotal for advancing fields such as photonics, electronics, and sensing, where the unique optical and electronic properties of gold nanostructures can be exploited for cutting-edge applications. Furthermore, this technique shows a significant promise for the fabrication of various micro- and nanodevices and the seamless interconnection of components in integrated electronic circuits, potentially leading to more efficient and miniaturized electronic systems. The broader implications of this research are significant, offering a potential pathway to the development of nanomaterials and devices that could benefit various industries and technological processes. Full article

Up to now, most hydrogel-related studies have been devoted to the preparation of drug-containing macromolecular gels via the introduction of polymer matrices, together with the clarification of their assembly mechanisms and biomedical applications. In contrast, studies concerning the design of small-molecule gel systems remain relatively limited. As gel research progresses, drug small-molecule hydrogels have attracted growing interest for formulation development. This study investigated whether designing a small-molecule hydrogel could serve as an effective solubilization approach for sulindac (SUL)—a nonsteroidal anti-inflammatory drug clinically restricted by its poor aqueous solubility. Then, a SUL small-molecule hydrogel was prepared by straightforward mixing of SUL with biologically safe meglumine (MEG) in a minimal volume of deionized water, which exhibited a characteristic three-dimensional network structure and favorable viscoelastic properties. The characterization and simulation results indicated that the hydrogel formation was contingent upon the SUL-MEG miscibility, dissolution-aggregation equilibrium and intermolecular self-assembly. Consequently, the resulting SUL-MEG hydrogel exhibited 546 times higher solubility compared to the pure SUL. Meanwhile, the SUL-MEG hydrogel demonstrated superior release kinetics and supersaturation capacity, characterized by rapid attainment of peak concentrations and sustained supersaturated release. These enhanced performances were attributed to the high-energy state of the hydrogel itself and the molecular complexation between SUL and MEG. In conclusion, this study presents a feasible formulation strategy for overcoming the poor water solubility of insoluble drugs through the development of small-molecule hydrogel formulations. Full article

Mesoporous bioactive glasses (MBGs) represent a significant advancement in bioactive glass technology, combining the well-established osteoconductive and osteoinductive properties of traditional bioactive glasses with the structural precision provided by highly ordered mesoporosity. Their characteristic architecture, defined by uniform pores typically ranging from a few to several tens of nanometers and exceptionally high surface areas reaching several hundred m²/g, enables enhanced drug-loading capacity, controlled therapeutic ion release, and accelerated tissue regeneration. In this work, we emphasize how the synthesis of these materials is predominantly governed by structure-directing agents, which critically influence the pore size, mesophase ordering, surface area, and structural stability. Additionally, we discuss how compositional tailoring, particularly through therapeutic ion doping with elements such as Sr, Cu, Zn, or B, can impart osteogenic, angiogenic, antibacterial, or antioxidant functionalities. Moreover, we illustrate how these functionalities can be further expanded and enhanced by employing a comprehensive suite of characterization tools to establish robust correlations between synthesis parameters, mesostructural features, and biological performance. Improving the above functionalities enables the MBGs to exhibit exceptional versatility across biomedical applications, notably in bone tissue engineering (as hierarchical or composite scaffolds), controlled drug delivery (anticancer, antibiotic, and anti-inflammatory agents), wound healing, dental therapy, and bioactive implant coatings. Finally, we acknowledge that despite their broad potential, several associated challenges remain, including the synthesis scalability, batch-to-batch reproducibility, mechanical fragility of pure MBGs, and the complexity of predicting in vivo degradation and ion-release behaviors. We believe that emerging research directions, including eco-friendly synthesis routes, stimuli-responsive smart MBGs, multifunctional theranostic platforms, and patient-specific additive manufacturing, are poised to overcome current limitations and drive the next generation of MBG-based biomedical technologies. Full article

Eight H-bonded salts of arsenic acid and nitrogen bases (2,4,6-trimethylpyridine, pyridine-2,6-diamine, pyridin-4-ol, 4-methoxypyridine, 4-methoxyaniline, 1,3,5-triazine-2,4,6-triamine, diethylamine and N¹,N¹,N²,N²-tetraethylethane-1,2-diamine) were studied in the solid state by single crystal X-ray diffraction technique and DFT calculations. In all cases quite short (≤2.65 Å) OHO bonds were found in the self-assembled supramolecular ribbons or 2D networks of dihydrogen arsenates, constituting a repertoire of five different H-bonding patterns (motifs). The electron localization function maps revealed the spots of the nucleophilic sites on oxygen atoms that determine the preferable directions for H-bonding of H₂AsO₄⁻ anions observed in the crystal packing. Analysis of the electrostatic potential maps for isolated species has demonstrated that upon H-bonding between H₂AsO₄⁻ anions and protonated nitrogen bases, NH⁺⋯⁻OAsO(OH)₂, the redistribution of electron density within the anion provides otherwise virtually non-existent electrophilic sites on hydrogen atoms, which balances the Coulomb repulsion and allows for the anion⋯anion pairing within the crystal. The topological analysis of the calculated crystalline electron density after relaxation of the hydrogen atoms’ positions was used to classify the OHO bonds as moderately strong ones (with an interaction energy up to 65 kJ/mol) and revealed a high degree of ionicity of molecular moieties within ion pairs (with an absolute charge up to 0.87 e). For the strongest OHO and NHO bonds, the noticeable covalent character was shown by using the crystal orbital Hamiltonian population analysis. Full article

Background/Objectives: Alzheimer’s disease (AD) has an irreversible disease course, making early intervention a key measure to delay disease progression. However, existing therapies are limited by weak brain-targeted delivery efficiency due to the blood–brain barrier (BBB) and low bioavailability of drugs, making it difficult to address the complexity of AD’s pathological mechanisms. Methods: Addressing these limiting factors, this research aims to develop an early AD intervention formulation with “high targeting, high bioavailability, and high biosafety.” Based on the principle of drug synergistic effects, this study employed the reverse solvent method and optimized the combination ratio of Ginsenoside Rg3 and Naringenin (Nar) to design and prepare a self-assembling nano-delivery system (Rg3-Nar-NPs, GNN). The study utilized intranasal administration to bypass the BBB through the direct pathway between the nasal mucosa and central nervous system. Results: This approach enabled targeted accumulation of the drug in brain lesion areas, significantly reducing Aβ deposition, oxidative stress, and inflammatory factor surges caused by early AD, thereby improving cognitive dysfunction in mice. Moreover, GNN demonstrated superior biosafety and bioavailability compared to the individual components. Through transcriptomic analysis, the study elucidated for the first time that GNN can activate the OXT/ERK/Fos pathway to break the malignant cycle of ROS–neuroinflammation, inhibiting the amplification effect of early AD pathological damage. Conclusions: This research provides new molecular targets and drug options for multi-target synergistic intervention of early AD, showing potential as a candidate strategy for precise early AD intervention and laying theoretical and experimental foundations for subsequent clinical translation. Full article

Magnetic metals are of considerable importance for stealth technology and electromagnetic pollution control. However, they suffer from inherent limitations, such as the Snoek limit and narrow absorption bandwidth, which restrict their applications in complex scenarios. To address these challenges, this review systematically summarizes the recent advances of magnetic metal-based microwave-absorbing materials (MAMs), focusing on four core directions: alloy design, composite engineering, structural regulation, and preparation technology. The intensity and frequency bands of absorption in alloys are dictated by the material’s composition as well as its structural attributes. Moreover, composite systems incorporating carbon materials, MXenes, oxides, ceramics, and conductive polymers are discussed, where the synergistic design of components optimizes impedance matching and loss mechanisms. Key structural design strategies include core-shell structures, interface engineering, self-assembled hierarchical structures, and macroscopic structural design. These structures achieve the synergistic improvement of thin, lightweight, broadband, and strong absorption performance by enhancing interface polarization, multiple scattering, and resonance effects, while endowing materials with excellent environmental stability. Notably, metamaterial-based designs can further achieve an ultrawide bandwidth spanning 0.3–18 GHz. Additionally, preparation processes are crucial for regulating the microstructure and activating loss mechanisms. This review aims to offer theoretical and practical insights for developing high-performance, multifunctional magnetic MAMs. Full article

Graphoepitaxy provides a robust route to align lamellar block copolymers in topographic trenches, yet alignment often degrades rapidly as the trench width increases into the wide-trench regime. Here, mesoscale density functional simulations under thermal annealing are used to quantify width- and geometry-dependent ordering of symmetric lamella-forming block copolymers confined in trenches. A Fourier-based alignment metric reveals a sharp, sigmoidal decay of alignment with trench width normalized by the natural lamellar period, indicating a crossover between (i) a globally aligned state established by wall-guided propagation and (ii) a misoriented, kinetically trapped state produced by bulk-like interior nucleation followed by domain impingement. This width dependence is well captured by a logistic form, yielding a characteristic crossover width and transition sharpness that compactly describe the accessible alignment window. Parameter sweeps show that increasing incompatibility shifts the crossover to smaller widths, whereas stronger sidewall surface fields extend the accessible width range with diminishing returns at large fields; in the range examined, film thickness has little influence on the crossover. Finally, simulations in trapezoidal trenches demonstrate that high alignment persists for moderate sidewall taper, while larger taper promotes lamellar bending and defects. A geometric criterion based on the variation in trench width across the film thickness, using a numerical threshold derived from strong-segregation theory, rationalizes the observed onset of degradation when this variation approaches approximately 1.4 lamellar periods. These results provide a mechanistic framework and quantitative guidelines for extending graphoepitaxial lamellar alignment beyond the narrow-confinement regime. Full article

This study reports the synthesis and catalytic evaluation of a series of imidazolium-based polymeric ionic liquids (PILs) for the cycloaddition of CO₂ to epichlorohydrin (ECH). The synthesized catalysts include homopolymers, poly(3-hydroxyethyl-1-vinylimidazole chloride) (p[HVIm][Cl]) and poly(3-carboxymethyl-1-vinylimidazole chloride) (p[CMVIm][Cl]), and their block copolymers with polystyrene, synthesized for the first time, pS-b-p[HVIm][Cl] and pS-b-p[CMVIm][Cl]. Structural characterization by NMR, IR spectroscopy, and gel permeation chromatography confirmed the successful synthesis. The block copolymers exhibited a low polydispersity index (PDI 1.1–1.2), which is indicative of homogeneous chain lengths and the propensity to form ordered nanostructures, whereas the homopolymers showed higher PDI (2.4–2.9). Catalytic testing at 90 °C and 1 MPa CO₂ for 4 h revealed a clear activity trend: p[CMVIm][Cl] < p[HVIm][Cl] < pS-b-p[CMVIm][Cl] < pS-b-p[HVIm][Cl], with conversions exceeding 75% for all catalysts and a maximum of 82.69% for pS-b-p[HVIm][Cl]. These results demonstrate that the catalytic performance of PILs is governed by a synergistic interplay between the local chemical functionality of the ionic moiety and the overall polymer architecture. Based on these results, the synthesized polymeric ionic liquids, particularly pS-b-p[HVIm][Cl], demonstrate strong potential for creating multifunctional materials. Their ability to self-assemble into ordered nanostructures with distinct hydrophobic and hydrophilic domains provides a foundational architecture for combined gas separation and catalysis. The observed “micellar catalytic effect”, which enhances local reagent concentration near active sites, could be leveraged in a membrane reactor to simultaneously capture and convert CO₂ directly within the membrane. This integrated “separation–reaction” approach represents a promising strategy for advancing circular carbon economy technologies. Full article

The immersive, multisensory experiences offered by virtual reality have been transformative across multiple disciplines, enhancing practical and theoretical skills while increasing user motivation and learning. On the other hand, multi-agent systems have proven to be effective in facilitating the expansion and modularity of computer systems. This paper presents an application developed in a virtual reality environment based on multi-agent systems for the conceptual design of mechanical assemblies from primitives. As a main novelty, the primitives can be defined by the user of the application from a set of models and images, and an Excel document, without the need for programming knowledge, taking advantage of the possibilities offered by multi-agent systems. In addition, for each primitive, it is possible to define a set of geometric and dimensional modifications, as well as a set of position relations with respect to other primitives to generate mechanical assemblies. Full article

Gene delivery/administration and, in particular, small interfering RNA (siRNA) delivery represent a therapeutic challenge, though very effective carriers have yet to be identified. Cyclodextrins (CDs) are cyclic oligosaccharides with unique host–guest inclusion capabilities, widely recognized in the pharmaceutical field for their ability to enhance drug solubility and bioavailability. Their excellent biocompatibility and chemical versatility make them powerful building blocks for the design of supramolecular nanovectors (NVs). Thanks to their facility of functionalization, CDs are highly versatile and have found numerous applications across various fields. In this context, CD-based NVs are currently explored as non-viral agents to transport and release siRNA. Recent studies suggest that self-assembled NVs based on CDs can improve the transfection and safety of siRNA delivery. This review provides a comprehensive overview of the most recent advances in the design of NVs based on CDs and their use for siRNA delivery, discussing the role played by structural differences and chemical functionalization in the context of encapsulation and release. Full article

The spontaneous emergence of macroscopic dissipative structures in systems driven by generalized chemical potentials is well established in non-equilibrium thermodynamics. Examples include atmospheric/oceanic currents, hurricanes and tornadoes, Rayleigh–Bénard convection cells and reaction–diffusion patterns. Less well recognized, however, are microscopic dissipative structures that form when the driving potential excites internal molecular degrees of freedom (electronic states and nuclear coordinates), typically via high-energy photons or coupling with ATP. Examples include dynamic nanoscale lipid rafts, kinesin or dynein motors along microtubules, and spatiotemporal Ca²⁺ signaling waves propagating through the cytoplasm. The thermodynamic dissipation theory of the origin of life asserts that the core biomolecules of all three domains of life originated as self-organized molecular dissipative structures—chromophores or pigments—that proliferated on the Archean ocean surface to absorb and dissipate the intense “soft” UV-C (205–280 nm) and UV-B (280–315 nm) solar flux into heat. Thermodynamic coupling to ancillary antenna and surface-anchoring molecules subsequently increased photon dissipation and enabled more complex dissipative processes, including photosynthesis, to dissipate lower-energy but higher-intensity UV-A and visible light. Further thermodynamic coupling to abiotic geophysical cycles (e.g., the water cycle, winds, and ocean currents) ultimately led to today’s biosphere, efficiently dissipating the incident solar spectrum well into the infrared. This paper reviews historical considerations of UV light in life’s origin and our proposal of UV-C molecular dissipative structuring of three classes of fundamental biomolecules: nucleobases, fatty acids, and pigments. Increases in structural complexity and assembly into larger complexes are shown to be driven by the thermodynamic imperative of enhancing solar photon dissipation. We conclude that thermodynamic selection of dissipative structures, rather than Darwinian natural selection, is the fundamental creative force in biology at all levels of hierarchy. Full article

α-Synuclein (α-syn) aggregation underlies synucleinopathies, yet the physicochemical determinants that govern which assembly states form under defined solution conditions remain incompletely resolved. Here, we examine how pH and metal ions reshape α-syn self-assembly. Across acidic and physiological pH conditions, α-syn populates monomeric, nanoscale oligomeric, and mesoscale aggregate states whose relative abundances evolve over time. Fluorescence microscopy reveals robust mesoscale assembly at pH 5, minimal aggregation at pH 7, and transient assemblies at pH 3, highlighting the limitations of imaging-based detection alone. Therefore, we use dynamic light scattering (DLS) to resolve oligomeric populations and quantify pH-dependent redistribution of assembly mass. Toxicity-mitigating modulators altered α-syn assembly in a strongly pH-dependent manner. Anle138b increased the abundance of oligomeric species at low pH, whereas EGCG produced divergent effects at pH 5 and pH 3. We further examined the effects of metal ions, finding that Fe³⁺ stabilized higher-order assemblies under acidic conditions, Cu²⁺ delayed assembly at pH 5 while enhancing aggregation at pH 3, and Zn²⁺ increased oligomerization primarily at low pH. Overall, these results demonstrate that α-syn assembly is highly sensitive to coupled effects of pH, metal chemistry, and time. Full article

Amphiphilic copolymers based on polystyrene and polyglycidol combine the chemical inertness of polystyrene with the biocompatibility of polyglycidol, making them attractive materials for polymeric micelles. While comb-like architectures have been explored to control micellization behavior and biological response, a direct comparison between comb-like and coil-comb topologies in polystyrene–polyglycidol copolymers at identical polyglycidol content remains insufficiently investigated. In this work, amphiphilic comb-like and coil-comb polystyrene–polyglycidol copolymers were synthesized via copper-catalyzed azide–alkyne click chemistry by grafting a monoalkyne-terminated polyglycidol precursor onto azide-functionalized random and block styrene copolymers. The copolymers were characterized by size exclusion chromatography and nuclear magnetic resonance. Polymeric micelles were prepared by nanoprecipitation, and their self-assembly in aqueous solution was investigated by critical micelle concentration determination, dynamic and electrophoretic light scattering, and atomic force microscopy. Both copolymers formed stable aqueous dispersions and exhibited comparable critical micelle concentrations. At identical polyglycidol content, the random copolymer formed a uniform, monomodal micellar population, whereas the block-based coil-comb architecture led to bimodal size distributions, indicating the coexistence of two distinct micellar populations. The investigated systems showed low cytotoxicity and did not induce significant oxidative stress within the studied concentration range. On isolated rat brain sub-cellular fractions (synaptosomes, mitochondria and microsomes), administered alone, the comb-like and coil-comb polystyrene-polyglycidol copolymers did not reveal statistically significant neurotoxic effects. The results demonstrate that macromolecular architecture plays a key role in governing micellar organization and in vitro biological response in polystyrene–polyglycidol copolymers, highlighting their potential as architecture-controlled polymer-based nanocarriers. Full article