Search Results (1,380)

In various areas of human activity, there is a need for new antimicrobial agents that are minimally hazardous to humans and the environment while remaining effective against multidrug-resistant microorganisms. The use of nanomaterials, particularly carbon-based ones, for this purpose is attracting growing interest. This review presents a quantitative analysis, based on published data, of the antibacterial and antifungal activity of various carbon nanomaterials, focusing on fullerenes, nanodiamonds, graphene oxide, carbon nanotubes, and carbon dots. Their antimicrobial activity is compared both among themselves and with other antimicrobial agents; the effects of their physicochemical properties, functionalization, and photodynamic activity on this activity are also examined. Full article

This study presents a hierarchical conductive-network strategy to overcome the performance trade-off in cement structural supercapacitors (CSSCs). By incorporating one-dimensional carbon nanotubes (CNTs) and two-dimensional graphene oxide (GO) into Portland cement, we simultaneously enhance its electrochemical and mechanical properties. The approach exploits the complementary roles of the two nanomaterials: CNTs establish a three-dimensional percolation network that facilitates electron transport, while GO promotes formation of a denser calcium silicate hydrate (C-S-H) gel and refines the pore structure by complexing with calcium ions, thereby improving ionic pathways. The k12gc sample attains a specific capacitance of 66.8 F g⁻¹ at 0.1 mA cm⁻², a 58.4% rise in conductivity and a 63% reduction in charge-transfer resistance. At the same time, the composite reduces harmful macropores by 27.9% and strengthens the material, with compressive and flexural strengths increasing by 4.8% and 8.3%, respectively. This work establishes a rational design principle based on functional division between CNTs and GO for developing high-performance, multifunctional CSSCs. Full article

Laser-induced graphene (LIG) enables rapid conversion of polymer substrates into conductive carbon materials. In this study, nitrogen-containing carbon nanomaterials were fabricated on polyetherimide (PEI) substrates using empirical screening of two specific process points. The resulting materials were characterized using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy to correlate structural features with electron-transfer behavior. Raman and XPS analyses showed different structure and morphology depending on irradiation regime. The carbon materials with a higher sp³ fraction (≈55–59%), larger in-plane crystallite size (L_a up to 8.0 nm), and pronounced π–π* shake-up satellites indicated enhanced graphitic ordering when a shorter nanosecond laser was used. These structural differences resulted in substantially lower charge-transfer resistance (0.53–0.79 kΩ·cm³) and larger electroactive surface areas for the porous electrodes compared with foam structured carbon nanomaterials. The results show that, under the selected fabrication conditions, variations in laser processing parameters correspond to differences in graphitic ordering and electron-transfer properties in PEI-derived laser-induced carbon materials. Full article

In this work a study about the behavior of nanomaterial-based innovative transparent electrodes is presented, with a special focus on graphene, for space photovoltaic applications, in particular their transparency and the efficiency of the final device. The efficiency of a solar cell is characterized by referring to Power Conversion Efficiency and External/Internal Quantum Efficiency. Starting from the literature results, it is possible to observe that solar cells realized by innovative nanomaterial-based transparent electrodes show promising results in terms of efficiency in the Earth environment. It is known that the space environment is characterized by extreme conditions including high-energy radiation, strong temperature variations and high vacuum, which can damage materials and, consequentially, influence their performances. Among all the properties like transmittance and sheet resistance, which are the main requirements for a good transparent electrode, could change their value and, therefore, influence the efficiency of the solar cell adopting this kind of electrode. In this paper, a theoretical analysis on the effects of high-energy radiation on the transmittance of graphene layers is given, leading to the observation that in the UV frequency range, it shows a sharp fall. Moreover, the effect of temperature varying is studied by an theoretical analysis on the resistivity of the twisted graphene bilayer. It is possible to observe that, in this configuration, the system moves from a superconductor to a metal, according to temperature and twist angle. This represents a starting point to have good efficiency of solar devices in a space environment by keeping high the transparency of their electrodes. Full article

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive malignancy, characterized by rapid progression, early metastasis, and resistance to conventional therapies. Increasing evidence indicates that the behavior of residual tumor cells is strongly influenced by physicochemical properties of their microenvironment. Surface engineering strategies using nanostructured materials may therefore represent a complementary approach to modulating cancer cell activity. In this study, we investigated whether a graphene oxide (GO) aerosol nanofilm modifies the biological behavior of PDAC cells in vitro. The GO aerosol (4.5 g/L) was characterized using STEM, DLS, zeta potential measurements, LIBS, EDX, and FTIR spectroscopy. Ultrastructural analysis revealed thin, wrinkled GO sheets forming partially overlapping lamellar structures, while physicochemical characterization confirmed a highly oxidized stable nanomaterial. Human PDAC cell lines (BxPC-3 and AsPC-1) were cultured on GO-modified substrates to assess morphology (SEM), metabolic activity (XTT assay), migratory capacity (wound healing assay over 72 h), and expression of genes related to proliferation and epithelial–mesenchymal transition (EMT) by RT-qPCR. GO nanofilm significantly reduced cell viability and inhibited migration in both cell lines. SEM analysis demonstrated shortened cytoplasmic projections and altered membrane integrity. Gene expression profiling revealed cell line-dependent transcriptional responses, including modulation of components of the PI3K/AKT/mTOR pathway and EMT-associated markers. Collectively, our findings demonstrate that GO aerosol nanofilm alters PDAC cell morphology, viability, and migratory behavior in vitro. Surface-mediated modulation of tumor cell activity may represent a promising adjunct strategy for limiting residual cancer cell survival and metastatic potential. Full article

This study examines the effects of graphene oxide (GO) on the hydration behaviour, microstructure, and mechanical properties of Portland cement-based materials. Cement pastes and mortars incorporating GO at dosages of 0.0005%, 0.005%, and 0.05% by weight of cement were analysed through thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), and mechanical strength testing. TGA results indicate that GO exerts a time-dependent influence on cement hydration. At early ages, GO slightly retards hydration, evidenced by lower C–S–H and CH content in GO-containing samples at 2 and 7 days, attributed to water adsorption by its oxygen-containing functional groups. At later curing ages (28–90 days), TGA results show greater C–S–H and CH weight losses in GO-modified samples compared to the reference, consistent with GO acting as a water reservoir and nucleation site. XRD and SEM results confirm that GO incorporation leads to a reduction in CH crystal size, a denser and more homogeneous microstructure, and fewer pores and microcracks. Mechanical tests revealed that GO contents of 0.0005% and 0.05% produced the most significant improvements, with increases of up to 9% in compressive strength and 16% in flexural strength at 90 days compared with the control specimens. In summary, the incorporation of low GO dosages effectively refines cement microstructure, enhances long-term hydration, and improves mechanical performance, demonstrating GO’s potential as a strength- and durability-enhancing nanomaterial for cementitious composites. Full article

MXenes are an emerging class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides with a unique combination of mechanical, electrical, and thermal properties. While MXenes have been extensively studied in electrochemical and materials science contexts, their mechanical behavior and engineering relevance remain comparatively underexplored. This paper provides a mechanically focused synthesis of MXene research, connecting structure, synthesis, processing, mechanical properties, and functional performance to engineering applications. Emphasis is placed on the tunability of tensile, elastic, shear, and thermomechanical properties through controlled variation of composition, surface terminations, and defects. Comparisons with graphene are used to clarify performance trade-offs and application-specific advantages. Key challenges, including environmental stability, moisture sensitivity, durability, scalability, cost, and integration with conventional engineering materials, are critically examined alongside current mitigation strategies. Applications in structural composites, mechanical reinforcement, energy storage, electromechanical systems, and MXene-based sensors and actuators are discussed to demonstrate practical relevance. By framing MXenes as engineerable materials rather than isolated nanomaterials, this work serves as a technical reference and entry point for mechanical engineers and interdisciplinary researchers seeking to design and deploy MXenes in advanced engineering systems. Full article

Volatile Organic Compounds (VOCs) are important indicators of environmental pollution and metabolic activity, making their sensitive and selective detection highly relevant for applications in health monitoring and air quality assessment. Graphene, owing to its exceptional charge transport properties, large surface area, and tunable surface chemistry, is a promising candidate for advanced gas and VOCs sensing. Here we report chemoresistive sensors based on pristine graphene and graphene decorated with platinum (Pt), palladium (Pd), and gold (Au) nanoparticles toward both aromatic (benzene, toluene, and xylene) and non-aromatic (ethanol, methanol, and acetone) vapor compound detection. The detection is achieved at room temperature, and the results demonstrate that graphene functionalized with noble metal nanoparticles shows significant enhancements in sensitivity compared to pristine graphene, mainly against ethanol, toluene and xylene vapors for the Au–graphene sensors. A comparative study with Multi-Walled Carbon Nanotube (MWCNT) sensors decorated with the same type of nanoparticles revealed clear advantages of graphene, attributed to the microstructure and porous structure of graphene powders, which facilitate efficient charge transfer upon vapor adsorption. Full article

The continuous research progress in materials science has enabled the development of advanced nano-materials, including carbon nano-tubes, graphene and metal oxides with specialized properties, which can fundamentally affect the mechanical, thermal and tribological properties of conventional materials when used in the reinforcing phase [...] Full article

Innovations in nanomaterial science, engineering and printing technologies have increasingly driven advances in electrochemical sensing. Screen-printed electrodes (SPEs) have become a versatile, low-cost, and scalable solution for developing portable electrochemical detection platforms. However, their analytical performance remains intrinsically limited by surface area, electron transfer efficiency, and the immobilization of biomolecules. Recent developments in nanostructured materials, ranging from two-dimensional (2D) materials such as graphene, MXenes, and transition metal dichalcogenides, to one-dimensional nanostructures and hybrid nanocomposites, have transformed the signal transduction landscape of SPE-based electrochemical sensors. Integration of nanomaterials into SPEs has successfully transformed their analytical capabilities, but the diversity of materials and modification strategies has made it difficult to consolidate current knowledge in the field. Strategies that integrate nanomaterials via ink formulation, surface modification, or in situ growth have yielded sensors with unprecedented sensitivity, reproducibility, and selectivity across various chemical and biological targets. This review offers a cross-material synthesis of how nanomaterial engineering transforms the electrochemical performance of SPEs. By integrating insights across morphology, interfacial chemistry, and device-level behavior, it establishes a unified perspective that has been missing from the current literature and clarifies the design principles driving next-generation SPE-based sensing platforms. Full article

Environmental pollution constitutes an increasingly complex global challenge, largely driven by industrial expansion and the consequent release of toxic species such as Cd²⁺, Pb²⁺, Cu²⁺, Hg²⁺, Fe³⁺, As³⁺, and Rh³⁺ into natural ecosystems. These contaminants pose significant risks to environmental integrity and public health, motivating the development of analytical technologies capable of sensitive, selective, and reliable detection. In this context, graphene-based electrochemical sensors have emerged as versatile platforms for monitoring a broad range of analytes, particularly in environmental applications involving heavy-metal detection. The intrinsic physicochemical properties of graphene derivatives have enabled low detection limits, rapid response times, and tunable selectivity. Despite analytical advances, critical challenges persist regarding operational stability in complex matrices, inter-batch reproducibility, and robustness to interfering species, which continue to hinder large-scale deployment and real-world applicability. However, challenges remain regarding stability and performance in complex arrays, reproducibility, and resistance to interference, necessitating innovative strategies for functionalization and molecular recognition. This review article establishes a comparative framework based on functionalization strategies (covalent, non-covalent, and hybrid), the chemical nature of graphene (GO, rGO, and doping), and various types of polymers (conductors and insulators), using statistical metrics such as the limit of detection (LOD), linear range, working potential, stability, and interferences, employing a bibliometric analysis using the PRISMA 2020 methodology. This comparative framework enables analysis and explanation of performance trends, and the generation of design and functionalization recommendations for versatile applications, including criteria for reproducibility and sustainability. Full article

The scalable and sustainable production of graphene remains a significant challenge due to the high cost, complex processing, and environmental impact associated with fossil-derived graphite precursors. In this work, we report a biorenewable pathway for producing graphitic carbon from industrial hemp biomass, yielding a plant-derived material called CleanGraphene. This approach provides a renewable and potentially scalable alternative to petroleum- and coal-based graphene production while maintaining competitive structural and electrical performance. CleanGraphene samples are systematically characterized using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) to evaluate crystallographic order, layer stacking, defect density, surface chemistry, and thermal stability. The results show that optimized CleanGraphene materials consist of multilayer graphene-like platelets with compact interlayer spacing (d(002) ≈ 3.36–3.37 Å), extended crystallite coherence lengths (L_c up to ~75 nm), large in-plane sp² domains (L_a exceeding ~200 nm), and relatively low defect densities, indicating well-developed graphitic ordering. Electrical conductivity measurements using a binder-free pelletization method and four-point probe analysis demonstrate that the highest quality CleanGraphene samples achieve conductivities of (8.4–8.6) × 10⁴ S m⁻¹, surpassing leading commercial graphene benchmarks measured under identical conditions. Structure–property correlations confirm that electrical performance is governed primarily by crystallite coherence, defect density, and interlayer stacking order, while surface oxygen content plays a secondary role within an ordered graphitic framework. All CleanGraphene samples exhibit excellent thermal stability, retaining more than 95% mass up to ~800–900 °C under an inert atmosphere. Collectively, these findings establish quantitative quality benchmarks for hemp-derived graphene and demonstrate that biomass-based graphene can achieve electrical and thermal performance comparable to, and in some cases exceeding, conventional commercial products. This work highlights industrial hemp as a promising renewable precursor for the scalable production of high-performance graphitic nanomaterials for electrically and thermally conductive composite applications. Full article

Water pollution, caused by selenium contamination, is a significant global issue due to its toxic effects on humans and animals. Selenium occurs in several oxidation states, among which selenite and selenate are the most mobile and bioavailable forms. Traditional water treatment methods are often limited in efficiency, whereas adsorption offers a simple, cost-effective, and efficient solution. Various adsorbents, including metal and mineral oxides, carbon-based materials (activated carbon, graphene oxide), biosorbents, and nanocomposites, have shown high potential for Se removal. Adsorbent modifications—physical, chemical, or composite—significantly enhance adsorption capacity, selectivity, and material stability. Studies have demonstrated that nanomaterials and nanocomposites, such as MnFe₂O₄, PAA-MGO, magnetic MOFs, and magnetite-based biochars, enable rapid removal of Se(IV) and Se(VI) with high adsorption capacities. Se(IV) is primarily adsorbed through innersphere complexation, while Se(VI) forms weaker outer-sphere interactions, explaining differences in removal efficiency. Factors such as pH, the presence of surface hydroxyl and amino groups, surface charge, and competing ions strongly influence the adsorption process. Multivalent ions reduce Se adsorption efficiency, whereas monovalent ions (NO₃⁻ and Cl⁻) have minimal impact. Modified adsorbents, nanomaterials, and nanocomposites provide sustainable and practical solutions for selenium removal from water, combining high efficiency, selectivity, and reusability, making them suitable for real-world water treatment applications. Full article

This paper presents work on the green synthesis of the graphene quantum dots (GQDs) and carbon dots (CDs) from leaves of Erythrina caffra (E. caffra) using a simple technique to facilitate the carbonization process, from methanol and water extracts of E. caffra leaf, and their evaluation as potential antiviral agents against SARS-CoV-2. Phytochemical profiling of E. caffra leaf extracts exhibited the presence of phenols, alkaloids, steroids/terpenoids, tannins, and flavonoids. FTIR analysis confirmed the incorporation of oxygenated functional groups inherited from the phytochemicals. UV-Vis indicated the presence of secondary metabolites in both extracts and CDs. X-ray diffraction spectra confirmed the amorphous and crystalline nature of synthesized CDs (2.51 nm) from water extracts and GQDs (0.08 nm) from methanol extracts. The CDs and GQDs exhibited respective sizes of 5.5 and 4.0 nm, with a dot-like morphology, and respective zeta potential of +200.0 and −12.6 mV. The results revealed that all extracts and carbon dot formulations exhibited high cell viability (>90%), indicating excellent biocompatibility and minimal cytotoxicity at the tested concentration of 100 mg/mL per sample. The SARS-CoV-2 experiments demonstrated that extracts (MeOH, H₂O) and nanomaterials (CDs-H₂O, GQDs-MeOH) exhibited a virus suppression efficacy of 87.86 ± 4.75%, 87.95 ± 0.77%, 87.95 ± 3.08%, and 94.84 ± 0.94%, respectively. All examined samples demonstrated viral inhibition over 88%. Both extracts and their respective nanomaterials showed that a minimum of 5 μg was required to achieve 50% antioxidant species per sample. The study highlights E. caffra as a sustainable precursor for eco-friendly carbon dot synthesis as potential antiviral and antioxidant candidates. Full article