Search Results (839)

Carbon nanotubes (CNTs) have become one of the most widely investigated nanomaterials for gas sensing because their nearly one-dimensional geometry, large surface-to-volume ratio, hollow structure, and tunable metallic or semiconducting character allow trace adsorption events to be transduced into measurable electrical signals at or near room temperature. This review summarizes CNT-based gas sensors from a system-oriented perspective, linking four interconnected topics: (i) CNT structure, synthesis, and film/device fabrication; (ii) sensing mechanisms, including charge transfer, Schottky-barrier modulation, carrier-lifetime effects, and field-enhanced ionization; (iii) functional interfaces based on noble metals, metal oxides, conducting polymers, and graphene derivatives; and (iv) gas-specific and flexible/wearable device performance. Particular attention is given to recent room-temperature and mechanically compliant CNT-film sensors fabricated on polymer, cellulose, paper, textile, and mask substrates. Rather than cataloguing only individual response values, this review compares representative devices in terms of target gas, operating condition, sensitivity, recovery strategy, selectivity, humidity tolerance, and wearable relevance. The review concludes by discussing remaining challenges in reproducibility, selectivity, humidity compensation, recovery, power consumption, and standardization, and by outlining future directions toward robust, scalable, and intelligent CNT-enabled sensing systems. Full article

Cyanobacteria are essential primary producers in aquatic ecosystems. Silver nanoclusters (Ag NCs) are emerging ultrasmall nanomaterials with broad applications; however, they inevitably enter aquatic environments. This study investigated the nanotoxicity of Ag NCs on model cyanobacterium Synechococcus elongatus PCC 7942 (Syn7942), revealing concentration-dependent growth inhibition with a 72 h half-maximal effective concentration of 1.19 mg L⁻¹. Ag NCs internalized into Syn7942 cells severely impaired the photosynthetic machinery, evidenced by reduced chlorophyll a content and suppressed photochemical reactions, leading to impaired electron transport. This photosynthetic dysfunction resulted in substantial reactive oxygen species generation and lipid peroxidation, as indicated by elevated levels of malondialdehydes. Although the activities of key antioxidant enzymes were enhanced, oxidative damage ultimately overwhelmed the cellular defense capacity. Furthermore, quantitative analysis of silver ions (Ag⁺) release coupled with comparative toxicity assays of Ag⁺ and Ag NCs confirmed that the toxicity originates from the Ag NCs themselves, rather than from the released Ag⁺. Transcriptional level analysis revealed that Ag NCs altered the expression of genes involved in photosynthesis and metal detoxification. Collectively, this study reveals a unique toxicity mechanism for Ag NCs distinct from that for Ag NPs and Ag⁺, highlighting the potential ecological risks posed by ultrasmall nanomaterials. Full article

MXenes have emerged as a rapidly expanding family of two-dimensional transition-metal carbides, nitrides, and carbonitrides, characterized by exceptional compositional diversity, tunable surface chemistry, metallic conductivity, hydrophilicity, mechanical flexibility, and rich redox activity. These characteristics make MXenes highly attractive for next-generation technologies, including energy storage and conversion, catalysis, electromagnetic interference shielding, sensors, water purification, biomedical systems, and smart functional devices. However, the performance of MXene-based materials is strongly governed by their synthesis routes, defect structures, interlayer spacing, surface terminations, oxidation stability, and interfacial interactions with polymers, metals, oxides, and other two-dimensional materials. Therefore, a structure–property-oriented understanding is essential for moving MXene research from empirical material development toward rational functional design. Unlike application-centered summaries, this review develops a cross-application engineering framework that connects MXene synthesis and processing with multiscale structure, functional properties, performance trade-offs, and translational requirements. First, major synthesis and processing strategies are discussed, including selective etching, delamination, intercalation, surface modification, and scalable fabrication. Next, the relationships between MXene composition, morphology, surface chemistry, electrical conductivity, electrochemical behavior, mechanical properties, and environmental stability are analyzed. Recent advances in functionalization, heterostructure construction, and composite engineering are then highlighted to illustrate how MXene properties can be tailored for emerging applications. Finally, key challenges related to oxidation, restacking, long-term stability, environmental safety, reproducibility, and industrial translation are critically evaluated. This review aims to establish a design framework for engineering MXene nanomaterials toward high-performance, stable, and scalable emerging technologies. Full article

Metal oxide nanoparticles have been the subject of intense research interest because of their remarkable physicochemical properties, such as their high surface area, particle size tunability, outstanding chemical stability, optical activity, catalytic efficiency, and antimicrobial behavior. These properties make them very useful in environmental, biomedical, energy, sensing, agricultural and industrial applications. The chosen synthesis method is important in controlling the morphology, crystallinity, surface charge, band gap and overall performance of metal oxide nanoparticles. They have been prepared using various physical, chemical and biological means, such as sol–gel, co-precipitation, hydro/solvothermal, microwave-assisted, sonochemical, combustion and green synthesis. Of these, green synthesis is gaining more interest as it employs plant extracts, microorganisms, and other biological materials as reducing agents, stabilizing and capping agents that make the process more eco-friendly and cost-effective. Recent advancements in the synthesis and application of metal oxide nanoparticles are discussed. There is an emphasis on the major synthesis routes, the main factors that influence the formation of nanoparticles, the characterization techniques used, and the structure–property relationships uncovered. A special focus is given to the influence of synthesis parameters, such as the type of precursor and the pH, temperature, reaction time, solvents and capping agents, on the properties of nanoparticles. In addition, the uses of metal oxide nanoparticles in photocatalysis, wastewater treatment, antimicrobial activity, drug delivery, biosensing, energy storage, gas sensing, and agriculture are also included. Finally, present challenges, toxicity issues, the problems of large-scale production, and future research directions are discussed to support the practical and sustainable uses of metal oxide nanoparticles. Full article

Food safety systems are increasingly challenged by globalized supply chains, emerging contaminants, and the need for rapid decision-making before contaminated products reach consumers. Although conventional methods remain essential for confirmatory analysis, their dependence on centralized facilities, specialized personnel, and time-intensive workflows limits their suitability for real-time monitoring. Sustainable nanotechnology offers a promising approach to address these limitations by enabling rapid, sensitive, portable, and resource-efficient contaminant detection. This review critically examines recent advances in nano-enabled platforms for detecting foodborne pathogens, toxins, pesticide residues, heavy metals, allergens, and other food-related contaminants. Emphasis is placed on colorimetric, fluorescent, electrochemical, surface-enhanced Raman scattering, and biosensor-based systems employing sustainable nanomaterials, including biopolymer nanoparticles, carbon-based nanostructures, metal and metal oxide nanoparticles, quantum dots, and hybrid nanocomposites. The roles of green synthesis, low-toxicity materials, reduced solvent use, and safe-by-design strategies are evaluated in relation to environmental sustainability and practical implementation. The integration of nanosensors with smart packaging, portable devices, Internet of Things platforms, artificial intelligence, and data-driven risk assessment is also discussed. Key challenges include matrix interference, reproducibility, sensor stability, scalability, regulatory approval, environmental fate, and consumer acceptance. Continued progress will require validated, scalable, and environmentally responsible technologies capable of reliable operation under real-world food system conditions. Full article

Exhaled breath analysis has emerged as a promising non-invasive approach for disease diagnosis, leveraging gas sensors for their high sensitivity, portability, and real-time monitoring capabilities. Two-dimensional nanomaterials, such as graphene, transition metal dichalcogenides (TMDs), MXenes, black phosphorus, and metal–organic frameworks (MOFs), exhibit exceptional gas-sensing properties due to their atomic-scale thickness, ultra-large specific surface area, and tunable electronic structures. These characteristics enable enhanced gas adsorption and room-temperature operation, making them ideal for detecting ppb-level biomarkers like acetone, ammonia, and nitric oxide in breath. However, sensors based on pristine 2D materials face challenges including slow response/recovery kinetics, poor stability, weak humidity resistance, and limited selectivity in complex breath environments. To address these limitations, functionalization strategies have been developed to engineer material properties. Key approaches include heteroatom doping to modulate electronic band structures, heterojunction construction to facilitate charge transfer and improve selectivity, and noble metal decoration for catalytic enhancement of gas adsorption. Additionally, light irradiation has been employed to regulate the carrier concentration on the surface of sensitive materials. These strategies significantly boost sensor performance, achieving ppb-level detection limits, robust humidity resistance, and rapid response. Future directions involve integrating functionalized 2D materials into wearable, multiplexed sensor arrays for simultaneous biomarker detection, coupled with machine learning for real-time diagnostic platforms. Full article

Heavy metal pollution has become a critical concern in agricultural ecosystems driven by a complex matrix of industrial practices, high-input fertilizers, metal-based agrochemicals, and wastewater irrigation. While the previous literature typically highlights general physiological symptoms of heavy metal stress, this review provides a novel, comprehensive framework that bridges three independent pillars: specific industrial applications dictating elemental pathway, localizes active root-zone transport kinetics, and an engineering-based evaluation of emerging remediation strategies. We systematically synthesized literature from 2000 to 2026 across major databases (WoS, PubMed and Google Scholar), applying strict inclusion criteria based on data validation, experimental reproducibility, and mechanistic depth. We examine the geochemical behavior, cellular toxicity, and plant resilience mechanics of seven priority elements like cadmium, lead, arsenic, aluminum, mercury, chromium and molybdenum. Rather than merely reiterating superficial visual damage like chlorosis or stunted growth, we focus on physiological and molecular root causes of phytotoxicity, including the structural hijacking of essential nutrient networks, intracellular reduction cascades and organelle-specific oxidative disruption. This review also discussed the discovery of specialized, energy-dependent eukaryotic transport mechanisms like ABC transporters and a comparative operational blueprint evaluating physical–chemical conventional remediation techniques against advanced in situ and ex situ biotechnological approaches, including biochar assistance, microbial engineering, rhizosphere synergies, and engineered nanomaterials. By systematically linking industrial source dynamics with cellular toxicological mechanisms and field-scale engineering feasibility, this review establishes an actionable roadmap for future genetic, agronomic, and management interventions aimed at securing global food. Full article

Hybrid nanofluids with enhanced thermal conductivity have emerged as promising candidates for efficient heat removal in advanced energy systems and next-generation thermal management technologies. In particular, the use of viscoelastic base fluids embedded with radiatively active nanoparticles enables improved thermal regulation in solar collectors, electronic cooling units, and high-temperature industrial processes. This study presents a comparative thermal investigation of mono- and hybrid nanofluids comprising the ferro-oxide (Fe₃O₄) and copper (Cu) metallic particles dispersed in ethylene glycol (C₂H₆O₂), under magnetohydrodynamic (MHD) viscoelastic flow over a stretched surface. Accurate modeling of heat and mass phenomena in such fluids arises from their growing application in advanced thermal systems, including cooling technologies, electronic devices, and renewable energy modules. Unlike conventional models, the current analysis incorporates the Cattaneo–Christov heat flux framework to capture non-Fourier thermal relaxation effects, alongside the influence of thermal radiation and solutal transport. The developed system is truncated into dimensionless form with the proper choice of appropriate quantities, whose solution methodology is based on the implementation of a Runge–Kutta scheme. Compiled observations suggest that the hybrid nanomaterial exhibits more pronounced thermal recovery, while mono nanofluid attributes lower impact. Moreover, increasing the viscoelastic and magnetic parameters leads to notable variations in temperature and concentration distributions. This work advances the current literature by simultaneously integrating viscoelastic rheology, dual nanoparticle suspensions, and non-classical heat conduction laws, providing new insights for optimizing thermal performance in engineering applications. Full article

Nanostructured Co₃O₄ was synthesized via a sol–gel approach employing the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) and subsequently evaluated as a high-performance anode material for lithium-ion batteries. Ionic liquids, distinguished by their low volatility, high thermal stability, and tunable chemical properties, represent a greener alternative to conventional organic solvents for the synthesis of functional nanomaterials. The electrochemical performance of the as-prepared material was systematically assessed through galvanostatic charge–discharge cycling, cyclic voltammetry, and rate capability tests. The Co₃O₄ electrode exhibited a high reversible capacity of approximately 1100 mAh g⁻¹ after 50 cycles at a current density of 200 mA g⁻¹, along with excellent coulombic efficiency approaching ~100% after the initial cycles. Furthermore, the material demonstrated strong rate capability, delivering about 600 mAh g⁻¹ at 1 C, and recovering its capacity upon returning to lower current densities. The improved electrochemical performance is primarily attributed to the nanoscale architecture induced by the ionic liquid-assisted synthesis, which facilitates rapid lithium-ion transport and effectively buffers volume variations during repeated cycling. Notably, the ionic liquid serves a dual function as both a green reaction medium and a structure-directing agent, enabling precise control over the material’s morphology and properties. This study demonstrates a versatile strategy for the rational design of potential transition-metal oxide anodes, paving the way for high-performance electrode materials. The findings contribute to the development of next-generation lithium-ion batteries tailored for clean and sustainable energy storage applications. Full article

The release of microplastic fibers from synthetic textiles during domestic laundering is a major contributor to aquatic pollution. Nanomaterial-based surface treatments have recently emerged as a potential route for minimizing microfiber shedding. This study investigates the use, for the first time, of metal oxide nanoparticles (TiO₂, ZnO, MgO) functionalized with fatty acids (oleic acid (OA) and stearic acid (SA)) as microfiber-retaining agents. The nanoparticles were modified via a simple adsorption process at room temperature, monitored by zeta potential analysis, and confirmed by DSC-TG and FTIR-ATR analysis. When applied to polyester fabrics during simulated washing cycles, the hydrophobicity of the polyester surface coated with functionalized nanoparticles was assessed via contact angle measurements, and the effect on microfiber shedding was evaluated by the filtration of wastewater and by weighing the mass of fibers retained in the filters. ZnO and MgO nanoparticles treated with stearic and oleic acid demonstrated a significant reduction in fiber shedding compared to commercial laundry detergent (approximately 46–70%). In contrast, fatty acid adsorption onto TiO₂ was less efficient (reduction in microfiber release ~23%), and the TiO₂-based systems showed limited improvement in microfiber shedding, possibly due to insufficient hydrophobic interaction. These results demonstrate that fatty acid functionalization of low-cost inorganic nanoparticles is a promising strategy for mitigating microfiber pollution in laundry effluents. Full article

Repairing large bone defects remains a clinical challenge in orthopedics. Near-infrared (NIR) photothermal therapy (PTT) has recently expanded from high-temperature tumor ablation to the field of mild bone regeneration. Maintaining temperatures within a mild window of 40–42 °C accelerates bone healing by activating osteogenic signals, modulating the immune microenvironment, and providing antibacterial effects. It is important to note that the therapeutic efficacy is highly dependent on the precise control of both temperature and exposure duration: temperatures exceeding 42–43 °C can induce cell apoptosis, while temperatures above 45 °C typically cause necrosis. The reviewed studies employed controlled exposure times (typically 5–15 min per session) to maintain cell viability above 85%, with functional assessments confirming preserved osteogenic differentiation capacity of bone marrow-derived mesenchymal stem cells (BMSCs) and maintained macrophage plasticity after mild photothermal treatment. This performance depends on photothermal conversion materials. This paper reviews the applications of MXene, black phosphorus (BP), polydopamine/graphene oxide (PDA/GO), and metal-based nanomaterials in bone repair. We also analyze photothermal-based immune regulation, sequential repair strategies, and tumor theranostics. Finally, we discuss current challenges and future trends to guide the design of next-generation smart bone repair materials. Full article

Introduction: Heavy metal contamination in water represents a major environmental and public health challenge because toxic ions frequently occur as complex multi-species mixtures rather than isolated pollutants. This study presents a numerical design and optimization of a surface plasmon resonance (SPR) sensor based on a LaF/Au/BaTiO₃/WS₂ heterostructure for monitoring refractive-index changes associated with mixed heavy metal ions in aqueous media. Methodology: The optical response of the multilayer sensor was evaluated using the transfer matrix method under TM-polarized illumination at 633 nm. Systematic optimization was performed for the prism substrate, Au thickness, dielectric oxide layer, and 2D nanomaterial interface. The final configuration consisted of a LaF prism, 50 nm Au film, 2.0 nm BaTiO₃ spacer, and 0.80 nm WS₂ monolayer. Sensor performance was assessed using resonance-angle shift, sensitivity, detection accuracy, quality factor, figure of merit, FWHM, attenuation, and estimated limit of detection. Results and Discussion: The optimized LaF/Au/BaTiO₃/WS₂ configuration produced stable simulated SPR responses across single, binary, quaternary, and five-ion heavy metal matrices. The WS₂ monolayer provided the highest angular displacement among the evaluated 2D materials, while BaTiO₃ improved field confinement and limited optical damping in the numerical model. The configuration maintained attenuation near 1.6%, FWHM values around 7.9°, detection accuracy between 0.030 and 0.032 deg⁻¹, and model-based refractometric LoD values down to 3.49 × 10⁻⁵ RIU under the assumed angular-resolution criterion. Conclusions: The proposed LaF/Au/BaTiO₃/WS₂ SPR configuration provides a numerical framework for label-free monitoring of refractive-index changes associated with complex heavy-metal-ion mixtures in contaminated water. Experimental fabrication and testing are required to validate the simulated performance. Full article

Porous coordination polymers, alternatively known as metal–organic framework (MOF) nanoparticles, have acquired increasing significance in nanomaterials science, especially with the increased importance and versatility in catalysis. The complex structures of MOFs allow the incorporation of metal nodes, enclosing substrates, and functional linkers, thus enabling synergistic structural and functional engineering to produce capable catalytic active sites that provide solutions to decrease human activities in designing new organic reactions. Recently, Cu-MOF-mediated organic reactions hold a significant promise to substitute homogenous and heterogeneous catalysts due to their promising structural features such as tailorable porous structures, high-density catalytic active sites and surface area, sufficient framework stability, minimal leaching, and facile recovery and recyclability. This review emphasizes the significance of Cu-MOFs in synthetic chemistry, in particular, in the synthesis of organic compounds. It examines their applicability in hydrogenation, oxidation, cross-coupling/condensation reactions, functionalization at terminal alkenes and alkynes, intramolecular C-H amination, and other multicomponent reactions. In addition to these organic transformations, recent progress in Cu-MOF-catalyzed CO₂ electroreduction and nitrate reduction is also briefly described. Subsequently, the state-of-the-art synthetic methods of certain decorated Cu-MOFs are thoroughly elaborated as well as the essential structural parameters that govern the stability and recyclability of MOFs in organic transformations. This focused examination of Cu-MOFs is expected to provide useful information for future research endeavors in the field of MOF catalytic applications. Full article

The development of highly crystalline tungsten oxide nanomaterials remains challenging for catalytic applications due to the difficulty in achieving high phase purity without sacrificing metal oxide loading. This work addresses this limitation through an innovative fast hydrothermal synthesis at 100 °C for 4 h without autoclaves or surfactants, using citric acid as a critical structural directing agent. Such methodology reduces the synthesis time by 50–80% compared to existing hydrothermal routes. Citric acid was identified as the critical parameter controlling the nanosheet thickness (20 nm to 35 nm) and diameter (109 nm to 173 nm), acting as a coordinating ligand. The resulting nanosheets were used to prepare Pt/WO₃/Al₂O₃ catalysts with well-defined crystalline monoclinic WO₃ structures at 9.5% wt. loading. Normally, this phase is inaccessible by standard impregnation at equivalent loading. NH₃-TPD characterization confirmed that crystalline WO₃ generates strong acid sites absent in the reference wet impregnation catalyst. Glycerol hydrogenolysis tests revealed that the presence of monoclinic WO₃ reduces the average glycerol conversion rate by a factor of 3.8 and systematically shifts selectivity toward over-hydrogenolysis products (1-propanol and 2-propanol), despite identical WO₃ loading and surface densities below the literature optimum of 2.2 W atoms ${\mathrm{nm}}^{-2}$. These results demonstrate that the WO₃ crystalline phase is a primary determinant of catalytic performance, without taking into account increased loading. Such demonstration will be useful for the rational design of selective glycerol hydrogenolysis catalysts. Full article

The overreliance on chemical pesticides has caused severe environmental contamination, health risks, and increasing pest and pathogen resistance, creating an urgent need for greener and more efficient alternatives in sustainable agriculture. Microalgae-mediated green nano-synthesis has emerged as a promising strategy because of its environmental compatibility, cost-effectiveness, and multifunctional potential. This review critically summarizes recent advances in microalgae-derived nanomaterials for agricultural applications. First, we discuss the biochemical basis of nanoparticle biosynthesis, highlighting the roles of microalgal polysaccharides, proteins, photosynthetic pigments, extracellular polymeric substances, and secondary metabolites as reducing, capping, and stabilizing agents. We then summarize intracellular and extracellular synthesis pathways, advanced synthesis strategies, and key reaction parameters, including temperature, pH, and metal precursor concentration, which regulate nanoparticle size, morphology, stability, and yield. Subsequently, major microalgae-derived nanomaterials, including gold, silver, selenium, zinc oxide, bimetallic, and other functional nanoparticles, are discussed in relation to their agricultural applications. These nanomaterials show potential in bacterial, fungal, and viral disease control, biofilm disruption, plant growth promotion, yield enhancement, and abiotic stress mitigation. Their agronomic effects are associated with multiple mechanisms, including reactive oxygen species generation, pathogen membrane disruption, inhibition of biofilm formation, enhanced nutrient bioavailability, antioxidant regulation, and activation of plant systemic resistance. In addition, this review evaluates the phytotoxicity, biocompatibility, soil microbial impacts, and environmental safety of microalgae-derived nanomaterials, emphasizing that green synthesis does not automatically guarantee biosafety. Finally, we discuss their integration into circular agriculture through CO₂ capture and wastewater-derived metal recovery, while highlighting remaining challenges in scale-up, quality control, economic feasibility, regulatory classification, and public acceptance. Overall, microalgae-mediated nanotechnology offers a promising platform for developing safer, more efficient, and circular agricultural inputs. Full article