Journal of Nanoparticle Research最新文献

The quasi-harmonic Debye model combined with the Density Functional Theory (DFT) is used to analyze the thermodynamic properties of vanadium silicides (VSi₂) compound utilizing the Wien2k code. The formation enthalpy calculations revealed that this compound exhibits thermodynamic stability. The obtained results reveal a consistent variation in the thermodynamic properties of VSi₂ as a function of temperature and pressure. These findings are in good agreement with the behavior commonly observed in the literature. The thermodynamic values thus predicted can be used as a guide for future research on electronic packaging applications. Various thermodynamic parameters were calculated, including the unit cell volume, bulk modulus, Debye temperature, Gibbs free energy, specific heat capacities at constant volume and constant pressure, vibrational internal energy, Helmholtz free energy, thermal expansion coefficient, and Grüneisen parameter. The results of the last property and the thermal expansion coefficient indicate a reduction in anharmonicity in VSi₂ and limited lattice expansion at low temperatures. In addition, the character of the specific heat capacity at constant volume confirms the characteristics of solids at high temperatures, and the entropy exhibits a strong positive correlation with temperature, reflecting the rise in thermal energy.

In order to deal with the high thermal decomposition temperature of molecular perovskite energetic material (H₂dabco)[NH₄(ClO4)₃] (DAP-4), DAP-4/GO composites were prepared using GO as a catalyst. These samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) to analyze morphology, structure, and thermal properties. The ignition and combustion processes were recorded using high-speed imaging, and the enthalpy of combustion was measured via oxygen bomb calorimetry. Results demonstrate that GO significantly reduces the thermal decomposition temperature of DAP-4 by 32.5 °C and decreases its activation energy by 44.1 kJ/mol. Combustion performance was markedly enhanced, combustion duration increased from 196 to 300 ms, and the enthalpy of combustion increased by 945 kJ/kg. Both DAP-4 and DAP-4/GO composites exhibited bright yellow flames. These findings confirm the effective catalytic role of GO in enhancing the thermal decomposition and combustion behavior of DAP-4.

Environmental health concerns because of nano-microplastics (NMPs) are growing, yet in vivo data in mammals remain scarce. Most analysis techniques rely on excised organs, limiting the ability to observe real-time NMP migration within living organisms. Therefore, there is an increasing need for simple, non-invasive techniques to track NMPs in vivo. In this study, we utilized near-infrared (NIR) fluorescence (NIRF), known as the second biological window in NIR (NIR-II), and applied it to in vivo optical imaging of deep tissue. NIR-II fluorescent poly(ethylene terephthalate) (PET) particles were synthesized by encapsulating the NIR-II fluorescent dye IR-1061 into PET. PET was dissolved in acetonitrile and stirred with IR-1061 under a nitrogen atmosphere for 24 h, with a dye loading of 1.56 mg/mg PET. To prevent agglomeration and control particle size (30–300 nm), an aqueous bovine serum albumin solution (0.02–50 mg/mL) was added. The mixture was then stirred in open air for 48 h to evaporate residual acetonitrile. In vivo NIRF imaging enabled real-time tracking of PET particles’ distribution over time following oral administration to mice. This method offers a promising platform for evaluating the behavior and potential toxicity of NMPs based on their size and composition.

Kremersite [(NH₄)₂FeCl₅·H₂O] is a rare and structurally unstable iron phase, scarcely described in the mineralogical literature and unexplored at the nanoscale. Here, it is reported a systematic investigation of nano-kremersite (KreNPs), obtained through a green and sustainable recovery route from akaganeite (AkaNPs) synthesis residues. This circular approach not only reduces synthetic waste but also enables access to a metastable and underexplored phase. To ensure reliable identification, KreNPs were compared with hematite, goethite, and magnetite synthesized under controlled conditions. A comprehensive characterization was carried out using SEM/TEM, XRD, FTIR, EDS, DLS, NTA, zeta potential, and TGA/DTA analyses. KreNPs exhibited well-defined prismatic morphologies, orthorhombic crystalline order, and chloride-rich composition consistent with their unit cell, distinguishing them from AkaNPs and other iron oxides. Thermal analysis further confirmed the existence of unique dehydration and transformation pathways. Structural refinement based on XRD confirmed enhanced crystallinity and reduced amorphous contribution compared to other nanoparticles. By demonstrating that a scarcely occurring mineral can be stabilized in nanoparticulate form through residue valorization, this work expands mineralogical knowledge while reinforcing principles of green chemistry. Beyond advancing mineralogical knowledge, these findings highlight the potential of sustainable synthetic strategies to access metastable phases, paving the way for future studies on their functional properties and technological applications.

Graphical Abstract

A detailed computational investigation of 55-atom Pd(_{varvec{N}})Ag(_{varvec{42-N}})Ni(_{varvec{13}}) Mackay-icosahedral nanoalloys is presented, combining Gupta-potential Basin-Hopping, spin-polarized DFT, local virial stress mapping, and finite-temperature molecular dynamics (MD). Chemical-ordering optimizations reveal that Ag preferentially occupies vertex sites while Pd populates edges and subsurfaces, yielding composition-dependent mixing energies that remain unfavorable up to (varvec{Napprox 8}) at the DFT level. Local pressure maps show anomalous surface compression and tensile subshells in Ag-rich clusters (Ni–Ag mismatch (varvec{approx 16%})) and conventional compressive-core/tensile-shell distributions in Pd-rich clusters (Ni–Pd mismatch (varvec{approx 10%})). Melting-dynamics analyses indicate sharp transitions with no pre-melting surface rearrangements. The anomalous pressure distribution in Ag-rich compositions lowers their thermal resistance, resulting in melting at significantly lower temperatures than Pd-rich clusters, which maintain conventional stress profiles and higher thermal stability. Spin-polarized DFT confirms Ni atoms carry the dominant local magnetic moments, governed by coordination rather than local stress. Alternative Bergman-shell variants were also tested, demonstrating that a 32-atom shell restores the expected compressive-core/tensile-shell stress pattern.

In the present work, we synthesized zinc-phosphate particles (Zn₃(PO₄)₂) of micro- and nanometric sizes (ZnPMCPs y ZnPNPs) through chemical reduction under acidic and alkaline conditions, aiming to obtain stable colloidal solutions either in the reaction medium or through particle suspension. In acidic media, the addition of hydrochloric acid (HCl), citric acid (AC), or ascorbic acid (AA) led to the formation of spherical structures with zeta potential superior to + 100 mV. Conversely, the use of ammonium hydroxide (NH₄OH) in alkaline conditions resulted in oval flat-shaped structures with zeta potential below − 53.9 mV, with a tendency toward agglomeration before suspension. Among the tested media, HCl proved to be the most effective for nanoparticle suspension, enabling the production of particles with average hydrodynamic diameters below 25 nm and exhibiting high colloidal stability based on their zeta potential absolute values. These findings demonstrate a simple, reproducible method for producing micro/nanoparticles with excellent colloidal stability, which can be recovered post-suspension without loss of stability. The synthesized particles have promising potential for applications in biomedical engineering and anticorrosive coatings.

Graphical abstract

Nosocomial infections pose a major global threat to patient safety, leading to longer hospital stays, increased disability and death, higher healthcare costs, and contributing to antimicrobial resistance. These infections are often linked to inadequate disinfection, invasive medical procedures, and microbial buildup on healthcare surfaces and devices. Therefore, developing new strategies to prevent or reduce bacterial colonization and biofilm formation in healthcare settings is essential. A promising approach involves adding antibacterial metal-based nanoparticles into materials to create nanocomposites with antibacterial properties. However, their cytotoxicity to human cells remains a significant concern. Current research aims to balance antibacterial effectiveness with decreased toxicity to human cells. This study provides a comparative in vitro analysis of the cytotoxic effects of seven commonly used metal-based commercial nanoparticles: Ag, ZnO, TiO₂, CeO₂, MgO, ZrO₂, and Bi₂O₃. We evaluated their effects on bacteria related to nosocomial infections (E. coli, S. aureus, P. aeruginosa, and S. mutans) as well as relevant human eukaryotic cells (osteoblasts, fibroblasts, keratinocytes, and adipose-derived mesenchymal stem cells). Additionally, we characterized the nanoparticles’ chemical composition, size, shape, surface area, zeta-potential, hydrodynamic radius, and crystalline structure, along with the pH and conductivity of their aqueous suspensions. Our findings identify nanoparticle types and concentrations that offer optimal cytocompatibility and antibacterial activity, providing crucial guidance for developing safer and more effective antibacterial materials for targeted clinical applications.

This study explores the enhancement of thermoelectric performance in carbon nanotubes (CNTs) via targeted sulfur doping at the central region of the nanotube structure. Carbon nanotubes exhibit very good electrical conductivity, providing unique advantages at the nanoscale. However, CNTs have very high thermal conductivity which limits the thermoelectric efficiency, measured by the value of merit (ZT). To explore this mechanism of CNT doping, a multi-scale computational study has been developed using the density functional tight binding (DFTB) and non-equilibrium Green’s function (NEGF) formalism to study the effect of sulfur addition on the electronic structure of each single-walled CNT and the phonon transport properties of the CNT. Computational studies show that sulfur dopants introduce localized electronic states near the Fermi level that significantly increase the Seebeck coefficient while preserving the high electrical conductivity of CNTs. The sulfur atoms also act as phonon scatterers, thereby spreading the heat flux and reducing the thermal conductivity of the lattice while scattering phonons. The combination of these electronic and phononic improvements results in significant improvements in the ZT values of typical thermoelectric-based cycles. These results provide a practical route to effectively reduce interdependent thermoelectric parameters, and inform the future development of CNT-based materials for new energy conversion applications.

The pulsed plasma in liquid (PPL) method is a simple and versatile technique for synthesizing metal nanoparticles (NPs). Depending on the type of solution employed, this method can yield metal NPs as well as carbide and nitride nanoparticles. PPL experiments were conducted using Ni electrodes in various solutions, including ultra-pure water (UPW), ethylene glycol (EG), ethanol (EtOH), and xylene, and the resulting products were characterized. The results revealed that different solvent combinations led to the formation of metallic, carbon-dissolved metallic, and metal carbide NPs. When UPW was used, metallic Ni NPs were obtained as the main phase along with oxide phases. In contrast, a mixed solution of UPW and EG produced only metallic Ni NPs. The addition of EtOH to this UPW-EG mixture resulted in lattice expansion owing to interstitial carbon dissolution, with the carbon content increasing in proportion to the EtOH concentration. The Ni₃C phase appeared near the solubility limit. The highest carbon incorporation was achieved when xylene was used, yielding a two-phase system consisting of carbon-dissolved Ni and Ni₃C NPs. X-ray diffraction, X-ray absorption fine structure, scanning electron microscopy, and transmission electron microscopy analyses confirmed that the synthesized NPs, typically smaller than 10 nm, exhibited solvent-dependent structural features, including metallic Ni, carbon-dissolved Ni, and Ni₃C phases. These results demonstrate the versatility of the PPL method for tailoring the structural phases of Ni NPs and highlight its potential for synthesizing metastable dual-phase nanomaterials.

Superparamagnetic Fe₃O₄ nanoparticles were specifically designed with a polydopamine (PDA) and folic acid (FA) coating to enhance the availability of organic functional groups at the surface, facilitating the interactions with transition metal ions and drugs. Such nanoparticles were here denoted Fe₃O₄@PDA-FA. Their synthesis and characterization were carefully performed, including thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential measurements, and transmission electron microscopy (TEM). The capture of cobalt(II), copper(II), and zinc(II) ions was successfully demonstrated, revealing the great potential of the Fe₃O₄@PDA-FA nanoparticles in magnetic nanohydrometallurgy (MNHM). The Fe₃O₄@PDA-FA nanoparticles also exhibited good performance in the capture and magnetic transport of buparvaquone, a drug with pharmacological activity against leishmaniasis, as well as antitumor action. The observed drug capture response exhibited a pronounced enhancement in the presence of cobalt(II) ions, which seems to play a role in mediating the interaction between the target molecule and the PDA-FA coating.

Graphical abstract