Beilstein Journal of Nanotechnology最新文献

Nanoparticle-based functionalization has emerged as an effective strategy to enhance the antimicrobial properties of textiles. In this study, silver (Ag⁺), copper (Cu²⁺), and zinc (Zn²⁺) cations are ion-exchanged with Y-type zeolite (CBV-600) and subsequently applied to cotton fabrics using the pad-dry-cure method, with an acrylic resin serving as binder. The resulting functionalized fabrics, containing metal cation concentrations of 1.0-1.5 atom % are evaluated regarding their antimicrobial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), as well as regarding their physicochemical and mechanical properties. Scanning electron microscopy confirms the uniform distribution and successful incorporation of nanomaterials onto the fabric surfaces. Antimicrobial tests reveal significant inhibition of bacterial growth, with silver-based materials demonstrating superior efficacy. Importantly, the antimicrobial effect persists after five washing cycles, demonstrating the durability of the functionalization. This method demonstrates a simple and industry-compatible approach for producing durable antimicrobial cotton fabrics.

In this work, we present the design, fabrication, and study of the optical properties of multilayered metal-dielectric Au/TiO₂ structures. The samples were fabricated using Joule effect evaporation for gold and electron beam evaporation for titanium dioxide. Their structure was designed to have an epsilon-near-zero (ENZ) point at different wavelengths around 800 nm, in order to study their nonlinear response as a function of the resonance conditions around the ENZ point. The characterization of the linear properties of the samples was done using spectrophotometry and spectral ellipsometry. We studied the nonlinear response with the z-scan technique at different incident irradiances using a Ti:sapphire femtosecond laser, enabling us to characterize both the refractive and absorptive contributions to the nonlinear response. Due to the high pulse repetition rate inherent to Ti:sapphire systems and the presence of linear absorption in the samples, cumulative pulse-to-pulse thermal effects may be present. A modified version of the z-scan technique that allowed us to separate the electronic from the thermal contribution was used. A clear enhancement of the nonlinear response was observed for the sample with an ENZ point around the laser wavelength 800 nm with a nonlinear refractive index of n ₂ = 0.103 ± 0.006 cm²·GW^-1, a value that is comparable to other ENZ materials in literature.

Wood tracheids and fibers exhibit diverse structures and shapes across plant species. The hierarchical structure and composition of cellulose, hemicelluloses, and lignin enables wood to withstand high stress. This structural resilience makes wood a versatile material for applications ranging from construction to advanced composites. However, a detailed understanding of how delignification affects softwood tracheid and hardwood fiber morphology is crucial for predicting material behavior and developing modified wood products. This study investigated the overall structural changes due to delignification, in five wood species, namely, spruce, beech, balsa, Douglas fir, and poplar. It additionally provides detailed morphology of delignified single tracheids and fibers. Scanning electron microscopy was used to compare the morphology between untreated and delignified fibers and tracheids. X-ray tomography enabled us to reconstruct high-resolution 3D models of delignified single tracheids or fibers, providing information on the pit arrangements. Moreover, delignification resulted in facilitated separation of fibers and tracheids and frayed wall appearance. We observed similar tracheid/fiber diameters and wall thicknesses for all five wood species. These findings enhance our understanding of the wood fiber and tracheid structures across species and the effects of delignification. The 3D models provide a valuable resource for (1) understanding interspecies differences of fibers and tracheids, (2) optimizing the use of delignified wood in industrial applications (including bio-based and bio-inspired materials), and (3) physical modeling of wood regarding questions of wood biomechanics and water management.

Gold nanoparticles (AuNPs) supported on reduced graphene oxide (AuNPs/rGO) were demonstrated to be a highly reactive catalyst for the selective α,β-oxidative dehydrogenation (ODH) of N-alkyl-4-piperidones, using N-methyl-, N-ethyl- and N-benzyl-4-piperidone. The substrate N-methyl-4-piperidone represents a pharmaceutically relevant system as its reaction product N-methyl-2,3-dihydropyridin-4(1H)-one is highly valuable (>1000 €·g^-1) in contrast to the inexpensive starting material (0.15 €·g^-1). Various synthesis methods were employed to prepare AuNPs supported on different carbon materials, including reduced graphene oxide (rGO), activated carbon (AC), and carbon black (CB), to investigate the influence of the carbon support on the catalyst performance. As stabilizing agents for the AuNPs, citrate (Cit) and the polyoxometallate [SiW₉O₃₄]^10- (SiW₉) were used. Among the tested catalysts, the rGO-supported ones, Au-Cit/rGO, Au-SiW₉/rGO, and Au@SiW₉/rGO exhibited the highest catalytic activity for the selective oxidation reaction despite containing the lowest gold loading. These findings highlight the exceptional performance of rGO as a support for AuNP catalysts and provide valuable insights for designing efficient Au-based systems for the dehydrogenation of β-N-substituted saturated ketones and other fine chemical applications.

Time of flight secondary ion mass spectrometry (ToF-SIMS) was used to probe the chemistry of graphene grown on copper foil substrates by chemical vapour deposition (CVD) under various growth conditions. The surface sensitivity, mass resolving power, and imaging capability of ToF-SIMS allow us to explore variations in the chemical species present on the graphene surface, as well as in three dimensions under the graphene. In this way, we can observe the impact that variations in the chemical composition of the copper foil have on the growth of the graphene; in particular, the accumulation of contaminations present in the copper foil, which has implications for the potential electrical properties of the graphene. We also observe variations in the permeation of oxygen underneath the graphene layers, resulting in oxidation of the copper substrate, depending on processing conditions employed and the chemical species present on the surface. This has implications for the gas permeation barrier properties of this material, graphene transfer mechanisms, as well as the effectiveness of using the oxidation of the copper foil as a rapid graphene quality control method. These results highlight the significance of understanding the role of trace contaminants and elemental distributions within the catalyst in conjunction with growth parameters for optimised CVD of graphene layers.

Poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) exhibits a range of unique physical properties that are critical for its diverse applications in photonics, optoelectronics, memory devices, and sensing technologies. In this study, we investigate the thermochromic behavior of PAZO thin films, focusing on the relationship between the structural organization of the polymer side chains and temperature-induced optical changes. By combining experimental spectroscopic techniques with theoretical modeling, we demonstrate that the thermochromic response of PAZO films is strongly influenced by molecular aggregation, film thickness, and thermal treatment conditions. The observed changes in optical properties suggest that this response is governed by temperature-induced modulation of molecular ordering and aggregation state, which in turn alters the electronic transitions responsible for light absorption. Theoretical calculations further support these findings, indicating that temperature-dependent intermolecular interactions and conformational changes play a significant role in shaping the optical behavior of the films. These results provide new insights into the structure-property relationships underlying thermochromism in azopolymer thin films and offer valuable guidelines for the design of thermally responsive photonic materials.

Nanotechnology is revolutionizing different sectors such as medicine, energy, defence, and environmental science by enabling the development of materials and technologies with exceptional precision and efficiency. From advanced drug delivery systems to clean energy solutions, the applications of nanotechnology are diverse and transformative. However, these innovations are accompanied by complex challenges regarding safety and sustainability for both the nanoscale materials themselves and for the products containing them. The growing complexity of engineered nanomaterials calls for proactive strategies to mitigate potential risks while maintaining their functional benefits. The "Safe and Sustainable by Design" (SSbD) concept addresses these challenges by embedding safety measures and sustainability considerations into the earliest stages of material development. Advances in machine learning (ML) and artificial intelligence (AI) have further enhanced the effectiveness of SSbD by providing predictive modelling, risk assessment, decision-making tools, and the ability to computationally screen candidate materials before producing them. This perspective article highlights how ML and AI are driving the evolution of SSbD in nanotechnology, focussing on predictive toxicology, materials informatics, lifecycle analysis, and the pivotal role of digital twins. It also explores current challenges, emerging opportunities, and the path forward for integrating ML/AI-driven SSbD frameworks into regulatory and industrial practices.

Cancer remains a significant global health burden, responsible for 16.8% of all deaths and 30.3% of premature mortality due to noncommunicable diseases, and continues to be one of the leading causes of death worldwide despite medical progress. Conventional treatment methods such as surgery, chemotherapy, and radiotherapy often face challenges such as systemic toxicity, drug resistance, and poor tumour selectivity. In response to these limitations, nanotechnology-based drug delivery systems have gained prominence for enhancing solubility, improving molecular stability, enabling controlled drug release, and prolonging systemic circulation, offering superior therapeutic outcomes over traditional approaches. Among these innovations, charge-reversible nanocarriers have attracted considerable attention due to their ability to overcome physiological and pathological barriers in the tumour microenvironment (TME) by altering their surface charge in response to specific stimuli, which enhances drug targeting while reducing off-target effects. These carriers leverage triggers such as changes in pH, enzymatic activity, redox conditions, temperature, light, ultrasound, X-rays, and magnetic fields to enable intelligent and controlled release of therapeutics. This review examines the crucial role of surface charge in cellular uptake and intracellular transport, highlighting recent advances that demonstrate improved targeting, reduced systemic toxicity, enhanced cellular internalisation, and the potential for integrated approaches, including combination therapies and theranostics. Despite these promising developments, challenges related to nanocarrier stability, safety, manufacturing scalability, and regulatory approval still impede clinical translation. Nevertheless, emerging trends in nanocarrier design, the advancement of personalised medicine, and integration with therapies (e.g., immunotherapy) underscore the transformative potential of charge-reversible nanocarriers in revolutionising cancer treatment and improving patient outcomes.

In contemporary research, there is a clear emphasis on the physicochemical characteristics and effectiveness of nanoliposomal (NLs) formulations. However, there has been minimal focus on elucidating nano-bio interactions and understanding the behavior of these formulations at organ and cellular levels. Specifically, it is widely recognized that when exposed to biological fluids, nanodelivery systems, including NLs, rapidly interact with various biomolecules which have a significant impact on the functionality and fate of the nanosystems but also influence cellular biological functions. Hence, the primary objective of this study was to elucidate the evolution of physicochemical characteristics and surface properties of NLs in biorelevant media. Additionally, in order to point out the influence of specific characteristics on the brain targeting potential of these formulations, we investigated interactions between NLs and blood-brain barrier (BBB, hCMEC/D3) and neuroblastoma cells (SH-SY5Y) under different conditions. The results obtained from comparative in vitro cell uptake studies on both cell culture lines after treatment with three different concentrations of fluorescently labelled NLs (5, 10, and 100 μg/mL) over a period of 1, 2, and 4 h showed a time- and concentration-dependent internalization pattern, with high impact of the surface characteristics of the different formulations. In addition, transport studies on hCMEC/D3/SH-SY5Y co-cultures confirmed the successful transport of NLs across the BBB cells and their subsequent uptake by neurons (ranging from 25.17% to 27.54%). Fluorescence and confocal microscopy micrographs revealed that, once internalized, NLs were concentrated in the perinuclear cell regions.