Search Results (352)

While microparticles can be removed by a filtration step at a drinking water treatment plant (DWTP), engineered nanoparticles (ENPs), which are widely used in industry, commerce and households, pose a major problem due to their special properties, e.g., size, reactivity and polarity. In addition, many ENPs exhibit toxic potential, which makes their presence in drinking water undesirable. Therefore, this study investigated the removal of ENPs in the laboratory and at a pilot-scale DWTP. Eight ENPs were synthesized and tested for stability in different types of water. Only three of them were stable in natural water: cetyltrimethylammonium bromide-coated gold (CTAB/AuNPs), polyvinylpyrrolidone-stabilized gold and silver nanoparticles (PVP/AuNPs, PVP/AgNPs). Their retention on quartz sand, silica gel and fresh anthracite was low, but CTAB/AuNPs could be retained on fresh river sand and thus should not overcome riverbank filtration, while PVP/AuNPs and PVP/AgNPs showed no retention and may be present in raw water. During ozonation, PVP/AuNPs remained stable while PVP/AgNPs were partially degraded. The advanced oxidation process (AOP) was less effective than ozone. PVP/AgNPs were almost completely retained on the pilot plant anthracite sand filter coated with manganese(IV) oxide and ferrihydrite from raw water treatment. PVP/AuNPs passed the filter with no retention. In contrast to PVP/AuNPs, PVP/AgNPs and CTAB/AuNPs were also retained on activated carbon. The integration of a flocculation step with iron(III) salts can improve ENP removal, with PVP/AuNPs requiring higher flocculant doses than PVP/AgNPs. PVP/AuNPs, in particular, are well-suited for testing the effectiveness of water treatment. Further data on the occurrence of stable ENPs in raw water and their behavior during water treatment are needed to perform a risk assessment and derive the measures. Full article

This work investigates the impact of friction stir processing (FSP) on the microstructure and mechanical characteristics of AA 6061 alloy and its composites, which are strengthened with boron nitride nanoparticles and vanadium carbide microparticles. Composite samples were created using different proportions of reinforcing particles, including mono and hybrid composites. The efficacy of FSP as a technological method for enhancing the grain size of AA 6061 alloy and its composites has been proven. Adding reinforcing particles led to enhanced grain refinement, especially when using VC particles, which demonstrated greater efficacy than BN particles; thus, mono composite AA6061/VC shows the highest percentage reduction (94.29%) in grain size. Hybrid composites with a higher concentration of VC particles exhibited a more symmetrical microhardness profile. The microhardness of hybrid composites with a larger concentration of VC particles (40 vol.%BN + 60 vol.%VC) shows the most significant enhancement, with an increase of 51.61%. The Young’s and shear modulus of all composite samples processed by (FSP) had greater values than the wrought AA 6061 alloy. The investigated composite samples, especially 60% BN and 40% VC, enhanced the tribological properties of AA6061 and reduced the wear rate by about 52%. The observed characteristics may be due to BN and VC particles in the hybrid compost. This is because these particles effectively prevent grain elongation and inconsistent movement. This is because reinforcing particles can be tailored to have specific properties for specific applications. Full article

This study introduces a novel paper coating approach using modified zinc oxide (ZnO), providing a comparison with conventional materials used in the paper industry. The research focused on determining the concentration for effective microbial growth inhibition and evaluates the impact of different ZnO types on coated-paper properties, including antimicrobial activity, surface morphology, tensile strength, and water absorption. Specifically, ZnO microparticles (ZnO_ws), ZnO nanoparticles (ZnO_np), and modified ZnO_np (ZnO_np-CaCO₃, with a core–shell structure composed of calcium carbonate [CaCO₃] and nano-zinc oxide) were incorporated into coating formulations at varying concentrations (0 × MIC, 1 × MIC, 2 × MIC, and 3 × MIC, based on minimum inhibitory concentrations [MICs]). The results demonstrated that among all tested microorganisms, ZnO_np-CaCO₃ showed the lowest MIC values. ZnO_np-CaCO₃-coated paper exhibited superior antimicrobial activity against both Gram-positive and Gram-negative bacteria, as well as fungi, outperforming ZnO_ws and ZnO_np. At 1 × MIC, %inhibition for E. coli, S. aureus, and A. niger were 98.3%, 99.1%, and 90.8%, respectively. Additionally, ZnO_np-CaCO₃ coatings caused minimal color change in the paper compared to the other ZnO variants. The coating did not negatively impact the mechanical properties of the paper across all ZnO types and concentrations. Water absorption tests showed increased hydrophobicity with higher ZnO content, with ZnO_np and ZnO_np-CaCO₃ exhibiting greater reductions in water absorption than ZnO_ws. Overall, ZnO_np-CaCO₃ showed strong potential as an antimicrobial agent for paper surfaces, making it ideal for packaging and hygiene products. By partially replacing ZnO_np with inexpensive CaCO₃ core particles, ZnO_np-CaCO₃ delivers enhanced performance, reduced costs, and greater sustainability for large-scale applications. Full article

In recent years, there has been an increasing interest in phase change materials (PCM) based on dulcitol and other sugar alcohols. These materials have almost twice as large latent heat of fusion as other organic materials. Sugar alcohols are relatively cheap, and they can undergo cold crystallization, which is crucial for long-term thermal energy storage. The disadvantage of dulcitol and other sugar alcohols is the solid–liquid phase transition. As a result, the state of matter of the material and its volume change, and in the case of materials modified with microparticles or nanoparticles, sedimentation of additives in liquid PCM can occur. In this study, we obtained shape-stable phase change materials (SSPCM) by co-gelation of starch and dulcitol. To characterize the samples obtained, differential scanning calorimetry (DSC), step-mode DSC, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used, and they were also used to test for shape stabilization. The results show that the obtained systems have great potential as shape-stabilized phase change materials. The sample dulcitol/starch with a 50:50 ratio exhibited the highest heat of cold crystallization, up to 52.90 J/g, while the heat of melting was 126.16 J/g under typical DSC measuring conditions. However, depending on the applied heating program, the heat of cold crystallization can even reach 125 J/g. The thermal stability of all compositions was higher than the phase change temperature, with only 1% mass loss occurring at temperatures above 200 °C, while the phase change occurred at a maximum of 190 °C. Full article

Background. Lipid–polymer hybrid nanoparticles (LPHNPs) offer a promising method for delivering methylprednisolone (MePD) to treat lung inflammation, addressing aggregation issues seen with polymer-only formulations. Objectives. This study aimed to develop LPHNPs for MePD delivery, assessing their physicochemical properties, drug loading, cytocompatibility, and release profiles, ultimately enabling inhalable microparticle-based powder. Methods. The nanoparticles were formulated using α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-g-Rhodamine B-g-poly(lactic acid) (PHEA-g-RhB-g-PLA) and phospholipids DPPC, DOTAP, and DSPE-PEG2000 in a 45:30:25 weight ratio. Their size, redispersion after freeze-drying, drug loading (DL%), and controlled release were evaluated. Cytocompatibility was assessed on 16-HBE cell lines, measuring anti-inflammatory effects via IL-6 and IL-8 levels. Spray drying was optimized to produce microparticles using mannitol (MAN), leucine (LEU), and N-acetylcysteine (NAC). Results. The nanoparticles had a size of 186 nm and a DL% of 2.9% for MePD. They showed good cytocompatibility, significantly reducing IL-6 and IL-8 levels. Spray drying yielded microparticles with a fine particle fraction (FPF) of 62.3% and a mass median aerodynamic diameter (MMAD) of 3.9 µm. Inclusion of LPHNPs@MePD (0.25% w/v) resulted in FPF and MMAD values of 56.7% and 4.4 µm. In conclusion, this study described the production of novel inhalable powders as carriers for MePD-loaded nanostructures with favorable physicochemical properties, cytocompatibility, and promising aerosol performance, indicating their potential as an effective inhalable therapy for lung inflammation with corticosteroids, especially for treating chronic diseases. Full article

Two-component micro-powder injection moulding (2C-μPIM) is a prospective approach for fabricating bi-material micro-components of stainless steel 316L (SS316L) and 3 mol% yttria-stabilised zirconia (3YSZ) at an appealing cost. However, the fundamental challenge lies in preventing the formation of large-scale cracks at the interface of two different materials during sintering. This study investigated how SS316L nanoparticles in bimodally configured SS316L powder that incorporated both nanoparticles and microparticles influenced the sintering of 2C-μPIM-processed miniature bi-materials made of bimodal SS316L and 3YSZ. In this study, feedstocks were developed by integrating monomodal (micro-sized) SS316L powder, three types of nano/micro-bimodal SS316L powders, and 3YSZ powder individually with palm stearin and low-density polyethylene binders. The results indicated that increasing the SS316L nanoparticle content to 45 vol.% caused a 19.5% increase in the critical powder loading in the bimodal SS316L powder as compared to that in the monomodal SS316L powder. The addition of SS316L nanoparticles increased the relative density and hardness of the sintered bi-materials, with the maximum values obtained being 96.8% and 1156.8 HV, respectively. Field emission scanning electron microscopy investigations revealed that adding 15 vol.% and 30 vol.% SS316L nanoparticle contents reduced interface cracks in bi-materials significantly, while 45 vol.% resulted in a crack-free interface. Full article

Micro- and nanoparticles of chitosan and carboxymethyl chitosan were synthesized, both with and without ascorbic acid. Methods were developed to form complexes between these micro- and nanoparticles and plant proteases—ficin, papain, and bromelain. It was demonstrated that the activity of cysteine protease complexes with carboxymethyl chitosan micro- and nanoparticles was higher compared to those with chitosan micro- and nanoparticles. Additionally, the complexes of ficin, papain, and bromelain with chitosan and carboxymethyl chitosan micro- and nanoparticles synthesized in the presence of ascorbic acid exhibited greater proteolytic activity than those formed with particles prepared without ascorbic acid. Molecular docking studies revealed that the amino acid residues of ficin, papain, and bromelain primarily interact with chitosan and carboxymethyl chitosan through hydrogen bonding and hydrophobic interactions. The amino acid residues in the active sites of these enzymes participate in a complex formation, which likely contributes to the increased activity and stability of cysteine proteases in complexes with chitosan and carboxymethyl chitosan micro- and nanoparticles. Full article

Elevated brain iron levels are characteristic of many neurodegenerative diseases. As an iron chelator with short biological half-life, deferiprone leads to agranulocytosis and neutropenia with a prolonged therapeutic course. Its inclusion in sustained-release dosage forms may reduce the frequency of administration. On the other hand, when administered by an alternative route of administration, such as the nasal route, systemic exposure to deferiprone will be reduced, thereby reducing the occurrence of adverse effects. Direct nose-to-brain delivery has been raised as a non-invasive strategy to deliver drugs to the brain, bypassing the blood–brain barrier. The aim of the study was to develop and characterize nanocomposite microspheres suitable for intranasal administration by combining nano- and microparticle-based approaches. Nanoparticles with an average particle size of 213 ± 56 nm based on the biodegradable polymer poly-ε-caprolactone were developed using the solvent evaporation method. To ensure the deposition of the particles in the nasal cavity and avoid exhalation or deposition into the small airways, the nanoparticles were incorporated into composite structures of sodium alginate obtained by spray drying. Deferiprone demonstrated sustained release from the nanocomposite microspheres and high iron-chelating activity. Full article

The use of surface-enhanced Raman spectroscopy (SERS) in liquid solutions has always been challenging due to signal fluctuations, inconsistent data, and difficulties in obtaining reliable results, especially at very low analyte concentrations. In our study, we introduce a new method using a three-dimensional (3D) SERS substrate made of silica microparticles (SMPs) with attached plasmonic nanoparticles (NPs). These SMPs were placed in low-concentration analyte solutions for SERS analysis. In the first approach to perform SERS in a 3D environment, glycerin was used to immobilize the particles, which enabled high-resolution SERS imaging. Additionally, we conducted time-dependent SERS measurements in an aqueous solution, where freely suspended SMPs passed through the laser focus. In both scenarios, EFs larger than 200 were achieved, which enabled the detection of low-abundance analytes. Our study demonstrates a reliable and reproducible method for performing SERS in liquid environments, offering significant advantages for the real-time analysis of dynamic processes, sensitive detection of low-concentration molecules, and potential applications in biomolecular interaction studies, environmental monitoring, and biomedical diagnostics. Full article

When exposed to X-rays, scintillators emit visible luminescence. X-ray-mediated optogenetics employs scintillators for remotely activating light-sensitive proteins in biological tissue through X-ray irradiation. This approach offers advantages over traditional optogenetics, allowing for deeper tissue penetration and wireless control. Here, we assessed the short-term safety and efficacy of candidate scintillator materials for neuronal control. Our analyses revealed that lead-free halide scintillators, such as Cs₃Cu₂I₅, exhibited significant cytotoxicity within 24 h and induced neuroinflammatory effects when injected into the mouse brain. In contrast, cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) nanoparticles showed no detectable cytotoxicity within the same period, and injection into the mouse brain did not lead to observable neuroinflammation over four weeks. Electrophysiological recordings in the cerebral cortex of awake mice showed that X-ray-induced radioluminescence from Ce:GAGG nanoparticles reliably activated 45% of the neuronal population surrounding the implanted particles, a significantly higher activation rate than europium-doped GAGG (Eu:GAGG) microparticles, which activated only 10% of neurons. Furthermore, we established the cell-type specificity of this technique by using Ce:GAGG nanoparticles to selectively stimulate midbrain dopamine neurons. This technique was applied to freely behaving mice, allowing for wireless modulation of place preference behavior mediated by midbrain dopamine neurons. These findings highlight the unique suitability of Ce:GAGG nanoparticles for X-ray-mediated optogenetics. The deep tissue penetration, short-term safety, wireless neuronal control, and cell-type specificity of this system offer exciting possibilities for diverse neuroscience applications and therapeutic interventions. Full article

Silver nanoparticles (Ag NPs) conjugated with amino-functionalized cellulose nanofibrils (NH₂−CNFs) were in situ-prepared by reducing silver ions with free amino groups from NH₂−CNFs. The spectroscopy and transmission electron microscopy measurements confirmed the presence of non-agglomerated nanometer-in-size Ag NPs within micrometer-large NH₂−CNFs of high (20 wt.-%) content. Although the consumption of amino groups during the formation of Ag NPs lowers the ζ-potential and surface charge of prepared inorganic–organic hybrids (from +31.3 to +19.9 mV and from 2.4 to 1.0 mmol/g at pH 7, respectively), their values are sufficiently positive to ensure electrostatic interaction with negatively charged cell walls of pathogens in acidic and slightly (up to pH ~8.5) alkaline solutions. The antimicrobial activity of hybrid microparticles against various pathogens (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans) is comparable with pristine NH₂−CNFs. However, a long-timescale use of hybrids ensures the slow and controlled release of Ag⁺ ions to surrounding media (less than 1.0 wt.-% for one month). Full article

Nickel oxide (NiO) is one of the most popular hydrogenation catalysts. In heterogeneous catalysis, nickel oxide is used, for example, as a suitable methanation catalyst in the Fischer–Tropsch reaction not only for CO hydrogenation but also in the modified Fischer–Tropsch reaction with CO₂. However, CH₄ selectivity and CO₂ conversion strongly depend on NiO micro- (MPs) and nanoparticles’ (NPs) shape, size, and surface area. In this study, the synthesis of NiO micro- and nanoparticles was conducted using the simple solvothermal method. Different morphologies (microspheres, sheet clusters, hexagonal microparticles, and nanodiscs) were prepared using this method with different solvents and stabilizers. The prepared catalysts were tested in the hydrogenation of CO₂ in a gas phase with excellent conversion values and high selectivity to produce CH₄. The best results were obtained with the NiO with disc or sphere morphology, which produced methane with selectivity at a level near 100% and conversion close to 90%. Full article

Eye disorders affect a substantial portion of the global population, yet the availability of efficacious ophthalmic drug products remains limited. This can be partly ascribed to a number of factors: (1) inadequate understanding of physiological barriers, treatment strategies, drug and polymer properties, and delivery systems; (2) challenges in effectively delivering drugs to the anterior and posterior segments of the eye due to anatomical and physiological constraints; and (3) manufacturing and regulatory hurdles in ocular drug product development. The present review discusses innovative ocular delivery and treatments, encompassing implants, liposomes, nanoparticles, nanomicelles, microparticles, iontophoresis, in situ gels, contact lenses, microneedles, hydrogels, bispecific antibodies, and gene delivery strategies. Furthermore, this review also introduces advanced manufacturing technologies such as 3D printing and hot-melt extrusion (HME), aimed at improving bioavailability, reducing therapeutic dosages and side effects, facilitating the design of personalized ophthalmic dosage forms, as well as enhancing patient compliance. This comprehensive review lastly offers insights into digital healthcare, market trends, and industry and regulatory perspectives pertaining to ocular product development. Full article

Xanthan gum (XG) is an exopolysaccharide synthesized by the aerobic fermentation of simple sugars using Xanthomonas bacteria. It comprises a cellulosic backbone with a trisaccharide side chain connected to alternative glucose residues in the main backbone through α (1→3) linkage. XG dissolves readily in cold and hot water to produce a viscous solution that behaves like a pseudoplastic fluid. It shows excellent resistance to enzymatic degradation and great stability throughout a broad temperature, pH, or salt concentration range. Additionally, XG is nontoxic, biocompatible, and biodegradable, making it a suitable carrier for drug delivery. Furthermore, the carboxylic functions of pyruvate and glucuronic acid offer a considerable opportunity for chemical modification to meet the desired criteria for a specific application. Therefore, XG or its derivatives in conjunction with other polymers have frequently been studied as matrices for tablets, nanoparticles, microparticles, and hydrogels. This review primarily focuses on the applications of XG in various oral delivery systems over the past decade, including sustained-release formulations, gastroretentive dosage forms, and colon-targeted drug delivery. Source, production methods, and physicochemical properties relevant to drug delivery applications of XG have also been discussed. Full article

Osteoarthritis (OA) is a debilitating joint disease characterized by cartilage degradation, leading to pain and functional impairment. A key contributor to OA progression is the decline in cartilage lubrication. In physiological conditions, synovial fluid (SF) macromolecules like hyaluronic acid (HA), phospholipids, and lubricin play a crucial role in the boundary lubrication of articular cartilage. In early OA, cartilage damage triggers inflammation, altering SF composition and compromising the lubrication layer. This increases friction between mating interfaces, worsening cartilage degradation and local inflammation. Therefore, early-stage restoration of lubrication (by injecting in the joint different classes of compounds and formulations) could alleviate, and potentially reverse, OA progression. In the light of this, a broad variety of lubricants have been investigated for their ability to reduce friction in OA joints and promote cartilage repair in clinical and preclinical studies. This review examines recent advancements in lubricant-based therapy for OA, focusing on natural, bioinspired, and alternative products. Starting from the currently applied therapy, mainly based on natural lubricants as HA, we will present their modified versions, either in hydrogel form or with specific biomimetic moieties with the aim of reducing their clearance from the joint and of enhancing their lubricating properties. Finally, the most advanced and recent formulation, represented by alternative strategies, will be proposed. Particular emphasis will be placed on those ones involving new types of hydrogels, microparticles, nanoparticles, and liposomes, which are currently under investigation in preclinical studies. The potential application of particles and liposomes could foster the transition from natural lubricants to Drug Delivery Systems (DDSs) with lubricant features; transition which could provide more complete OA treatments, by simultaneously providing lubrication replacement and sustained release of different payloads and active agents directly at the joint level. Within each category, we will examine relevant preclinical studies, highlighting challenges and future prospects. Full article