Search Results (75)

This work describes the straightforward synthesis of a novel heterogeneous palladium catalyst immobilized on magnetic Janus-type silica particles coated with an amphiphilic ionic liquid (IL) layer. The material was prepared via a one-pot process wherein TEOS (tetraethoxysilane) and a bis(triethoxysilane) IL precursor are combined to form hollow shells. The IL motifs are selectively located on the outer surface of the hollow particles and serve as centers for the immobilization of palladium species on the material’s surface. The outer surface also hosts magnetic nanoparticles in close proximity to the palladium sites. Thanks to the uniform coverage of the surface with the amphiphilic IL functionality, the material exhibits a well-balanced wettability with reaction components of different polarities. The catalyst’s activity was tested in the Sonogashira cross-coupling reaction of terminal acetylenes and iodobenzene derivatives in water as the solvent. The results show that the mixed palladium–iron oxide catalyst exhibits higher activity than materials containing either immobilized palladium or iron oxide alone, suggesting a synergistic effect in this reaction. Additionally, the reaction proceeds well in the absence of expensive organic ligands and commonly employed additives such as copper co-catalysts or phase transfer catalysts. Furthermore, the material was also used in the oxidative Sonogashira coupling reaction of phenylboronic acid and phenylacetylene. The catalyst can be easily separated using an external magnet and can be reused several times. The feasibility of producing diphenylacetylene on a gram scale via the Sonogashira cross-coupling reaction was also investigated. Full article

This article presents the design, synthesis and application of novel C₈/PW₁₂O₄₀³⁻-IL Janus for highly efficient, recyclable catalytic degradation of methyl orange (MO) in wastewater. The catalyst’s innovative asymmetric architecture comprises a hydrophobic C₈ hemisphere that selectively adsorbs and pre-concentrates MO molecules and a catalytic phosphotungstate-based ionic liquid hemisphere that activates oxidants to generate hydroxyl radicals for rapid dye degradation. A magnetic Fe₃O₄ core facilitates instantaneous catalyst recovery. This “collect, degrade, and separate” mechanism synergistically results in exceptional performance, surpassing that of many conventional homogeneous and heterogeneous systems, as validated through comparative analysis. This work establishes a strategic paradigm for designing smart, multifunctional materials that combine targeted interfacial engineering with practical recyclability for advanced environmental remediation. Full article

Background: Both clinical and research data support the contribution of IL6-mediated local immunosuppression coupled with IL6-initiated protumorigenic processes, e.g., sustained proliferation and angiogenesis in the development of many cancers, including lung cancer. By virtue of their pharmacologic advantage, controlled release, local delivery formulations can provide immunochemopreventive relevant agent levels at the target site with negligible systemic agent-related effects. Bioavailability is a major challenge with chemopreventive agents. Methods: Janus nanoparticles (JNPs), however, are a versatile drug delivery platform that addresses several major cancer preventive challenges including bioavailability and retention of bioactivity, with elimination of potential deleterious effects with systemic administration. Furthermore, JNPs feature two discrete compartments that enable concurrent delivery of two chemically distinct agents with complementary mechanisms of action. Results: Our data show that the synthetic vitamin A derivative, fenretinide (4HPR), and the IL6R inhibitor, tocilizumab (TCZ), inhibit pathways integral for the development of lung cancer. Initial molecular modeling and kinase activity assays confirmed that 4HPR serves as a competitive inhibitor for active-site ATP binding of two key IL6 downstream kinases (JAK1, CK2). Concurrent RNA-seq analyses that employed Qiagen Ingenuity Pathway Analysis showed significant inhibition of canonical pathways associated with DNA replication and division in conjunction with significant activation of immunogeneic cell death and TREM 1 signaling pathways and showed the immune-augmenting, cancer-preventive impact of 4HPR-TCZ treatment on gene expression in premalignant lung epithelial cells. Subsequent qRT-PCR analyses corroborated the RNA seq findings and demonstrated 3- to 6-fold increased expression of TREM 1 and immunogenic cell death genes, such as TREM1 and NLRC4 and HSPA6 and DDTT3, respectively. These data collectively guided the development of human serum albumin–chitosan JNPs for the co-delivery of 4HPR and TCZ, respectively. 4HPR-TCZ JNP characterization studies demonstrated high circularities and stability in suspension, as shown by consistency in diameter and minimal changes to the polydispersity index, while confocal microscopy confirmed their biocompartmental nature. Subsequent tertiary chemoprevention in vivo studies that employed a highly aggressive human lung cancer cell line showed that JNPs releasing 4HPR and 4HPR-TCZ significantly reduced tumor volume, as assessed by vital tumor tissue, suppressed proliferation, increased apoptosis, and promoted intratumor vascular instability. Conclusions: Collectively, these studies elucidate 4HPR-TCZ in vitro chemopreventive mechanisms of action and demonstrate proof of concept for JNP-4HPR-TCZ in vivo efficacy. Full article

Janus nanoparticles (JNPs) extend the concept of amphiphilicity beyond classical molecular surfactants into the nanoscale. Amphiphilic behavior is defined by the presence of hydrophobic and hydrophilic moieties within a single molecular structure. Traditionally, such molecular structures are known as surfactants or amphiphiles and are capable of reducing interfacial tension, adsorbing spontaneously at interfaces, stabilizing emulsions and foams, and forming micelles, bilayers, or vesicles. Recent experimental, theoretical, and computational studies demonstrate that these behaviors are scalable to nanostructured colloids such as JNPs. Amphiphilic JNPs, defined by anisotropic surface chemistry on distinct hemispheres, display interfacial activity driven by directional wetting, variable interfacial immersion depth, and strong interfacial anchoring. They can stabilize liquid/liquid and liquid/gas interfaces, and enable templated or spontaneous self-assembly into supra-structures, such as monolayer sheets, vesicles, capsules, etc., both in bulk and at interfaces. Their behavior mimics the “soft” molecular amphiphiles but also includes additional particularities given by their “hard” structure, as well as contributions from capillary, van der Waals, hydrophobic, and shape-dependent forces. This review focuses on compiling the evidence supporting amphiphilicity as a scalable property, discussing how JNPs function as colloidal amphiphiles and how geometry, polarity contrast, interfacial interactions, and environmental parameters influence their behavior. By comparing surfactant behavior and JNP assembly, this work aims to clarify the transferable principles, the knowledge gap, as well as the emergent properties associated with amphiphilic Janus colloids. Full article

In order to improve oil recovery efficiency in low-permeability reservoirs, this study developed amphiphilic Janus-SiO₂ nanoparticles to prepare polymer gel microspheres for enhanced oil recovery (EOR). Firstly, Janus-SiO₂ nanoparticles were synthesized via surface modification using (3-aminopropyl)triethoxysilane and α-bromoisobutyryl bromide. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) characterization confirmed the successful grafting of amino and styrene chains, with the particle size increasing from 23.8 nm to 32.9 nm while maintaining good dispersion stability. The Janus nanoparticles exhibited high interfacial activity, reducing the oil–water interfacial tension to 0.095 mN/m and converting the rock surface wettability from oil-wet (15.4°) to strongly water-wet (120.6°), thereby significantly enhancing the oil stripping efficiency. Then, polymer gel microspheres were prepared by reversed-phase emulsion polymerization using Janus-SiO₂ nanoparticles as emulsifiers. When the concentration range of nanoparticles was 0.1–0.5 wt%, the particle size range of polymer gel microspheres was 316.4–562.7 nm. Polymer gel microspheres prepared with a high concentration of Janus-SiO₂ nanoparticles can ensure the moderate swelling capacity of the particles under high-temperature and high-salinity conditions. At the same time, it can also improve the mechanical strength and shear resistance of the microspheres. Core displacement experiments confirmed the dual synergistic effect of this system. Polymer gel microspheres can effectively plug high-permeability zones and improve sweep volume, while Janus-SiO₂ nanoparticles enhance oil displacement efficiency. Ultimately, this system achieved an incremental oil recovery of 19.72%, exceeding that of conventional polymer microsphere systems by more than 5.96%. The proposed method provides a promising strategy for improving oil recovery in low-permeability heterogeneous reservoir development. Full article

We investigated the morphological patterns, crystalline structures and their thermal stability in solidified Au–Ge nanoparticles ranging in size from 10 to 500 nm. Liquid Au–Ge alloy nanoparticles with hypoeutectic composition were rapidly cooled from a temperature of 500 °C in a TEM and characterized using advanced TEM techniques. We demonstrated that Au–Ge nanoparticles 10–80 nm in size predominantly solidified into a Janus-like morphology with nearly pure single-crystalline hcp Au and diamond cubic Ge domains. These particles remained stable up to the eutectic temperature, indicating that Ge doping and particle size play key roles in stabilizing the hcp Au phase. In turn, larger nanoparticles exhibited a metastable core–shell morphology with polycrystalline Ge shell and hcp Au-Ge alloy core under solidification. It was shown that the mentioned morphology and crystalline structure evolved into the equilibrium Janus morphology with fcc Au and diamond Ge domains at temperatures above ≈160 °C. Full article

Advanced oxidation processes (AOPs) show significant promise to degrade recalcitrant water contaminants, such as 1,4-dioxane, but slow degradation kinetics limit the energy efficiency of this technology. We realized substantial enhancements in the degradation of 1,4-dioxane (a suspected carcinogen) using gold-coated titanium dioxide (Au/TiO₂) Janus nanoparticles (JNPs) irradiated with above-bandgap ultraviolet (UV) light (peak wavelength, 254 nm). To explain this result, we combined experimental measurements quantifying 1,4-dioxane degradation at varying UV wavelengths with finite-element simulations that provided explanatory insight into the light–matter interactions at play. The enhanced photocatalytic activity at the optimal condition (254 nm light, high intensity, Au/TiO₂) resulted from a larger quantity of photogenerated holes in the TiO₂ capable of reacting with water to form hydroxyl radicals that degrade 1,4-dioxane. This increased production of holes resulted from two sources: (1) more viable electron–hole pairs were created under 254 nm light owing to increased light absorption by the TiO₂ that was localized near the surface; (2) the metal sequestered photogenerated electrons from the TiO₂, which prevented electron–hole pairs from recombining, leaving more holes available to react with water. Our results motivate the exploration of different metal coatings (especially non-precious metals) and suggest a path toward broader implementation of TiO₂-based photocatalytic AOPs, which can effectively remove many water pollutants that survive conventional treatment techniques. Full article

This study presents a multilayer magnetic Janus sub-micrometric particle (MMJSP) as a nanoreactor for lipase catalysis. The core of the nanoparticle is constructed from a core-shell Fe₃O₄@SiO₂ framework, which serves as a precursor for the sequential amino and aldehyde modifications using 3-aminopropyltriethoxysilane and benzaldehyde. Following localized etching and subsequent modification with N,N-dimethyldodecylamine, a Janus nanoparticle with distinct hydrophilic and hydrophobic domains is synthesized. The resulting MMJSP demonstrates a stable attachment to the reaction interface and significantly enhances lipase performance, exhibiting 1.4-fold and 1.6-fold enhancements in activity after immobilization during 1 h hydrolysis and 24 h esterification reactions, respectively. Additionally, the storage stability of the immobilized lipase is improved by 100% over a period of 30 days. Reusability assessments reveal that the immobilized enzyme retains 80.7% activity after 10 cycles of esterification and 80.6% after 50 cycles of hydrolysis, with the magnetic properties allowing for rapid separation and recovery of the immobilized enzyme. Full article

Developing an oral fibrous barrier membrane that prevents bacterial invasion while possessing antibacterial properties and facilitating fluid decompression remains a significant clinical and scientific challenge. In this study, we developed a novel Janus membrane by modifying a polypropylene (PP) fibrous membrane with dopamine and zinc oxide nanoparticles (ZnO-NPs). Fabricated via a simple floating immersion method, this asymmetric bilayer structure consists of a hydrophobic PP layer and a hydrophilic PP/dopamine@30 nm ZnO layer, providing both antibacterial properties and enhanced fluid filtration. The mechanical properties of the PP/ZnO membrane were significantly enhanced, with an increase in the Young’s modulus and ultimate tensile strength, indicating improved strength. Antibacterial activity against Streptococcus mutans (S. mutans) demonstrated a significant reduction in biofilm formation on the PP/dopamine@30 nm ZnO surface compared to unmodified PP. Water flux tests confirmed a stable, high filtration rate, with increased permeability under rising pressure. In vivo experiments with miniature pigs confirmed reduced bacterial presence on the sterile side of the membrane. These findings highlight the potential of the membrane for oral exudate filtration, extending filtration time and minimizing infection risks under strict sterility conditions. Further improvements in barrier properties are necessary to optimize its clinical performance. Full article

Psoriasis is a chronic inflammatory disease with a complex pathogenesis, influenced by various factors involving environment, genes, and immunity. The main symptoms of psoriasis include erythema, scales, itching, etc. At present, therapeutic drugs for psoriasis are continually evolving towards enhancing treatment efficacy and reducing side effects. Firstly, the pathogenesis and characteristics of psoriasis were summarized. Then, the types and benefits of topical therapy were introduced, such as the aspects of avoiding systemic toxic effects, first pass effect, and gastrointestinal reactions with accelerating the onset time of the drugs and improving its efficacy, and were compared to systemic drugs. In the case of methotrexate, cyclosporin A, Janus kinase (JAK) inhibitors, and phosphodiesterase-4 (PDE-4) inhibitors, this review had a further discussion on the improvement and translation of these molecules from systemic therapy to topical therapy in clinical practice. To further augment the limitation of skin permeability, nanotechnology and novel topical drug delivery system including nanomedicines, hydrogels, ionic liquids, and microneedles were elaborated for psoriasis management. Also, exploration of topical targeting pathogenic genes through small interfering RNA (siRNA) using nanoparticles and ionic liquids (ILs) is of great significance for long-term treatment in psoriasis. Taken together, the development of numerous topical delivery platforms is expected to achieve enhanced penetration, and precise and efficient delivery of small molecule and RNA interference (RNAi) therapeutics in psoriasis with clinical translation prospects. Full article

Neurocognitive impairment is an important cause of HIV-associated morbidity. The advent of antiretroviral therapy (ART) has shifted the spectrum of HIV-associated cognitive impairment from HIV-associated dementia to milder forms of cognitive impairment. Independent replication of HIV within the central nervous system in those on effective ART with peripheral suppression is a recognised phenomenon known as cerebrospinal fluid (CSF) HIV RNA escape. CSF HIV RNA escape is independently associated with neurocognitive impairment but has also been detected in asymptomatic persons with HIV. The current consensus for management of CSF HIV RNA escape is based on expert opinion rather than empirical evidence. The current evidence suggests having a low threshold to investigate for CSF HIV RNA escape and optimising ART based on resistance profiles. The use of central nervous system (CNS) penetration effectiveness scores is no longer recommended. The evidence for statins, SSRIs, minocycline, lithium and valproate is limited to small-scale studies. There are potential new developments in the form of nanoparticles, Janus Kinase inhibitors and latency reversal agents. Full article

Aluminum nanoparticles (Al NPs) are interesting for energetic and plasmonic applications due to their enhanced size-dependent properties. Passivating the surface of these particles is necessary to avoid forming a native oxide layer, which can degrade energetic and optical characteristics. This work utilized a radiofrequency (RF)-driven capacitively coupled argon/hydrogen plasma to form surface-modified Al NPs from aluminum trichloride (AlCl₃) vapor and 5% silane in argon (dilute SiH₄). Varying the power and dilute SiH₄ flow rate in the afterglow of the plasma led to the formation of varying nanoparticle morphologies: Al–SiO₂ core–shell, Si–Al₂O₃ core–shell, and Al–Si Janus particles. Scanning transmission electron microscopy with a high-angle annular dark-field detector (STEM-HAADF) and energy-dispersive X-ray spectroscopy (EDS) were employed for characterization. The surfaces of the nanoparticles and sample composition were characterized and found to be sensitive to changes in RF power input and dilute SiH₄ flow rate. This work demonstrates a tunable range of Al–SiO₂ core–shell nanoparticles where the Al-to-Si ratio could be varied by changing the plasma parameters. Thermal analysis measurements performed on plasma-synthesized Al, crystalline Si, and Al–SiO₂ samples are compared to those from a commercially available 80 nm Al nanopowder. Core–shell particles exhibit an increase in oxidation temperature from 535 °C for Al to 585 °C for Al–SiO₂. This all-gas-phase synthesis approach offers a simple preparation method to produce high-purity heterostructured Al NPs. Full article

Anisotropic particles have a wide range of applications in materials science such as emulsion stabilization, oil–water separation, and catalysis due to their asymmetric structure and properties. Nevertheless, designing and synthesizing large quantities of anisotropic particles with controlled morphologies continue to present considerable challenges. In this study, we successfully synthesized anisotropic microspheres using a soap-free seed emulsion polymerization method. This approach combines the benefits of seed emulsion polymerization with emulsion interfacial polymerization. By varying the concentrations of dissolved polymeric monomers, 3-methacryloyloxypropyltrimethoxysilane (MPS), and the initiator of potassium persulfate (KPS), different shapes of bowl, cap, and three-sided concave particles were obtained in surfactant-free aqueous solutions, simplifying the post-treatment process. The cap particles are Janus particles with good emulsion stability to toluene/water emulsions over 30 days. The catalytic degradation of 4-nitrophenol (4-NP) was investigated after loading silver nanoparticles on the surface of the particles by in situ deposition. The anisotropic particles obtained in this work have potential applications in emulsion stabilization and catalysis. Full article

This study compares the mobility behaviour, in a H₂O₂ environment, of three different geometries of hybrid particle made of silica core functionalized by gold (nanoparticles or layer). It is known that the decomposition of H₂O₂ on gold surfaces drives mobility; however, the link between mobility orientation and the organization of gold on silica surfaces is still questionable. While conventional wisdom posits that asymmetric designs are crucial for generating phoretic forces or localized bubble propulsion, recent research suggests that symmetrical particles may also exhibit motility. To address this debate, we developed a robust workflow for synthesizing gold grafted silica nanoparticles with precise control over size and shape, enabling the direct comparison of their motile behaviour by dynamic light scattering and particle tracking velocimetry. Our results indicate, first, that a combination of techniques is necessary to overcome their intrinsic limitation and, second, that the inherent asymmetry generated by isotropic gold nanoparticle deposition onto silica surfaces may enable particle motility. Full article

The behavior of oil droplets at solid surfaces is a key aspect of oil production and environmental protection. In this paper, the mechanisms of attachment and detachment of oil aggregates are studied via molecular dynamics simulations. The influence of oil–surface interactions on the shape and structure of adsorbed clusters is discussed. Using selected shape metrics, we prove quantitatively that the shape of oil aggregates changes from almost spherical droplets, through multilayer structures, to monolayer films. The oil detachment from solid surfaces plays a major role in enhanced oil recovery. Here, we investigated oil droplet detachment from the solid surface immersed in Janus nanoparticle suspensions. The nanoparticle is modeled as a dimer built of segments that exhibit different affinities to oil and solvent molecules. Our results indicated that the adsorption of Janus dimers on the surface of oil droplets played an essential role in the oil removal processes. Stronger adsorption causes faster detachment of the oil droplet. Based on our findings, suspensions of Janus dimers can be considered to be high-performance agents in removing oil droplets from solid surfaces. Full article