Nanometer Size Research Articles

A promising eco-sustainable wound dressing based on cellulose extracted from Spartium junceum L. and impregnated with Glycyrrhiza glabra L extract: Design, production and biological properties

Glycyrrhiza glabra extract is widely known for its antioxidant and anti-inflammatory properties and can improve the wound healing process. The aim of this work was to shorten the time of the healing process by using an eco-sustainable wound dressing based on Spanish broom flexible cellulosic fabric by impregnation with G. glabra extract-loaded ethosomes. Chemical analysis of G. glabra extract was performed by LC-DAD-MS/MS and its encapsulation into ethosomes was obtained using the ethanol injection method. Lipid vesicles were characterized in terms of size, polydispersity index, entrapment efficiency, zeta potential, and stability. In vitro release studies, biocompatibility, and scratch test on 3T3 fibroblasts were performed. Moreover, the structure of Spanish broom dressing and its ability to absorb wound exudate was characterized by Synchrotron X-ray phase contrast microtomography (SR-PCmicroCT). Ethosomes showed a good entrapment efficiency, nanometric size, good stability over time and a slow release of polyphenols compared to the free extract, and were not cytotoxic. Lastly, the results revealed that Spanish broom wound dressing loaded with G. glabra ethosomes is able to accelerate wound closure by reducing wound healing time. To sum up, Spanish broom wound dressing could be a potential new green tool for biomedical applications.

Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

ADVANCEMENTS IN THERAPEUTICS: THE ROLE OF NANOPARTICLE-INFUSED HYDROGELS IN REVOLUTIONIZING DRUG DELIVERY

Nanoparticles loaded hydrogel has emerged as a promising strategy in the field of drug delivery systems, offering unique advantages in terms of controlled release, enhanced bioavailability, and targeted delivery of therapeutic agents. Nanoparticles, typically ranging from 1 to 100 nanometers in size, serve as carriers for drugs, encapsulating them within their matrix and protecting them from degradation. Hydrogels, on the other hand, are three-dimensional cross-linked networks of hydrophilic polymers capable of absorbing and retaining large amounts of water. It aims to provide a comprehensive understanding of nanoparticles loaded hydrogel in drug delivery systems by elucidating the relationship between nanoparticles and hydrogels and their synergistic effects on drug delivery. Firstly, the properties of nanoparticles, including size, surface charge, and composition, significantly influence their interactions with hydrogels and the encapsulation efficiency of drugs. Secondly, the unique characteristics of hydrogels, such as tunable swelling behavior and biocompatibility, complement the stability and sustained release kinetics of nanoparticles.Furthermore, the incorporation of nanoparticles into hydrogel matrices enhances their mechanical strength and allows for the development of stimuli-responsive systems, enabling on-demand drug release triggered by external stimuli such as pH, temperature, or magnetic fields. The synergistic combination of nanoparticles and hydrogels opens up new avenues for the design of advanced drug delivery systems with improved therapeutic efficacy and reduced side effects. In conclusion, nanoparticles loaded hydrogel represents a promising platform for the development of next-generation drug delivery systems, offering unprecedented control over drug release kinetics and targeting capabilities. This review highlights the importance of understanding the interplay between nanoparticles and hydrogels in optimizing the performance of drug delivery systems for various biomedical applications.

Spark Discharge Aerosol-Generated Copper-Based Nanoparticles: Structural & Optical Properties; Application on the Antiviral (SARS-CoV-2) and Antibacterial Improvement of Face Masks.

Nanoparticle formation by Spark Discharge Aerosol Generation offers low-cost fabrication of nanoparticles, without the use of chemicals or vacuum. It produces aerosol particles of a few nanometers in size with high purity. In this work, copper-based -CuO (tenorite) and Cu- nanoparticles are produced, characterized and used to modify face mask air filters, achieving the introduction of antibacterial and antiviral properties. A range of characterization techniques have been employed, down to the atomic level. The majority of the particles are CuO (of a few nanometers in size that agglomerate to form aggregates), the remainder being a small number of larger Cu particles. The particles were deposited on various substrates, mainly fiber filters in order to study them and use them as biocidal agents. On face masks, their antibacterial activity against Escherichia coli (E.coli) results in a 100 % decrease in bacteria cell viability. Their antiviral activity on face masks results in a 90 % reduction of the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) viability, 15 minutes post the application of the virus stock solution. This highlights the effectiveness of this approach, its simplicity, its low cost and its excellent environmental credentials.

Production of ultrafine particles with nanometer size distribution via a bubble film bursting method

Producing particles smaller than 50 nm continues to be a challenge for commonly used atomization techniques. In the present study, an atomization method based on bubble film bursting was proposed to generate ultrafine nanoparticles. The atomization solution added with surfactant was converted to big bubble with thin film, and three needles were employed to puncture the bubbles to produce small droplets. Droplets formed ultrafine nanoparticles after being dried by a diffusion dryer. The results showed that the median diameter of particles generated by bubble film bursting could be as low as 30 nm. The thinness of the bubble film played a significant role in producing small droplets. Additionally, the size distribution of particles was influenced by the NaCl concentration and the distance of the needle to orifice, as they altered the thickness of the bubbles. The bubble film bursting atomization method offers the advantage of producing ultrafine particles and holds potential for application in various fields.

Novel Synthesis of Nanocalcite from Phosphogypsum and Cesium Carbonate: Control and Optimization of Particle Size

This study investigates a controlled synthesis and particle size optimization of nanocalcite particles using phosphogypsum, a waste byproduct from the phosphate fertilizer industry, and cesium carbonate (Cs2CO3), a common carbonate source. The effects of synthesis parameters, including temperature and pH, on the size, morphology, and crystallinity of the synthesized nanocalcite particles were systematically examined. The optimized synthesis conditions for obtaining nanocalcite particles with desired properties are discussed. The synthesized nanocalcite particles were characterized using various techniques, such as XRD, FTIR, and SEM, to analyze their crystal structure, morphology, and elemental composition. Particle sizes were determined using the Debye–Scherrer method, and accordingly, nanometric sizes were achieved. The potential applications of the synthesized nanocalcite particles in cementitious materials, agriculture, and drug delivery are highlighted. This research provides valuable insights into the sustainable synthesis and size optimization of nanocalcite particles from phosphogypsum and Cs2CO3 at a controlled temperature and pH.

Ultrasound-Assisted Nanoemulsion Loaded with Optimized Antibacterial Essential Oil Blend: A New Approach against Escherichia coli, Staphylococcus aureus, and Salmonella Enteritidis in Trout (Oncorhynchus mykiss) Fillets.

This study aimed to obtain and characterize an oil-in-water nanoemulsion (NE) loaded with an in vitro optimized bactericidal essential oil blend of 50% oregano, 40% thyme, and 10% lemongrass and to evaluate its potential at three different concentrations (0.5%, 1%, and 2%) in the inactivation of Escherichia coli, Staphylococcus aureus, and Salmonella enterica serotype Enteritidis inoculated in rainbow trout fillets stored at 4 °C for 9 days. Regarding the NE, the nanometric size (<100 nm) with low polydispersion (0.17 ± 0.02) was successfully obtained through ultrasound at 2.09 W/cm2. Considering the three concentrations used, S. Enteritidis was the most susceptible. On the other hand, comparing the concentrations used, the NE at 2% showed better activity, reducing S. Enteritidis, E. coli, and S. aureus by 0.33, 0.20, and 0.73 log CFU/g, respectively, in the trout fillets. Thus, this data indicates that this is a promising eco-friendly alternative to produce safe fish for consumption and reduce public health risks.

INFLUENCE OF CELLULOSE NANOCRYSTALS ON POLYVINYL(PYRROLIDONE) GRAPHITE COMPOSITES

In this work, composites with poly vinyl(pyrrolidone), PVP, and graphite reinforced with cellulose nanocrystals, CNCs, were made. The CNCs had a nanometric size, with a hydrodynamic radius of 52 nm. FTIR analysis confirmed the presence of the characteristic functional groups of cellulose nanocrystals in the spectrum of pure CNCs. The PVP-graphite-CNC composites showed the characteristic peaks of PVP and graphite on the FTIR spectra, without the characteristic peaks of CNCs, which is explained by the incorporation of a small quantity of CNCs into the composites. However, the presence of CNCs increased the storage modulus of the composites by 70%, compared to the blank sample. The composites showed a glass transition temperature, attributed to PVP, and a tendency to increase with increasing CNC content; the highest CNC content caused a complex behaviour of glass transition temperature. To conclude, the addition of CNCs enhanced the mechanical properties of the composites.

Tracking nuclear motion in single-molecule magnets using femtosecond X-ray absorption spectroscopy

The development of new data storage solutions is crucial for emerging digital technologies. Recently, all-optical magnetic switching has been achieved in dielectrics, proving to be faster than traditional methods. Despite this, single-molecule magnets (SMMs), which are an important class of magnetic materials due to their nanometre size, remain underexplored for ultrafast photomagnetic switching. Herein, we report femtosecond time-resolved K-edge X-ray absorption spectroscopy (TR-XAS) on a Mn(III)-based trinuclear SMM. Exploiting the elemental specificity of XAS, we directly track nuclear dynamics around the metal ions and show that the ultrafast dynamics upon excitation of a crystal-field transition are dominated by a magnetically active Jahn-Teller mode. Our results, supported by simulations, reveal minute bond length changes from 0.01 to 0.05 Å demonstrating the sensitivity of the method. These geometrical changes are discussed in terms of magneto-structural relationships and consequently our results illustrate the importance of TR-XAS for the emerging area of ultrafast molecular magnetism.

The Role of Life Stages in the Sensitivity of Hediste diversicolor to Nanoplastics: A Case Study with Poly(Methyl)Methacrylate (PMMA).

The presence of plastic particles in oceans has been recognized as a major environmental concern. The decrease in particle size increases their ability to directly interact with biota, with particles in the nanometer size range (nanoplastics-NPs) displaying a higher ability to penetrate biological membranes, which increases with the decrease in particle size. This study aimed to evaluate the role of life stages in the effects of poly(methyl)methacrylate (PMMA) NPs on the polychaete Hediste diversicolor, a key species in the marine food web and nutrient cycle. Thus, behavioral (burrowing activity in clean and spiked sediment) and biochemical endpoints (neurotransmission, energy reserves, antioxidant defenses, and oxidative damage) were assessed in juvenile and adult organisms after 10 days of exposure to spiked sediment (between 0.5 and 128 mg PMMA NPs/Kg sediment). Overall, the results show that H. diversicolor is sensitive to the presence of PMMA NPs. In juveniles, exposed organisms took longer to burrow in sediment, with significant differences from the controls being observed at all tested concentrations when the test was performed with clean sediment, whereas in PMMA NP-spiked sediment, effects were only found at the concentrations 8, 32, and 128 mg PMMA NPs/Kg sediment. Adults displayed lower sensitivity, with differences to controls being found, for both sediment types, at 8, 32, and 128 mg PMMA NPs/Kg sediment. In terms of Acetylcholinesterase, used as a marker of effects on neurotransmission, juveniles and adults displayed opposite trends, with exposed juveniles displaying increased activity (suggesting apoptosis), whereas in adults, overall decreased activity was found. Energy-related parameters revealed a generally similar pattern (increase in exposed organisms) and higher sensitivity in juveniles (significant effects even at the lower concentrations). NPs also demonstrated the ability to increase antioxidant defenses (higher in juveniles), with oxidative damage only being found in terms of protein carbonylation (all tested NPs conditions) in juveniles. Overall, the data reveal the potential of PMMA NPs to affect behavior and induce toxic effects in H. diversicolor, with greater effects in juveniles.

Self-Aggregation, Enhanced Guest-Binding Behavior, and Anion-Induced Agglutination of Cyclophane Dimers Linked with Florescent Perylene Diimide.

Cationic, anionic, and nonionic cyclophane dimers, 1a, 1b, and 1c, covalently linked with fluorescent perylene diimide were synthesized, respectively, as a host for aggregation-induced multivalent effects on guest-binding. These PDI-linked cyclophane dimers 1a and 1b, especially 1c, formed self-aggregates in H2O-rich solvents through π-stacking interactions. Critical aggregation concentrations of 1a, 1b, and 1c in H2O were 4.0 × 10-6, 4.0 × 10-6, and less than 0.1 × 10-6 M, respectively. The self-aggregates of the PDI-linked cyclophane dimers in H2O were several hundred nanometers in size by DLS and TEM measurements. In an aggregated state, 1a exhibited guest-binding abilities toward hydrophobic guests, such as 6-p-toluidinonaphthalene-2-sulfonate and 6-anilino-naphthalene-2-sulfonate. Moreover, anion-induced agglutination of 1a was observed upon the addition of phosphate ions, and its effectiveness was as follows: ATP > ADP > H2P2O72- > AMP ≈ PO43- > HPO42- > H2PO4-. The contribution of the adenine base of the nucleotides as a guest moiety used for effective agglutination was confirmed by 1H NMR spectroscopy.

Crystal structures of two new high-pressure oxynitrides with composition SnGe4N4O4, from single-crystal electron diffraction.

SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large-volume press. Powder X-ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X-ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three-dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite-type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite-type SnGe4N4O4. The structure of this polymorph was solved as well using ADT.

Hydrothermal Synthesis of Tartaric Acid Functionalized Amino Acid CQD for Sensing of Hg2+ and Fe3+ Ions in Aqueous Medium

AbstractCarbon quantum dots (CQDs) are a type of carbon‐based nanoparticles that are typically smaller than 10 nanometres in size. In this study, L‐tryptophan‐mediated CQDs were synthesized using the hydrothermal carbonization (HTC) technique, which is known for its non‐toxic, environmentally friendly, and cost‐effective nature. The synthesized carbon quntum dot was successfully characterized. The HR‐TEM analysis clearly revealed the formation of specific aggregates with a size distribution ranging from 3.0 to 5.1 nm. These L‐tryptophan‐mediated CQDs exhibited remarkable emission behaviour, displaying strong and stable blue fluorescence. Moreover, they were utilized as a sensor for the sensitive detection of Fe3+ and Hg2+ ions in an aqueous solution, employing a fluorescence quenching mechanism. The limit of detection for Fe3+ sensing was determined to be 1.2×10−5 M, while for Hg2+ sensing, it was found to be 1.9×10−5 M. The sensing of Fe3+ and Hg2+ ions was also confirmed through visual eye detection, as a significant color change of the CQDs was observed. Additionally, a competitive study was conducted to verify the selectivity of the L‐tryptophan‐mediated CQDs towards Fe3+ and Hg2+ metal ions.

Variation of (001) surface structures of strontium titanate single crystals caused by flash event under direct/alternative current electric fields

Flash events, which are electric power spikes occurring under an electric field and temperature above the threshold, can significantly accelerate mass diffusion over short periods of time. This study investigated the surface structure of the (001) surface of strontium titanate single-crystal treated by flash events caused by direct current (DC) and alternating current (AC) electric fields from a viewpoint of surface-related mass diffusion. The surface structuring caused by flash events was significantly different among DC and AC electric fields. The DC-flash event destabilized surface steps, causing them to wander and form surface mounds with a height of several tens of nanometers. In addition, numerous two-dimensional (2D) nuclei with a size of several nanometers are formed on the terraces. In contrast, the AC-flash event stabilized surface steps without the formation of surface mounds, causing them nearly straight with uniform terrace width at approximately 500 nm. 2D nuclei with a size of a few 10 nm were formed at the step edges with round shapes. Both methods were confirmed as evidenced by the formation of two-dimensional nuclei on the surface after the flash events, to enhance surface-related mass diffusion.

Improving the emission properties of graphene–carbon nanotube hybrid nanostructures through functionalization with BaO nanoparticles and laser treatment

This paper presents the manufacturing technology of hybrid nanostructures based on a buffer layer of reduced graphene oxide (rGO) flakes with vertical single-walled carbon nanotubes (SWCNTs) and their bundles functionalized with BaO nanoparticles. Using density functional theory (DFT) calculations, supercells of rGO/SWCNT/BaO films were constructed and the patterns of the electron work function were revealed. It has been demonstrated that the electron work function is influenced by both the mass fraction of BaO nanoparticles and the inter-tube distance. Branched carbon nanostructure was formed using a pulsed laser irradiation. Fragmentation of BaO nanoparticles on the carbon surface was achieved. It was shown that after laser treatment, Ba(NO3)2 particles up to 200 nm in size were fragmented into smaller BaO nanoparticles with sizes of a few nanometers, covering the nanotubes. The field emission current–voltage characteristics (CVCs) were measured and showed a 42-fold increase in emission current compared to the nanostructure without BaO functionalization and laser treatment. BaO-functionalized hybrid carbon nanostructures are predicted to be efficient field cathodes, with a current density of at least 2 A/cm2, for use in X-ray tubes, field emission displays, and vacuum microwave devices.

Revealing intermetallic strengthening in bainitic steel designed for nickel aluminide formation

BainNiAlCu steel was designed to achieve a cementite-free bainitic structure and susceptibility to the formation of intermetallic phases at elevated temperatures. Based on Transmission Electron Microscopy (TEM) observations, the intermetallic strengthening occurring in the bainitic ferrite matrix was revealed. The B2-ordered phase are rich in Ni, Al, and Cu, which indicates the growth of NiAl/Cu co-precipitates. The intermetallic phase was characterized by a spherical morphology and nanometer size. The micro-segregation of Ni, Al and Cu was observed at the boundaries of cementite particles and the bainitic matrix. The redistribution of atoms during the growth of carbides forms a heterogeneous nickel aluminide nucleation site. Intermetallic strengthening is a promising strategy for controlling the thermal stability of bainitic structures. The results of this research constitute fundamental knowledge regarding the design of ultra-fine, cementite-free bainitic steels subjected to intermetallic strengthening.

Simultaneous Detection of Carbon Quantum Dots as Tracers for Interwell Connectivity Evaluation in a Pattern with Two Injection Wells.

This study aimed to develop and implement a nanotechnology-based alternative to traditional tracers used in the oil and gas industry for assessing interwell connectivity. A simple and rapid hydrothermal protocol for synthesizing carbon quantum dots (CQDs) using agroindustry waste was implemented. Three commercial CQDs were employed (CQDblue, CQDgreen, and CQDred); the fourth was synthesized from orange peel (CQDop). The CQDs from waste and other commercials with spherical morphology, nanometric sizes less than 11 nm in diameter, and surface roughness less than 3.1 nm were used. These tracers demonstrated high colloidal stability with a negative zeta potential, containing carbonyl-type chemical groups and unsaturations in aromatic structures that influenced their optical behavior. All materials presented high colloidal stability with negative values of charge z potential between -17.8 and -49.1. Additionally, individual quantification of these tracers is feasible even in scenarios where multiple CQDs are present in the effluent with a maximum percentage of interference of 15.5% for CQDop in the presence of the other three nanotracers. The CQDs were injected into the field once the technology was insured under laboratory conditions. Monitoring the effluents allowed the determination of connectivity for five first-line producer wells. This study enables the application of CQDs in the industry, particularly in fields where the arrangement of injector and producer wells is intricate, requiring the use of multiple tracers for a comprehensive description of the system.

Application of Calcium Carbonate in the Pharmaceutical Removal Process

One way to reduce the negative impact of human activity on the natural environment is to use natural, easily available and relatively cheap to produce compounds in industrial processes. One such compound is naturally occurring calcium carbonate (CaCO3). This compound has adsorption properties so that it can be an alternative to commonly used adsorbents. The aim of this work is to determine the possibility of using CaCO3 to remove pharmaceutical substances such as sulfadiazine and tetracycline from water. The CaCO3 used in this work was synthesised using our own method, which allows the production of CaCO3 particles with nanometric size. In the conducted research, calcium carbonate was used in the form of a suspension in purified solutions and as an inorganic filling of the developed membranes. The mass of pharmaceutical substances removed from their aqueous solutions was determined in the tests carried out. Based on the results obtained, it can be concluded that CaCO3 has the ability to adsorb both tetracycline and sulfadiazine. In suspension tests, the mass of the removed substances per unit mass of adsorbent was 1.52 mg/g and 6.85 mg/g, respectively. In turn, in the case of the integrated process using the developed membranes, the mass of the removed substances per unit mass of adsorbent was 109 mg/g and 97 mg/g.

Superoxide Dismutase-Mimetic Polyphenol-Based Carbon Dots for Multimodal Bioimaging and Treatment of Atopic Dermatitis.

Polyphenols have been investigated for their potential to mitigate inflammation in the context of atopic dermatitis (AD). In this study, epigallocatechin-3-gallate (EGCG)-based carbon dots (EGCG@CDs) were developed to enhance transdermal penetration, reduce inflammation, recapitulate superoxide dismutase (SOD) activity, and provide antimicrobial effects for AD treatment. The water-soluble EGCG@CDs in a few nanometers size exhibit a negative zeta potential, making them suitable for effective transdermal penetration. The fluorescence properties, including an upconversion effect, make EGCG@CDs suitable imaging probes for both in vitro and in vivo applications. By mimicking the SOD enzyme, EGCG@CDs scavenge reactive oxygen species (ROS) and actively produce hydrogen peroxide through a highly catalytic capability toward the oxygen reduction reaction, resulting in the inhibition of bacterial growth. The enhanced antioxidant properties, high charge mobility, and various functional groups of EGCG@CDs prove effective in reducing intracellular ROS in an in vitro AD model. In the mouse AD model, EGCG@CDs incorporated into a hydrogel actively penetrated the epidermal layer, leading to ROS scavenging, reduced mast cell activation, and histological recovery of skin barriers. This research represents the versatile potential of EGCG@CDs in addressing AD and advancing tissue engineering.

A sterilizable platform based on crosslinked xanthan gum for controlled-release of polymeric micelles: Ocular application for the delivery of neuroprotective compounds to the posterior eye segment

TPGS (D-α-tocopheryl polyethylene glycol 1000 succinate) polymeric micelles show interesting properties for ocular administration thanks to their solubilization capability, nanometric size and tissue penetration ability. However, micelles formulations are generally characterized by low viscosity, poor adhesion and very short retention time at the administration site. Therefore, the idea behind this work is the preparation and characterization of a crosslinked film based on xanthan gum that contains TPGS micelles and is capable of controlling their release. The system was loaded with melatonin and cyclosporin A, neuroprotective compounds to be delivered to the posterior eye segment. Citric acid and heating at different times and temperatures were exploited as crosslinking approach, giving the possibility to tune swelling, micelles release and drug release. The biocompatibility of the platform was confirmed by HET-CAM assay. Ex vivo studies on isolated porcine ocular tissues, conducted using Franz cells and two-photon microscopy, demonstrated the potential of the xanthan gum-based platform and enlightened micelles penetration mechanism. Finally, the sterilization step was approached, and a process to simultaneously crosslink and sterilize the platform was developed.