Search Results (2,464)

The growing demand for sustainable and efficient synthetic methodologies has brought nanocatalysis to the forefront of modern organic chemistry, particularly in the construction of heterocyclic compounds through multicomponent reactions (MCRs). Among various nanocatalysts, calcium oxide nanoparticles (CaO NPs) have gained significant attention because of their strong basicity, thermal stability, low toxicity, and cost-effectiveness. This review provides a comprehensive account of the recent strategies using CaO NPs as heterogeneous catalysts for the green synthesis of nitrogen- and oxygen-containing heterocycles through MCRs. Key reactions such as Biginelli, Hantzsch, and pyran annulations are discussed in detail, with emphasis on atom economy, reaction conditions, product yields, and catalyst reusability. In many instances, CaO NPs have enabled solvent-free or aqueous protocols with high efficiency and reduced reaction times, often under mild conditions. Mechanistic aspects are analyzed to highlight the catalytic role of surface basic sites in facilitating condensation and cyclization steps. The performance of CaO NPs is also compared with other oxide nanocatalysts, showcasing their benefits from green metrics evaluation like E-factor and turnover frequency. Despite significant progress, challenges remain in areas such as asymmetric catalysis, industrial scalability, and catalytic stability under continuous use. To address these gaps, future directions involving doped CaO nanomaterials, hybrid composites, and mechanochemical approaches are proposed. This review aims to provide a focused and critical perspective on CaO NP-catalyzed MCRs, offering insights that may guide further innovations in sustainable heterocyclic synthesis. Full article

As industrial waste gas, nitrogen dioxide (NO₂) is a serious hazard to air pollution and human health, and there is a pressing demand for developing high-performance NO₂ gas sensors. Tin disulfide (SnS₂), a representative two-dimensional metal sulfide characterized by a significant specific surface area, a suitable electron band gap, and an easily tunable layered structure, shows a broad application prospect in gas sensing applications. Nevertheless, SnS₂-based gas sensors suffer from poor sensitivity, which seriously hinders their application in room temperature gas sensing. In this study, Ag/SnS₂ heterojunction nanomaterials were synthesized by an in situ reduction approach. The findings reveals that the gas-sensitive response of the Ag/SnS₂ nanocomposites at room temperature under visible light irradiation can achieve 10.5 to 1 ppm NO₂, with a detection limit as low as 200 ppb, which realizes the room-temperature detection of Sub-ppm NO₂. Meanwhile, the sensor exhibits good selectivity, reproducibility (cyclic stability > 95%). The improved gas sensitivity of the Ag/SnS₂ sensor can be due to the synergistic effect of the carrier separation at the Ag/SnS₂ Schottky junction and the localized surface plasmon resonance (LSPR) of Ag nanoparticles. The LSPR effect significantly enhances light absorption and surface-active site density, facilitating trace NO₂ detection at room temperature. This study provides the foundation for the subsequent development of room temperature layered metal sulfide gas sensors. Full article

This study reports the development of a fiber-optic localized surface plasmon resonance (FO-LSPR) sensor incorporating a three-dimensional micropillar array functionalized with gold nanoparticles. The micropillar structures were fabricated on the fiber facet using a single-mask imprint lithography process, followed by nanoparticle immobilization to create a composite plasmonic surface. Compared with flat polymer-coated fibers, the micropillar array markedly increased the effective sensing surface and enhanced light trapping by providing anti-reflective conditions at the interface. Consequently, the sensor demonstrated superior performance in refractive index sensing, yielding a sensitivity of 4.54 with an R² of 0.984, in contrast to 3.13 and 0.979 obtained for the flat counterpart. To validate its biosensing applicability, Interleukin-8 (IL-8), a cancer-associated cytokine, was selected as a model analyte. Direct immunoassays revealed quantitative detection across a broad dynamic range (0.1–1000 pg/mL) with a limit of detection of 0.013 pg/mL, while specificity was confirmed against non-target proteins. The proposed FO-LSPR platform thus offers a cost-effective and reproducible route to overcome the surface-area limitations of conventional designs, providing enhanced sensitivity and stability. These results highlight the potential of the micropillar-based FO-LSPR sensor for practical deployment in point-of-care diagnostics and real-time biomolecular monitoring. Full article

In recent years, the use of silver nanoparticles (AgNPs) in various fields has been investigated due to their highly potent properties. One of these areas is the adaptation of AgNPs to food packaging/preservation technologies. The primary reasons for the use of AgNPs in food preservation studies are their high levels of antibacterial, antioxidant, and antifungal activities. In particular, the slow and controlled release of silver provides a sustained protective effect throughout the contact period of AgNP-integrated packaging with food and reduces microbial load by preventing biofilm formation. Furthermore, high thermal stability of AgNPs provides high protection to foods under various conditions. Their high surface-area-to-volume ratio, making them effective even at low concentrations, further supports AgNPs as a promising alternative in food preservation technologies. Moreover, their ease of surface modification facilitates the integration of these nanoparticles (NPs) into polymer matrices, biodegradable films, and coatings. Additionally, some AgNP-based films are also used in smart packaging applications, providing a color change indicator of degradation. Their broad pH tolerance enhances their applicability to a variety of food types, from dairy to meat products. For all these reasons, AgNPs are considered as one of the essential components of innovative food packaging to slow down food spoilage, prevent microbial contamination, and provide safer, longer-lasting products to the consumer, and studies on them are ongoing. Full article

Nickel oxide (NiO), a wide bandgap p-type semiconductor, has emerged as a promising material for electrochemical sensing owing to its excellent redox properties, chemical stability, and facile synthesis. Its strong electrocatalytic activity enables effective detection of diverse analytes, including glucose, hydrogen peroxide, environmental pollutants, and biomolecules. Advances in nanotechnology have enabled the development of NiO-based nanostructures such as nanoparticles, nanowires, and nanoflakes, which offer enhanced surface area and improved electron transfer. Integration with conductive materials like graphene, carbon nanotubes, and metal–organic frameworks (MOFs) further enhance sensor performance through synergistic effects. Innovations in synthesis techniques, including hydrothermal, sol–gel, and green approaches, have expanded the applicability of NiO in next-generation sensing platforms. This review summarizes recent progress in the structural engineering, composite formation, and electrochemical mechanisms of NiO-based materials for advanced electrochemical sensing applications. Full article

Today, hydrogen is already widely regarded as up-and-coming source of energy. It is essential to meet energy needs while reducing environmental pollution, since it has a high energy capacity and does not emit carbon oxide when burned. However, for the widespread application of hydrogen energy, it is necessary to search new technical solutions for both its production and storage. A promising effective and cost-efficient method of hydrogen generation and storage can be the use of solid materials, including nanomaterials in which chemical or physical adsorption of hydrogen occurs. Focusing on the recommendations of the DOE, the search is underway for materials with high gravimetric capacity more than 6.5% wt% and in which sorption and release of hydrogen occurs at temperatures from −20 to +100 °C and normal pressure. This review aims to summarize research on hydrogen generation and storage using silicon nanostructures and silicon composites. Hydrogen generation has been observed in Si nanoparticles, porous Si, and Si nanowires. Regardless of their size and surface chemistry, the silicon nanocrystals interact with water/alcohol solutions, resulting in their complete oxidation, the hydrolysis of water, and the generation of hydrogen. In addition, porous Si nanostructures exhibit a large internal specific surface area covered by SiH_x bonds. A key advantage of porous Si nanostructures is their ability to release molecular hydrogen through the thermal decomposition of SiHx groups or in interaction with water/alkali. The review also covers simulations and theoretical modeling of H₂ generation and storage in silicon nanostructures. Using hydrogen with fuel cells could replace Li-ion batteries in drones and mobile gadgets as more efficient. Finally, some recent applications, including the potential use of Si-based agents as hydrogen sources to address issues associated with new approaches for antioxidative therapy. Hydrogen acts as a powerful antioxidant, specifically targeting harmful ROS such as hydroxyl radicals. Antioxidant therapy using hydrogen (often termed hydrogen medicine) has shown promise in alleviating the pathology of various diseases, including brain ischemia–reperfusion injury, Parkinson’s disease, and hepatitis. Full article

Octominin is a peptide derived from the Octopus minor defense protein, which has shown antimicrobial and immunomodulatory properties. The present study describes the efficacy of Octominin-encapsulated chitosan (CN) nanoparticles (Octominin-CNPs) on in vitro and dermal wound healing in zebrafish. Initial viability analysis revealed there was no significant toxicity of Octominin-CNPs up to 200 μg/mL in human dermal fibroblast (HDF) cells and in zebrafish larvae (up to 50 μg/mL). Moreover, the potential wound healing activity of Octominin-CNPs was observed using the cell-scratch assay. In the in vivo study, wounded adult zebrafish were applied with the appropriate treatment (PBS, CNPs, Octominin, and Octominin-CNPs) 20 μg/wound/fish as a topical application at 0, 2, and 4 days post-wounding (dpw) while photographs of each wound site were taken at 2, 4, 7, 10, 14, and 21 dpw, and surface area was measured using ImageJ software (Ver. 1.8.0, NIH, Bethesda, MD, USA) to calculate the wound healing percentage (WHP) and wound healing rate (WHR). From the observed results, at 4 dpw, all treatments showed a negative impact on wound healing, where the lowest WHR and the WHP were given by the negative control (NC) until the 14th day. After 7 dpw, all fish except the NC showed increased wound healing activity. Compared to the Octominin, the Octominin-CNPs showed higher activity, which was at its peak on 21 dpw. Furthermore, Octominin-CNPs suppressed the expression of pro-inflammatory cytokine and chemokine mRNA expression with increased wound healing efficacy, and tissue repair compared to the Octominin-alone-treated fish at 7 dpw. Together, the observed results give insights into the use of nanoencapsulation as a means of drug delivery, especially for small peptides. Full article

Microplastics (MPs), as an emerging persistent contaminant, pose a potential threat to ecosystems and human health. The adsorptive removal of MPs from aqueous environments using magnetic nanoparticles has become a particularly promising remediation technology. Nevertheless, there remain significant knowledge gaps regarding its adsorption mechanism, especially how the key physical properties of magnetic nanoparticles regulate their adsorption behavior towards MPs. This study first investigated the relationship between the particle size of Fe₃O₄ nanoparticles and their adsorption efficacy for MPs. The results demonstrated a non-monotonic, size-dependent adsorption of MPs by Fe₃O₄ nanoparticles, with the adsorption efficiency and capacity following the order: 300 nm > 15 nm > 100 nm. This non-linear relationship suggested that factors other than specific surface area (which would favor smaller particles) are significantly influencing the adsorption process. Isotherm analysis indicated that the adsorption is not an ideal monolayer coverage process. Kinetic studies showed that the adsorption process could be better described by the pseudo-second-order model, while intra-particle diffusion played a critical role throughout the adsorption process. Furthermore, the effect of pH on adsorption efficiency was examined, revealing that the optimal performance occurs under neutral to weak acidic conditions, which is consistent with measurements of surface charges of nanoparticles. These findings suggest that the adsorption is not determined by specific surface area but is dominated by electrostatic interactions. The size-dependent adsorption of MPs by Fe₃O₄ nanoparticles provides new insights for the modification of magnetic adsorbents and offers a novel perspective for the sustainable and efficient remediation of environmental MPs pollution. Full article

The rapid development of nanotechnology has significantly transformed the design and performance of glucose biosensors, leading to enhanced sensitivity, selectivity, and real-time monitoring capabilities. This review highlights recent advances in glucose-sensing platforms facilitated by nanomaterials, including metal and metal oxide nanoparticles, carbon-based nanostructures, two-dimensional materials, and metal–organic frameworks (MOFs). The integration of these nanoscale materials into electrochemical, optical, and wearable biosensors has addressed longstanding challenges associated with enzyme stability, detection limits, and invasiveness. Special emphasis is placed on non-enzymatic glucose sensors, flexible and wearable devices, and hybrid nanocomposite systems. The multifunctional properties of nanomaterials, such as large surface area, excellent conductivity, and biocompatibility, have enabled the development of next-generation sensors for clinical, point-of-care, and personal healthcare applications. The review also discusses emerging trends such as biodegradable nanosensors, AI-integrated platforms, and smart textiles, which are poised to drive the future of glucose monitoring toward more sustainable and personalized healthcare solutions. Full article

Glycosaminoglycans (GAGs) are part of the extracellular matrix (ECM) and play a major role in maintaining their physiological function. During pathological processes, the ECM is remodeled and its GAG composition changes. Hyaluronic acid (HA) is one of the GAGs that plays an important role in pathological processes such as inflammation and cancer and is therefore an interesting target for imaging. To provide iron oxide nanoparticles (IONP) that bind to hyaluronic acid (HA) as specific probes for molecular imaging, a peptide with high affinity for HA was covalently bound to the surface of commercial IONP (synomag^®-D, NH2) leading to hyaluronic acid-specific iron oxide nanoparticles (HAIONPs). Affinity measurements using a quartz crystal microbalance (QCM) showed a very high affinity of HAIONP to HA, but not to the control chondroitin sulfate (CS). HAIONPs exhibit a very high magnetic particle spectroscopy (MPS) signal amplitude, which predestines them as HA-selective tracers for magnetic particle imaging (MPI). The high relaxivity coefficient r₂ also makes HAIONP suitable for magnetic resonance imaging (MRI) applications. HAIONP therefore offers excellent prerequisites for further development as a probe for the specific quantitative imaging of the HA content of the ECM in pathological areas. Full article

This study investigated the correlation between the dispersion stability and photocatalytic efficiency of titanium dioxide (TiO₂) nanoparticles for the development of self-cleaning functional concrete. After pretreatment of P25 TiO₂ with aqueous solutions of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene glycol methyl ether (PEGME), dynamic light scattering (DLS) and zeta potential measurements were performed, and as a result, a 0.1 wt% PVA solution was optimal for inhibiting aggregation, with an average hydrodynamic diameter of 1.4 µm and a zeta potential of −11 mV. In methylene blue photolysis, the reaction rate constant (k_app) was 1.71 × 10⁻² min⁻¹ (R² = 0.98), which was improved by 11.4 times compared to the control group, and was about twice as high in the concrete specimen experiment. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses confirmed an anatase-to-rutile ratio of 81:19 particle sizes of 10–30 nm, and a specific surface area of 58.985 m²·g⁻¹. As a result, it is suggested that PVA pretreatment is a practical method to effectively improve the photocatalytic performance of TiO₂-based self-cleaning concrete. Full article

Developing highly permeable and selective membranes for energy-efficient CO₂/CH₄ separation remains challenging. Mixed-matrix membranes (MMMs) integrating polymer matrices with metal–organic frameworks (MOFs) offer significant potential. However, rational filler–matrix matching presents substantial difficulties, constraining separation performance. In this work, defects were engineered within fluorinated MOF ZU-61 through the partial replacement of 4,4′-bipyridine linkers with pyridine modulators, producing high-porosity HP-ZU-61 nanoparticles exhibiting a 267% BET surface area enhancement (992.9 m² g⁻¹) over low-porosity ZU-61 (LP-ZU-61) (372.2 m² g⁻¹). The HP-ZU-61/6FDA-DAM MMMs (30 wt.%) demonstrated homogeneous filler dispersion and pre-served crystallinity, achieving a CO₂ permeability of 1626 barrer and CO₂/CH₄ selectivity (33), surpassing the 2008 Robeson upper bound. Solution-diffusion modeling indicated ligand deficiencies generated accelerated diffusion pathways, while defect-induced unsaturated metal sites functioned as strong CO₂ adsorption centers that maintained solubility selectivity. This study establishes defect engineering in fluorinated MOF-based MMMs as a practical strategy to concurrently overcome the permeability–selectivity trade-off for efficient CO₂ capture. Full article

Nanoplastics have emerged as significant global pollutants, drawing worldwide concern. Due to their small particle size, large specific surface area, and high surface activity, nanoplastics can combine with other environmental contaminants, including environmental nanoparticles, persistent organic pollutants, antibiotics, and endocrine-disrupting chemicals. This review summarizes recent progress on the environmental behavior of nanoplastics and their complex effects on food safety when co-exposed to various contaminants. These composite pollutants accumulate in foods and the environment, and are ultimately taken up by humans, posing potential toxic effects on human health. In the future, the interaction mechanisms between environmental NPs and various co-contaminants, as well as their transfer routes from food to humans, should be addressed. Full article

Among the many nanomaterials studied for biomedical uses, silica and gold nanoparticles have gained significant attention because of their unique physical and chemical properties and their compatibility with living tissues. Mesoporous silica nanoparticles (MSNs) have great stability and a large surface area, while gold nanoparticles (AuNPs) display remarkable optical features. Both types of nanoparticles have been widely researched for their individual roles in drug delivery, imaging, biosensing, and therapy. When combined with gadolinium (Gd), a common contrast agent, these nanostructures provide improved imaging due to gadolinium’s strong paramagnetic properties. This study focuses on incorporating gold nanoparticles and gadolinium into a silica matrix to develop a theranostic system. Various analytical techniques were used to characterize the nanocomposites, including infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), nitrogen adsorption, scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray fluorescence (XRF), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and neutron activation analysis (NAA). Techniques like XRF mapping, XANES, nitrogen adsorption, SEM, and VSM were crucial in confirming the presence of gadolinium and gold within the silica network. VSM and EPR analyses confirmed the attenuation of the saturation magnetization for all nanocomposites. This validates their potential for biomedical applications in diagnostics. Moreover, activating gold nanoparticles in a nuclear reactor generated a promising radioisotope for cancer treatment. These results indicate the potential of using a theranostic nanoplatform that employs mesoporous silica as a carrier, gold nanoparticles for radioisotopes, and gadolinium for imaging purposes. Full article

Thermochemical energy storage (TCES) has gained significant attention as a high-capacity, long-duration solution for renewable energy integration, yet material-level challenges hinder its widespread adoption. This review for the first time systematically examines recent advancements in nano-engineered composite thermochemical materials (TCMs), focusing on their ability to overcome intrinsic limitations of conventional systems. Sorption-based TCMs, especially salt hydrates, benefit from nano-engineering through carbon-based additives like CNTs and graphene, which enhance thermal conductivity and reaction kinetics while achieving volumetric energy densities exceeding 200 kWh/m³. For reversible reaction-based systems operating at higher temperatures (250–1000 °C), the strategies include (1) nanoparticle doping (e.g., SiO₂, Al₂O₃, carbonaceous materials) for the mitigation of sintering and agglomeration; (2) flow-improving agents to enhance fluidization; and (3) nanosized structure engineering for an enlarged specific surface area. All these approaches show promising results to address the critical issues of sintering and agglomeration, slow kinetics, and poor cyclic stability for reversible reaction-based TCMs. While laboratory results are promising, challenges still persist in side reactions, scalability, cost reduction, and system integration. In general, while nano-engineered thermochemical materials (TCMs) demonstrate transformative potential for performance enhancement, significant research and development efforts remain imperative to bridge the gap between laboratory-scale achievements and industrial implementation. Full article