Search Results (1,466)

The present study introduces a novel two-step multi-analytical approach for studying lustre ceramics, aiming to minimize damage to valuable artifacts. The method combines a completely non-destructive preliminary micro-X-ray fluorescence (micro-XRF) analysis, providing semi-quantitative information and elemental mapping, with micro-destructive transmission electron microscopy (TEM) for detailed nanoparticle (NP) morphology studies on selected areas. Diffuse reflectance spectroscopy (DRS) is also employed as a non-destructive method to quantify lustre colour. This approach was applied to 20 samples of 9th- to 12th-century AD lustre ceramics from the Deraheib site in Northern Sudan. The research aimed to verify the lustre technique, characterize lustre properties (nanoparticle size, colour), and identify the ceramic production center based on glaze composition. The results from micro-XRF and TEM confirmed the presence of silver (Ag) and copper (Cu) in the lustre, with Ag NPs having a median size of 8 nm. Semi-quantitative micro-XRF analysis of the glaze indicated a composition rich in lead and tin oxides (PbO and SnO₂, 5%–15%) and magnesium oxide (MgO, 3%). This composition strongly correlates with published data for lustre ceramic production in Basra, Iraq, suggesting it as the likely origin, and ruling out Fustat, Egypt. Full article

This study investigates the preparation and characterization of tin micro- and nanoparticles with an emphasis on phase-transformation-induced particle formation and chemical purity. Microparticles were generated through repeated phase transformations between β-Sn (white tin) and α-Sn (gray tin), exploiting the associated volumetric changes to induce fragmentation and particle size reduction. The evolution of particle size distribution was systematically analyzed as a function of transformation cycles. The data were analyzed using the modified Johnson–Mehl–Avrami–Kolmogorov equation, and the saturation particle size corresponds to the grain size of the original tin sheet. The phase transformation was induced homogeneously by α-Sn particles and heterogeneously by InSb, and the results were comparable. The influence of the surrounding atmosphere was studied. The increase in oxygen content during repeated phase transformation was measured. In parallel, tin nanoparticles were synthesized via a solution-based route using ammonium hexachlorostannate as a precursor. The nanoparticles precipitated from this solution at mild temperatures during the β-Sn to α-Sn transformation at 13.2 °C. Both micro- and nanoparticles were characterized in terms of morphology and size distribution. The results provide insight into the relationship between phase transformation and particle size reduction mechanisms, and offer a controllable pathway for the preparation of tin particles across micro- and nanoscale regimes. Full article

The rapid growth of electric vehicles and electrified systems has increased the risk of bearing failures due to combined mechanical and electrical stresses. This study investigated the performance of hexagonal boron nitride nanoparticle-enhanced lithium grease under electrified conditions. Experiments based on a Taguchi L9 orthogonal array were conducted on deep groove ball bearings using a full-scale test rig at 1200 rpm with varying loads (100–300 N), currents (6–10 A), and hBN concentrations (0.1–1 wt.%). The tribo-electrical performance of nano-enhanced grease was compared with the base grease and commercial grease. It was observed that the base grease exhibited superior performance with a lower current flow, reduced vibration, and minimal surface degradation. In contrast, the hBN-enhanced grease exhibited inferior tribo-performance, with high vibrations and surface damage in electrified conditions. The surface analysis revealed features morphologically similar to white etching areas and micro-pitting. The FTIR results indicated grease degradation, while ICP-OES confirmed higher wear debris generation in the commercial and hBN-added greases. The present work indicates that additives like hBN nanoparticles do not necessarily improve performance under electrified conditions, making it important to consider the type of additives to be added during lubricant formulation. Thus, the findings emphasize the importance of lubricant formulation for controlling electrically induced bearing failures and provide insights for developing advanced greases for electric machinery applications. Full article

Copper azides are promising energetic materials for miniaturized pyrotechnic devices and micro explosive trains owing to their short detonation growth distance and high initiation energy. However, controllable preparation of copper nanoparticle precursors and their in situ conversion to copper azides under mild conditions remains challenging. In this study, copper nanoparticles were synthesized via a coordination-assisted aqueous reduction method at room temperature under air atmosphere using nitrilotriacetic acid disodium salt (NTA·H·2Na) as the complexing agent. The resulting nanoparticles were pressed into polyester rings to construct confined precursor structures, and copper azide micro-charges were prepared through in situ gas–solid reaction with HN₃ gas generated from NaN₃ and concentrated phosphoric acid at 60 °C. SEM characterization revealed that the morphological evolution of copper azides followed a three-stage pattern: “product island nucleation, branch/block coalescence growth, and continuous product layer formation and structural reconstruction”. Detonation velocity tests using the electrical probe method showed an average value of (5.10 ± 0.07) × 10³ m/s. Flyer impact initiation tests demonstrated that, with a charge thickness of 1.00 mm, both a 30 μm polyimide flyer and a 40 μm titanium flyer could successfully initiate a HNS–IV explosive. The preparation methodology and performance characterization established in this work provide an experimental basis for the application of copper azides in micro-initiation systems. Full article

Head and neck squamous cell carcinoma (HNSCC) remains one of the most aggressive and heterogeneous malignancies worldwide, characterized by high rates of locoregional recurrence, metastatic dissemination, and therapeutic resistance. Angiogenesis plays a central role in tumor progression by supporting vascular remodeling, hypoxia adaptation, invasion, immune evasion, and metastatic spread. In HNSCC, angiogenic activation is regulated through complex interactions involving hypoxia-inducible factors, vascular endothelial growth factor (VEGF) signaling, stromal remodeling, inflammatory pathways, and epigenetic mechanisms within the tumor microenvironment. Recent evidence has also highlighted the role of non-coding RNAs, particularly microRNAs, and exosome-mediated communication in modulating angiogenic and immune-related signaling pathways. Although antiangiogenic therapies, including monoclonal antibodies and tyrosine kinase inhibitors, have demonstrated biological activity in HNSCC, their clinical efficacy remains limited by tumor heterogeneity, adaptive resistance mechanisms, toxicity, and the lack of validated predictive biomarkers. Several emerging therapeutic strategies are under preclinical or early clinical investigation in HNSCC, including miRNA-based approaches, nanoparticle-assisted delivery systems, vascular normalization concepts, and combinations with immune checkpoint inhibitors; however, robust clinical evidence for most of these strategies remains limited, and their translation to routine practice requires further validation. This review provides a comprehensive overview of the molecular mechanisms regulating angiogenesis in HNSCC and critically discusses current and emerging pharmacological strategies targeting these pathways. Particular emphasis is placed on VEGF/VEGFR signaling, the integration of miRNA and exosome biology, resistance mechanisms, and translational perspectives for biomarker-guided personalized therapy. The novelty of this review lies in the systematic integration of miRNA- and exosome-mediated angiogenic regulation, therapeutic resistance pathways, and precision medicine strategies into a unified pharmacological framework, addressing gaps not fully covered by prior reviews focused primarily on VEGF-targeted agents. Full article

Extracellular vesicles (EVs) have become a key area of research, as scientists study their role in various biological processes. These vesicles appear to play a key role in the use of mesenchymal signaling cells (MSCs, formerly known as mesenchymal stem cells) to treat various diseases, such as osteoarthritis (OA), and other degenerative conditions. In our experiments, we examined EVs formed by canine mesenchymal signaling cells (MSCs) to identify them according to current guidelines and define their content, particularly the microRNA (miRNA) they contain, for future research projects. After obtaining the EVs, we demonstrated via Western blotting and transmission electron microscopy that the nanoparticles visible in the nanotracking analysis were positive for CD9 and ALIX and positive for CD9 and CD81, respectively. Markers for nanoparticles that do not represent extracellular particles—tested here as cytochrome C for mitochondrial particles and histones for nuclear particles—were negative. Finally, we detected a total of 85 different miRNAs in the negative controls. To determine the potential influence of various cell stimulations intended to induce osteoarthritis (e.g., interleukin-1β stimulation) or a possible treatment (e.g., shockwave therapy), or the influence of ITS prior to extracellular vesicle extraction, we detected a total of 208 different miRNAs. These results demonstrate how canine EVs from MSCs can be detected in vitro and how the EVs’ miRNA profile changes after stimulation of the producing cells. This information may provide valuable insight into the understanding and treatment of osteoarthritis. Additionally, we demonstrated that using ITS instead of FCS to produce EVs should be reconsidered due to the significant change in miRNA expression levels. Full article

In recent decades, plastic consumption has risen across various industries and everyday products, leading to greater plastic use and the generation of waste, which results in the leaching of micro- and nanoplastics into the environment. This review summarizes recent analytical methods for the detection of nanoplastics (NPs) in several marine matrices, divided into three main stages: extraction, separation, and identification. The literature reviewed indicates that chemical and enzymatic digestion are the most commonly used procedures for the extraction step. For the separation step, flotation, filtration, and centrifugation are the most used techniques. Finally, two groups of techniques may be used for the identification step. The first category consists of methods used for qualitative identification, with spectroscopic methods such as Raman and FTIR being the most frequently used. The second category comprises those used for the quantitative analysis of NPs, where fluorescence-based methods and nanoparticle tracking analysis are increasingly used for this assessment. Despite these advances, significant challenges remain, such as matrix interferences caused by salinity and organic matter, low environmental concentrations of NPs, and the lack of standardized protocols. This review highlights the need for standardized protocols, validated reference materials, and integrated multi-technique approaches to improve the comparability of nanoplastics measurements in marine environments. Full article

Exosomes are small vesicles released by cells that have attracted growing interest as drug delivery vehicles, particularly for brain diseases, where getting therapeutics across the BBB remains a fundamental problem. While conventional platforms such as liposomes, polymeric nanoparticles, and viral vectors often suffer from immune clearance and poor brain accumulation, engineered exosomes leverage natural cellular transport mechanisms to cross the BBB, protect cargo from degradation, and enable biocompatible interactions with target cells. This review takes a mechanistic and translational look at how exosomes are being engineered for CNS disorders, with a particular focus on glioblastoma. We cover exosome biogenesis through ESCRT-dependent and ESCRT-independent pathways, and how the competition between Rab27-driven secretion and Rab7-driven lysosomal degradation determines how many exosomes a cell releases, which has direct consequences for therapeutic production. We then discuss cargo loading strategies, from genetic approaches where donor cells are engineered to package specific molecules during biogenesis to physical methods like electroporation and sonication applied to isolated vesicles, alongside surface modification techniques for directing exosomes toward specific cell types. In glioblastoma, engineered exosomes have shown real promise for delivering chemotherapeutics across the BBB, targeting glioma stem cells, enabling CRISPR-based gene editing, and functioning as combined treatment and imaging tools. Applications in stroke and neurodegenerative diseases, where engineered exosomes carrying microRNAs and neuroprotective cargo have produced encouraging preclinical results, are also discussed. Scalable manufacturing and consistent targeting remain the hardest unsolved problems, and we outline emerging approaches including bioreactor-based production, programmable cargo loading, and patient-specific exosome design that are beginning to address these gaps. Overall, the progress reviewed here suggests that engineered exosomes are moving from an interesting biological concept toward a practically viable platform for CNS drug delivery. Full article

The emergence of organic–inorganic hybrid composites integrating magnetic nanoparticles (MNPs) with polymers has been an important advancement in modern biological research. Among these systems, magnetic sodium alginate (SA)-based hydrogels (MSABHs), produced by embedding MNPs within an SA framework, exhibit remarkable potential for biomedical applications owing to their high biocompatibility, rapid magnetic response, controllable spatiotemporal behavior, and remote, non-invasive operation. Under the influence of an alternating magnetic field (AMF), MSABHs can exhibit various responses, including deformation, motion, and thermal generation, which are highly valuable for diagnostic and therapeutic medical applications. This review first outlines the key studies on SA and MNPs, along with the various synthesis routes used to fabricate MSABHs. Subsequently, the discussion primarily focuses on their versatile biomedical applications, including tissue engineering, targeted drug delivery, thermotherapy, imaging, and micro-robotics, followed by an evaluation of current challenges and prospects for future improvement. Through this comprehensive examination and synthesis, the review aims to further reveal the full potential of MSABHs and broaden their applications in the biological domain. Full article

Poly(3,4-ethylenedioxythiophene) (PEDOT)-based gels have emerged as a prominent class of functional conductive materials, owing to their unique electromechanical coupling characteristics that integrate electrical functionality and mechanical adaptability. This review systematically elucidates the electromechanical properties of PEDOT-derived gels—defined as the synergistic response of electrical behaviors (conductivity, carrier mobility, electrochemical stability) and mechanical performances (flexibility, stretchability, tensile strength, bending resistance)—under mechanical deformation, as well as their mutual regulatory mechanisms. Focusing on how preparation processes and structural regulation modulate these electromechanical properties, this work first introduces the development history, intrinsic conductive mechanisms, and inherent electromechanical characteristics of PEDOT. It then systematically summarizes mainstream synthesis methods, analyzing their effects on balancing mechanical flexibility and electrical conductivity. Addressing the brittleness and poor electromechanical stability of pure PEDOT, this review further explores composite synergistic mechanisms with conductive/non-conductive polymers, metallic materials, inorganic nanoparticles, and biomaterials, clarifying how interfacial interactions optimize mechanical deformability while preserving or enhancing electrical performance. Finally, it summarizes the applications of PEDOT-based composites in electromechanically compatible fields including flexible sensing, micro/nano patterning, implantable biomedicine, anti-corrosion protection, and energy storage. This review aims to clarify the connotation of PEDOT’s electromechanical properties, refine the focus of relevant research, and provide a theoretical basis for designing high-performance PEDOT-based gels with balanced electromechanical properties. Full article

Concerns about human exposure to micro- and nanoplastics (MNPLs), particularly nanoplastics (NPLs), have intensified in recent years. Consequently, there is a growing need for validated quantitative analytical methods capable of assessing NPLs in complex human biological matrices. Current approaches for NPL analysis are still limited by the absence of standardised protocols, difficulties in avoiding background contamination, and challenges associated with the selective identification and quantification of polymer-specific nanoparticles. Moreover, most common approaches for quantification by particle counting cannot be applied for NPLs < 500 nm. In this study, we developed and validated an analytical method for the detection and quantification of NPLs in human faeces. As an initial step, polyethylene (PE) and polypropylene (PP) nanoparticles (NPs) were synthesised using bottom-up methods and characterised by dynamic light scattering (DLS) and electron microscopy (SEM and TEM). To optimise and assess the extraction, synthetic faeces were prepared and used in spiking experiments to avoid background contamination from plastics. Two digestion strategies were evaluated: (i) Fenton’s reagent followed by strong acid digestion, and (ii) alkaline digestion. Quantitative determination of polymer-specific NPLs was performed by size-exclusion liquid chromatography coupled with high-resolution mass spectrometry and atmospheric-pressure photoionization (SEC-APPI-HRMS). Polymer identification was based on characteristic monomer-loss patterns and Kendrick Mass Defect analysis. Fenton-based digestion showed superior performance, yielding recoveries about 55–66% for PE and 59–61% for PP. The validated method achieved limits of detection and quantification of 0.015 and 0.058 μg/kg for PE, and 0.025 and 0.083 μg/kg for PP, respectively. Precision, expressed as %RSD, was 10.1% for PE and 20.1% for PP. These results demonstrate that SEC-APPI-HRMS combined with Fenton-based digestion provides a sensitive and reliable approach for the quantification of polymer-specific NPLs in human faeces. The method represents an important advance for human biomonitoring studies and supports future research aimed at assessing human exposure and the potential health risks associated with nanoplastics. Full article

Superhydrophobic antibacterial coatings offer an effective approach to overcoming the limitations of single anti-adhesion or bactericidal strategies; however, it remains a great challenge to develop such coatings with long-term durability and high bactericidal performance. In this study, a ZT/PDMS composite coating was successfully fabricated by directly mixing ZnO@TiO₂ with PDMS. Benefiting from the low surface energy of polydimethylsiloxane (PDMS) and the coral-like micro/nanostructured rough morphology generated by the incorporation of ZnO@TiO₂ nanoparticles, the coating exhibited excellent superhydrophobic properties, with a water contact angle of 153.5°. The proposed fabrication method showed good adaptability to various substrates, and the resulting coating demonstrated outstanding durability and self-cleaning performance. Notably, the coating retained superhydrophobicity after six abrasion cycles, and the water contact angle remained above 140° after immersion in solutions with pH ranging from 1 to 13 for 7 days. The ZT/PDMS composite coating achieved an antibacterial adhesion rate of 87.98% and 80.11% against Acinetobacter baumannii (A. baumannii) and Staphylococcus aureus (S. aureus), respectively. Under UV and visible light irradiation, its bactericidal efficiency exceeded 90%. The excellent antibacterial performance of the coating was attributed to the synergistic effects of anti-adhesion, active sterilization (Zn²⁺ release and ROS generation), and self-cleaning. This study provides a facile and effective strategy for the development of efficient and durable multifunctional antibacterial coatings. Full article

This work describes the preparation of PTFE (polytetrafluoroethylene)/SiO₂ (silicon dioxide)–ER (epoxy resin)/FR (fluorosilicone resin) superhydrophobic coatings using the spray method to improve the anti-icing and de-icing performance of transmission line insulators. The coatings exhibit a consistent fluorine distribution (32.86 wt%), which enhances their low surface energy, alongside SiO₂ nanoparticles that occupy the interstices between PTFE particles, resulting in a dense micro- and nanoscale hierarchical structure. Consequently, the coatings have good superhydrophobicity, featuring a contact angle of 173.9° and roll angle of 1.2°. Following 66 days of UV irradiation, the contact angle remains above 150°, and the roll angle is approximately 15°, accompanied by a slight increase in ice adhesion strength. Following 26 freeze–thaw cycles, the contact angle stabilizes at around 157°, showing good environmental durability. Natural icing studies validate the coatings’ good anti-icing and de-icing efficacy: in comparison to common insulators, the coated insulators demonstrate a 14.2% reduction in ice accretion weight and a 67.7% reduction in maximum ice ridge length. Full article

Segmental bone defects and age-related osteoarthritis (OA) are clinically challenging in terms of treatment. Although preclinical studies have demonstrated efficacy for bone defect healing and OA using ex vivo gene therapy or biomaterial sustained-release delivery, few such treatments have translated into clinical therapies due to safety concerns. Bone morphogenetic proteins belong to the transforming growth factor β (TGFβ) superfamily and are effective in bone and cartilage regeneration/repair. Among BMPs, BMP4 is not only effective in promoting bone and cartilage repair but also promotes stem cell renewal potential and exhibits anti-aging effects. Therefore, the aim of this study is to investigate whether human BMP4 mRNA encapsulated in lipid nanoparticles (hBMP4 mRNA/LNP) can promote bone and cartilage repair. In vitro data demonstrated that hBMP4 mRNA/LNP-treated human MSCs secreted BMP4 protein, as detected by ELISA, and enhanced osteogenic differentiation. In vivo results demonstrated that hBMP4 mRNA/LNP at a 50 µg dose promoted limited new bone formation only at 2 weeks after creation of defect in critical-sized calvarial bone defects in aged mice when delivered using fibrin sealant hydrogel, as revealed by micro-CT and histology. However, intra-articular injection (IA) of lower doses (2.5 and 5 µg) in aged mice knee joints prevented cartilage loss, as demonstrated by micro-CT; decreased OARSI histology scores; and improved cartilage-specific matrix COL2. hBMP4 mRNA/LNP at a 5 μg dose significantly increased SOX9⁺ cells per normalized cartilage area as well as the percentage of SOX9⁺ cells in the cartilage area. hBMP4 mRNA/LNP treatment showed a trend of pain alleviation and did not change serum hyaluronic acid levels. In conclusion, human BMP4 mRNA encapsulated in lipid nanoparticles improved cartilage repair and delayed cartilage degeneration in aged mice, while having a limited effect on bone healing, even at a higher dosage. These results suggest that hBMP4 mRNA encapsulated with lipid nanoparticles represents a promising treatment for age-related OA. Full article

Extracellular vesicles (EVs) have attracted growing attention for their diagnostic and prognostic potential as they carry molecular cargo such as DNA, RNA, proteins and lipids derived from their cells of origin. While EV research has traditionally focused on blood, this study explicitly explored saliva as a promising, non-invasive sample matrix for EV isolation and biomarker discovery. Six different EV isolation methods were compared for their ability to recover salivary small EVs suitable for downstream DNA and microRNA analysis. Nanoparticle tracking analysis (NTA) revealed variation in vesicle sizes, concentrations and surface charges across all tested EV isolation approaches. In addition to being the fastest and simplest isolation method, the miRCURY Exosome Isolation kit—serum and plasma from Qiagen (ExiQ) also resulted in the highest EV yields with average particle sizes of ~130 nm. Western blot analysis further verified the presence of EV-specific markers (CD9, Alix) and no detectable signal for ApoA1 as an indicator for lipoprotein contamination, underscoring the purity of ExiQ-isolated vesicles. Always applying the same protocol for parallel DNA and RNA isolation on vesicles extracted by various methods, differences in DNA and RNA yields were observed across the evaluated isolation kits. ExiQ-isolated EVs showed the best recovery for both nucleic acid types. Notably, nuclease treatment of isolated EVs revealed that substantial amounts of DNA were present on the EV surface, whereas microRNA was predominantly localized within the vesicles. The present study, extensively comparing different EV isolation methods, demonstrates that salivary EVs are a viable source for non-invasive diagnostics and suggests the miRCURY Exosome Isolation kit—serum and plasma from Qiagen (ExiQ) to be a good choice for integration in future salivary EV-based diagnostic assays given its simplicity, speed and excellent performance. Full article