Search Results (89)

We present three dimensional particle-in-cell simulations of current-voltage characteristics of the hemispherical Langmuir probe (LAP), onboard the China Seismo-Electromagnetic Satellite (CSES). Using realistic plasma parameters and background magnetic fields obtained from the International Reference Ionosphere (IRI) and International Geomagnetic Reference Field (IGRF) models, we simulate probe–plasma interactions at three locations: the equatorial region and two magnetically conjugate mid-latitude sites: Millstone Hill (Northern Hemisphere) and Rothera (Southern Hemisphere). The simulations, performed using the PTetra PIC code, incorporate realistic LAP geometry and spacecraft motion in the ionospheric plasma. Simulated current voltage characteristics or I–V curves are compared against in-situ LAP measurements from CSES Orbit-026610, with Pearson’s correlation coefficients used to assess agreement. Our findings indicate how plasma temperature, density, and magnetization affect sheath structure and probe floating potential. The study highlights the significance of kinetic modeling in enhancing diagnostic accuracy, particularly in variable sheath regimes where classic analytical models such as the Orbital-Motion-Limited (OML) theory may be inadequate. Full article

Extracellular vesicles (EVs) are nanoscale particles released by cells and are significant components in intercellular communication. Their ability to reflect the molecular state of parental cells and their presence in body fluids make them increasingly recognized as promising non-invasive biomarkers for different pathological conditions. However, the existence of different EV populations and frequent co-isolation of contaminants present challenges for EV purification and downstream analyses. In this study, we used three novel nanobodies (VHH) for selective isolation of EVs from human plasma. Nanobodies were obtained by direct panning on EVs. All examined nanobodies have excellent physicochemical properties resulting in excellent expression and solubility. The three nanobodies being studied—NA8, ND10₁, and ND10₂—share a conserved VHH scaffold but exhibit different loop architectures. The Biopython ProtParam module was used for calculation of VHH physicochemical properties, while sequence alignments for evaluation of variations were performed with the Biopython pairwise2 module. In addition, structural modeling of nanobodies with AlphaFold revealed notable differences in CDR3 conformations. VHH were produced in E. coli, and upon immobilization onto a solid carrier, they were used for immunoaffinity-based capture of EVs from human plasma. Combined characterization of isolated EVs supports efficient application of an immunoaffinity-based system based on such nanobodies for the isolation of EVs from human plasma to be used for downstream analyses. Full article

In the environment, plastic waste degrades into small particles known as microplastics and nanoplastics (MNPLs), depending on their size. Given the potential harmful effects associated with MNPL exposure, it is crucial to develop environmentally representative particles for hazard assessment. These so-called true-to-life MNPLs are generated through in-house degradation of real-world plastic products. In this study, we produced titanium-doped nanoplastics (NPLs) from opaque polyethylene terephthalate (PET) milk bottles, which contain titanium dioxide as a filler. The resulting PET(Ti)-NPLs were thoroughly characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), mass spectrometry (MS), dynamic light scattering (DLS), ζ-potential measurements, transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. Human-derived THP-1 monocytes were employed to investigate particle uptake kinetics, dosimetry, and genotoxicity. A combination of flow cytometry and inductively coupled plasma mass spectrometry (ICP-MS) enabled the quantification of internalized particles, while the comet assay assessed DNA damage. The results revealed dose- and time-dependent effects of PET(Ti)-NPLs on THP-1 cells, particularly in terms of internalization. Titanium doping facilitated detection and influenced genotoxic outcomes. This study demonstrates the relevance of using environmentally representative nanoplastic models for evaluating human health risks and underscores the importance of further mechanistic research. Full article

Background/Objectives: Boron neutron capture therapy (BNCT) is a promising, less-invasive anticancer treatment. However, the development of effective boron-based agents (BNCT probes) remains a critical and challenging issue. Previously, we developed a styrene–maleic acid (SMA) copolymer conjugated with glucosamine, encapsulating boronic acid, which exhibited tumor-targeted distribution via the enhanced permeability and retention (EPR) effect. Building upon this approach, in this study, we designed and synthesized a series of SMA-based polymeric probes for BNCT and evaluated their biological activities, with a particular focus on tumor-targeting properties. Methods: Two SMA-based BNCT nanoprobes, SMA–glucosamine conjugated Borax (SG@B) and SMA-conjugated aminophenylboronic acid encapsulating tavaborole (S-APB@TB), were designed and synthesized. The boron content in the conjugates was quantified using inductively coupled plasma mass spectrometry (ICP-MS), while particle sizes were measured via dynamic light scattering (DLS). In vitro cytotoxicity was assessed using the MTT assay in mouse colon cancer C26 cells. The tissue distribution of the conjugates was analyzed in a mouse sarcoma S180 solid tumor model using ICP-MS. Results: Both SG@B and S-APB@TB formed nanoformulations with average particle sizes of 137 nm and 99 nm, respectively. The boron content of SG@B was 2%, whereas S-APB@TB exhibited a significantly higher boron content of 14.4%. Both conjugates demonstrated dose-dependent cytotoxicity against C26 cells, even in the absence of neutron irradiation. Notably, tissue distribution analysis following intravenous injection revealed higher boron concentrations in plasma and tumor tissues compared to most normal tissues, with S-APB@TB showing particularly favorable tumor accumulation. Conclusions: These findings highlight the tumor-targeting potential of SMA-based BNCT nanoprobes. Further investigations are warranted to advance their clinical development as BNCT agents. Full article

Reconstituted high-density lipoprotein nanoparticles (NPs), which mimic the structure and function of endogenous human plasma HDL, hold promise as a robust drug delivery system. These nanoparticles, when loaded with appropriate agents, serve as powerful tools for targeted drug delivery. The fundamental challenge lies in controlling and estimating the actual drug load and the efficiency of drug release at the target. In this report, we present a novel approach based on enhanced Förster Resonance Energy Transfer (FRET) to assess particle load and monitor payload release. The NPs are labeled with donor molecules embedded in the lipid phase, while the spherical core volume is filled with acceptor molecules. Highly enhanced FRET efficiency to multiple acceptors in the NP core has been observed at distances significantly larger than the characteristic Förster distance (R₀). To confirm that the observed changes in donor and acceptor emissions are a result of FRET, we developed a theoretical model for nonradiative energy transfer from a single donor to multiple acceptors enclosed in a spherical core volume. The load-dependent shortening of the fluorescence lifetime of the donor correlated with the presence of a negative component in the intensity decay of the acceptor clearly demonstrates that FRET can occur at a large distance comparable to the nanoparticle size (over 100 Å). Comparison of theoretical simulations with the measured intensity decays of the donor and acceptor fluorophores constitute a new method for evaluating particle load. The observed FRET efficiency depends on the number of acceptors in the core, providing a simple way to estimate the nanoparticle load efficiency. Particle disintegration and load release result in a distinct change in donor and acceptor emissions. This approach constitutes a novel strategy for assessing NP core load, monitoring NP integrity, and evaluating payload release efficiency to target cells. Significants: In the last decade, nanoparticles have emerged as a promising strategy for targeted drug delivery, with applications ranging from cancer therapy to ocular neurodegenerative disease treatments. Despite their potential, a significant issue has been the real-time monitoring of these drug delivery vehicles within biological systems. Effective strategies for monitoring NP payload loading, NP integrity, and payload release are needed to assess the quality of new drug delivery systems. In our study, we have found that FRET-enabled NPs function as an improved method for monitoring these aspects currently missing from current drug delivery efforts. Full article

Objectives: Thermo-gelling hydrophilic polymers like PLGA–PEG–PLGA are known as injectable sustained-release depots for biologics, but they face challenges due to the occurrence of severe burst release. This study aimed to develop a strategy to avoid the initial burst release by pre-encapsulating proteins in polysaccharide microparticles through an aqueous–aqueous emulsion mechanism, thereby enhancing therapeutic retention and linear release kinetics. Methods: Five model proteins (G-CSF, GM-CSF, IGF-1, FVIII, BSA) were encapsulated in dextran microparticles, using an organic solvent-free aqueous–aqueous emulsion method. These particles were dispersed in a 23% (w/w) PLGA–PEG–PLGA solution and injected into a 37 °C release buffer to form a gel depot. The in vitro release profiles were quantified using ELISA and MicroBCA assays over 9–42 days. The bioactivity of the proteins was validated using cell proliferation assays (NFS-60, TF-1, MCF-7) and chromogenic kits. The in vivo pharmacokinetics of the FVIII-loaded formulations were evaluated in Sprague–Dawley rats (n = 5/group) over 28 days. Results: Protein-loaded dextran particles retained their structural integrity within the hydrogel and exhibited minimal burst release (≤5% within 30 min vs. >25% for free proteins). Sustained near-linear release profiles were observed for all the proteins, with complete release by day 9 (G-CSF, GM-CSF, BSA) or day 42 (FVIII). Rats administered with the thermal gel with FVIII–dextran particles showed a significantly lower peak plasma concentration (C_max: 88.25 ± 30.21 vs. 132.63 ± 66.67 ng/mL) and prolonged therapeutic coverage (>18 days vs. 15 days) compared to those administered with the thermal gel with the FVIII solution. The bioactivity of the released proteins remained at ≥90% of the native forms. Conclusions: Pre-encapsulation in dextran microparticles effectively mitigates burst release from thermosensitive hydrogels, while preserving protein functionality. Full article

This work studied the pre-plasma that builds up in interactions of focused high-power PW-class lasers with solid targets at the target surface facing the laser beam, and its impact on the global laser absorption efficiency as well as on the spectral cut-off energy of laser-generated proton beams. Our practical heuristic estimates were derived from the example of the VEGA-3 laser at CLPU. Our modeling results for the pre-plasma expansion due to the laser pedestal of VEGA-3 were benchmarked by hydrodynamic simulations, revealing good agreement for the evolution before the arrival of the main Gaussian laser intensity peak. Our detailed numerical two-dimensional Particle-in-Cell simulations showed the impact of different pre-plasma scale lengths on the absorption efficiency of laser energy into electrons, relevant for the seeding of other types of radiation. It was shown that the absorption can increase manyfold when increasing the pre-plasma scale length. This effect can be beneficial for the spectral cut-off energy of accelerated protons, where a trade-off between absorption and electron dynamics yields an optimum pre-plasma scale length. The findings can be applied to other PW-class laser facilities. Full article

Food-grade titanium dioxide (E171) is widely used in food, feed, and pharmaceuticals for its opacifying and coloring properties. This study investigates the formation of reactive oxygen species (ROS) and the aggregation behavior of E171 using the TNO Gastrointestinal (GI) model, which simulates the stomach and small intestine. E171 was characterized using multiple techniques, including electron spin resonance spectroscopy, single-particle inductively coupled plasma–mass spectrometry, transmission electron microscopy, and dynamic light scattering. In an aqueous dispersion (E171-aq), E171 displayed a median particle size of 79 nm, with 73–75% of particles in the nano-size range (<100 nm), and significantly increased ROS production at concentrations of 0.22 and 20 mg/mL. In contrast, when E171 was mixed with yogurt (E171-yog), the particle size increased to 330 nm, with only 20% of nanoparticles, and ROS production was inhibited entirely. After GI digestion, the size of dE171-aq increased to 330 nm, while dE171-yog decreased to 290 nm, with both conditions showing a strongly reduced nanoparticle fraction. ROS formation was inhibited post-digestion in this cell-free environment, likely due to increased particle aggregation and protein corona formation. These findings highlight the innate potential of E171 to induce ROS and the need to consider GI digestion and food matrices in the hazard identification/characterization and risk assessment of E171. Full article

This paper presents the initial results of the synthesis of β-Ga₂O₃ luminescent ceramics via plasma gas-thermal spraying synthesis, where low-temperature plasma of an argon and nitrogen mixture was employed. A direct current electric arc generator of high-enthalpy plasma jet with a self-aligning arc length and an expanding channel of an output electrode served as a plasma source. The feedstock material consisted of a polydisperse powder of monocrystalline β-Ga₂O₃ with particle sizes ranging from 5 to 50 μm. The study presents the results of both theoretical and experimental studies on the heating rate and average temperature of gallium oxide particles in a plasma jet. The results of computational modelling of the synthesis process of β-Ga₂O₃ via plasma gas-thermal spraying are shown. The obtained ceramic samples were characterized using scanning electron microscopy and X-ray diffraction analysis. Our results indicate that the synthesis process yielded ceramics with a layered texture. The stoichiometric composition of ceramics exhibited a shift towards gallium-rich content. X-ray diffraction data demonstrated a reduction in the lattice parameters and unit cell volume of β-Ga₂O₃ ceramic structure. Radioluminescence spectra of β-Ga₂O₃ ceramics revealed an intensive emission band with a maximum at ~360 nm and non-exponential decay. The synthesized β-Ga₂O₃ ceramics possess potential applications in scintillation detectors. Full article

This study explores the fabrication of tannic acid-crosslinked gelatin nanofibers via electrospinning, followed by helium and nitrogen plasma treatment to enhance their biofunctionality, which was assessed using fibroblast cells. The nanofibers were characterized using scanning electron microscopy, atomic force microscopy, attenuated total reflection Fourier transform infrared spectroscopy, X-ray diffraction, and water contact angle measurements before and after treatment. Helium and nitrogen gas plasma were employed to modify the nanofiber surfaces. Results indicated that helium and nitrogen plasma treatment significantly increased the hydrophilicity and biofunctionality of the nanofibers by 5.1° ± 0.6 and 15.6° ± 2.2, respectively, making them more suitable for human skin fibroblast applications. To investigate the impact of plasma treatment on gelatin, we employed a computational model using density functional theory with the B3LYP/6-31+G(d) method. This model represented gelatin as an amino acid chain composed of glycine, hydroxyproline, and proline, interacting with plasma particles. Vibrational analysis of these systems was used to interpret the vibrational spectra of untreated and plasma-treated gelatin. To further correlate with experimental findings, molecular dynamics simulations were performed on a system of three interacting gelatin chains. These simulations explored changes in amino acid bonding. The computational results align with experimental observations. Comprehensive analyses confirmed that these treatments improved hydrophilicity and biofunctionality, supporting the use of plasma-treated gelatin nanofibers in skin tissue engineering applications. Gelatin’s natural biopolymer properties and the versatility of plasma surface modification techniques underscore its potential in regenerating cartilage, skin, circulatory tissues, and hamstrings. Full article

Ambipolar plasma thrusters are an appealing technology due to multiple system-related advantages, including propellant flexibility and the absence of electrodes or neutralizer. Understanding the plasma generation and acceleration mechanisms is key to improving the performance and capabilities of these thrusters. However, the source and plume regions inside are often simulated separately, and no self-consistent strategy exists which can couple these different simulations together. This paper introduces the MUlti-regime Plasma Equilibrium Transport Solver (MUPETS), a self-consistent coupled model integrating a fluid solver for the plasma dynamics in the source, which are collision-driven, with a kinetic Particle-In-Cell (PIC) code for the plasma dynamics in the magnetic nozzle, which involve expansion across a diverging magnetic field. The methodology begins by solving the plasma source with the classical Bohm condition at the thruster’s throat. The resulting plasma profiles (density, temperature, speed) are input into the PIC code for the magnetic nozzle. The PIC code calculates the plasma plume expansion and determines the electric field at the thruster’s throat. This electric field is then used as a boundary condition in the fluid code, where it replaces the Bohm assumption, and the fluid simulation is repeated. This iterative process continues until convergence. In comparing the MUPETS results with those for an experimental thruster, the plasma densities at the thruster’s throat differed by less than 2–5% between the fluid and PIC regions. The thrust predictions agreed with the experimental trend, and were kept well within the measurement’s uncertainty band. These results validate the effectiveness of the coupling strategy for enhancing plasma thruster simulation accuracy. Full article

This work explores microcombustion technologies enhanced by plasma-assisted combustion, focusing on a novel simulation model for a Y-shaped device with a non-premixed hydrogen-air mixture. The simulation integrates the ZDPlasKin toolbox to determine plasma-produced species concentrations to Particle-In-Cell with Monte Carlo Collision analysis for momentum and power density effects. The study details an FE-DBD plasma actuator operating under a sinusoidal voltage from 150 to 325 V peak-to-peak and a 162.5 V DC bias. At potentials below 250 V, no hydrogen dissociation occurs. The equivalence ratio fitting curve for radical species is incorporated into the plasma domain, ensuring local composition accuracy. Among the main radical species produced, H reaches a maximum mass fraction of 8% and OH reaches 1%. For an equivalence ratio of 0.5, the maximum temperature reached 2238 K due to kinetic and joule heating contributions. With plasma actuation with radicals in play, the temperature increased to 2832 K, and with complete plasma actuation, it further rose to 2918.45 K. Without plasma actuation, the temperature remained at 300 K, reflecting ambient conditions and no combustion phenomena. At lower equivalence ratios, temperatures in the plasma area consistently remained around 2900 K. With reduced thermal power, the flame region decreased, and at Φ = 0.1, the hot region was confined primarily to the plasma area, indicating a potential blow-off limit. The model aligns with experimental data and introduces relevant functionalities for modeling plasma interactions within microcombustors, providing a foundation for future validation and numerical models in plasma-assisted microcombustion applications. Full article

Early diagnosis, intervention, and therapeutic advancements have extended the lives of breast cancer patients; however, even with molecularly targeted therapies, many patients eventually progress to metastatic cancer. Recent data suggest that residual breast cancer cells often reside in the lymphatic system before rapidly spreading through the bloodstream. To address this challenge, an effective drug combination composed of gemcitabine (G) and paclitaxel (T) is administered intravenously in sequence at the metastatic stage, but intravenous GT infusion may limit lymphatic GT drug accessibility and asynchronous drug exposure in cancer cells within the lymph. To determine whether co-localization of intracellular gemcitabine and paclitaxel (referred to as GT) could overcome these limitations and enhance the efficacy of GT, we have evaluated a previously reported GT drug-combination formulated in nanoparticle (referred to as GT-in-DcNP) evaluated in an orthotopic breast tumor model. Previously, with indocyanine green-labeled nanoparticles, we reported that GT-in-DcNP particles after subcutaneous dosing were taken up rapidly and preferentially into the lymph instead of blood vessels. The pharmacokinetic study showed enhanced co-localization of GT within the tumors and likely through lymphatic access, before drug apparency in the plasma leading to apparent long-acting plasma time-course. The mechanisms may be related to significantly greater inhibitions of tumor growth—by 100 to 140 times—in both sub-iliac and axillary regions compared to the equivalent dosing with free-and-soluble GT formulation. Furthermore, GT-in-DcNP exhibited dose-dependent effects with significant tumor regression. In contrast, even at the highest dose of free GT combination, only a modest tumor growth reduction was notable. Preliminary studies with MDA-231-HM human breast cancer in an orthotopic xenograft model indicated that GT-in-DcNP may be effective in suppressing human breast tumor growth. Taken together, the synchronized delivery of GT-in-DcNP to mammary tumors through the lymphatic system offers enhanced cellular retention and greater efficacy. Full article

The breakdown of CF₃I gas at low pressure is of significant importance for applications in fields such as aerospace and microelectronics. However, the DC low-pressure breakdown characteristics of CF₃I remain underexplored. In this work, we utilize a one-dimensional implicit particle-in-cell/Monte Carlo collision (PIC/MCC) algorithm to investigate the complete DC breakdown process of low-pressure CF₃I. Our model accounts for ion–molecule collisions, recombination reactions, and external circuit influences. The breakdown process is delineated into three stages: before breakdown, breakdown, and after breakdown. In the before-breakdown stage, both the density and energy of particles are low. In the breakdown stage, the rapid increase in electron density and energy accelerates ionization reactions, leading to successful breakdown. The circuit behavior transitions from capacitive to resistive, sharing voltage with the external resistance. In the after-breakdown stage, continued positive ion growth leads to the formation of a thin anode sheath and a negative plasma potential. Energy production, including heating power and secondary electron emission (SEE) power, balances with energy loss through collision and boundary absorption. Specifically, 62% of the total heating power comes from positive ions, 1.5% from negative ions, and approximately 85% of electron energy is lost via boundary absorption. Finally, we compare the Paschen curves of CF₃I with those of SF₆, providing insights that are beneficial for the application of CF₃I as an SF₆ alternative. Full article

PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) is an INFN project aiming at measuring, for the first time, possible variations in in-plasma $\beta$-decay lifetimes in isotopes of astrophysical interest as a function of thermodynamical conditions of the in-laboratory controlled plasma environment. Theoretical predictions indicate that the ionization state can dramatically modify the $\beta$-decay lifetime (even of several orders of magnitude). The PANDORA experimental approach consists of confining a plasma able to mimic specific stellar-like conditions and measuring the nuclear decay lifetime as a function of plasma parameters. The $\beta$-decay events will be measured by detecting the $\gamma$-ray emitted by the daughter nuclei, using an array of 12 HPGe detectors placed around the magnetic trap. In this frame, plasma parameters have to be continuously monitored online. For this purpose, an innovative, non-invasive multi-diagnostic system, including high-resolution time- and space-resolved X-ray analysis, was developed, which will work synergically with the $\gamma$-rays detection system. In this contribution, we will describe this multi-diagnostics system with a focus on spatially resolved high-resolution X-ray spectroscopy. The latter is performed by a pin-hole X-ray camera setup operating in the 0.5–20 keV energy domain. The achieved spatial and energy resolutions are 450 µm and 230 eV at 8.1 keV, respectively. An analysis algorithm was specifically developed to obtain SPhC (Single Photon-Counted) images and local plasma emission spectrum in High-Dynamic-Range (HDR) mode. Thus, investigations of image regions where the emissivity can change by even orders of magnitude are now possible. Post-processing analysis is also able to remove readout noise, which is often observable and dominant at very low exposure times (ms). Several measurements have already been used in compact magnetic plasma traps, e.g., the ATOMKI ECRIS in Debrecen and the Flexible Plasma Trap at LNS. The main outcomes will be shortly presented. The collected data allowed for a quantitative and absolute evaluation of local emissivity, the elemental analysis, and the local evaluation of plasma density and temperature. This paper also discusses the new plasma emission models, implemented on PIC-ParticleInCell codes, which were developed to obtain powerful 3D maps of the X-rays emitted by the magnetically confined plasma. These data also support the evaluation procedure of spatially resolved plasma parameters from the experimental spectra as well as, in the near future, the development of appropriate algorithms for the tomographic reconstruction of plasma parameters in the X-ray domain. The described setups also include the most recent upgrade, consisting of the use of fast X-ray shutters with special triggering systems that will be routinely implemented to perform both space- and time-resolved spectroscopy during transient, stable, and turbulent plasma regimes (in the ms timescale). Full article