Formation Mechanism Of Nanoparticles Research Articles

Core-shell gelatin-chitosan nanoparticles with lysozyme responsiveness formed via pH-drive and transglutaminase cross-linking.

Lysozyme-responsive nanoparticles were fabricated using a hydrophilic protein (gelatin type A) as the core and a hydrophobic polysaccharide (chitosan) as the shell. In this study, curcumin was used as a model molecule for encapsulation and promoted the aggregation of gelatin nanoparticles. Transglutaminase catalyzed both intra-molecular cross-linking within gelatin and inter-molecular cross-linking between gelatin and chitosan. The formation mechanism of gelatin nanoparticles was investigated by molecular docking simulations, circular dichroism spectroscopy, UV-Vis spectroscopy, turbidity analysis, and dynamic light scattering. Results indicated that pH-driven processes can induce molecular conformational changes of gelatin. However, these alone are insufficient to induce nanoparticle formation. Hydrogen bonding, Pi-alkyl interactions, Pi-Pi interactions, and van der Waals forces between gelatin and curcumin are crucial for the core formation. The coating mechanism of chitosan involved covalent bonds catalyzed by transglutaminase and electrostatic interactions, verified by dynamic light scattering and Fourier transform infrared spectroscopy. Physicochemical properties characterization revealed that the core-shell nanoparticles exhibited a maximum encapsulation efficiency of 97.2 ± 0.3 % and an average particle size of 120 ± 21 nm. The core-shell nanoparticles exhibited high thermal and pH stability, with curcumin retention rates exceeding 80 % under acidic, neutral, and weakly alkaline conditions, and detained thermal degradation up to 90 °C. Additionally, lysozyme responsiveness was evaluated by controlled curcumin release with varying lysozyme concentrations, through which enzymatic hydrolysis of chitosan by lysozyme triggered an increased release rate. In summary, core-shell nanoparticles synthesized from gelatin and chitosan may be effective target delivery systems for curcumin.

Formation mechanism and stability of ternary nanoparticles based on Mesona chinensis polysaccharides-walnut protein hydrolysates for icariin delivery

Polysaccharide-protein complexes have proven to be effective nano-carrier with high stability. In this work, walnut protein hydrolysates (WPH) prepared through limited enzymolysis were considered as encapsulation carriers to solve the limited water solubility and bioavailability of icariin, a bioactive compound in functional foods. The pH-driven method was employed to prepare WPH-icariin nanoparticles (WPHI). Their characterization, formation, digestive properties, and immunomodulatory activity were investigated. The results showed that WPHI possessed superior encapsulation efficiency (82.35 %) and loading capacity (137.2 μg/mg) for icariin. Its water solubility (1647 μg/mL) and bioavailability (94.86 %) were significantly improved, by over 80 and 30 times, respectively. The combination of WPH with icariin resulted in the formation of irregular lamellar structure through hydrophobic, electrostatic, and disulfide bonds interactions. Moreover, WPHI demonstrated significant immunomodulatory activity, and thermal and digestive stabilities (> 93 %), but extremely poor pH and salt tolerance. To address these issues, Mesona chinensis polysaccharide (MCP)-WPHI was prepared. The incorporation of MCP significantly improved the physicochemical stability of nanoparticles. Compared to WPHI, MCP-WPHI showed improved pH, thermal, salt tolerance (0–250 mM), and storage stability. This study expanded the application of WPH and MCP in delivering icariin while providing new insights for developing multifunctional high-nutritional-quality food ingredients.

Ion-Doped Iron-Based nanoparticles with enhanced magnetic properties: Synthesis and formation mechanism via coprecipitation

Iron-based magnetic nanoparticles have gained significant attention in biomedicine. However, the magnetic properties of iron-based nanoparticles prepared through coprecipitation methods often do not meet application requirements. This study aims to enhance the performance of iron-based magnetic nanoparticles by synthesizing them via the coprecipitation method and doping them with Mn2+, Zn2+, and Co2+ ions in various ratios. Among these, Zn-doped nanoparticles with a 0.6 ratio (ZION-6) exhibits the highest saturation magnetization intensity of 98 emu/g sample and the highest r2 values of 165.2 mM−1·s−1, making them an effective T2 MRI contrast agent. Our investigation into the coprecipitation process revealed a formation mechanism for ion-doped magnetic iron-based nanoparticles. This mechanism involves the formation of an intermediate phase, α-FeOOH, followed by phase transformation, ion doping, and the aggregation of small particles to yield the final magnetic nanoparticles. This research could pave the way for developing magnetic nanoparticles with improved properties for biomedical applications.

Preparation of gold nanoparticles by photolysis and radiolysis in alcohol solutions of functional hyperbranched polyorganosiloxane/H[AuCl4]: Effect of irradiation mode on nanoparticle size and formation mechanism

Ethanol solutions of functional hyperbranched polyorganosiloxanes (0.2 vol%) with a molar ratio of NH2(CH2)2NH-/H[AuCl4]x3H2O of 8/1 were used as precursors for nanocomposite preparation using UV photolysis and X-ray radiolysis. It was shown that various irradiation modes provide the synthesis of gold nanoparticles (AuNPs) with tunable sizes and narrow size distributions. It was established that size distributions of AuNPs depend on the excitation wavelength. AuNPs with an average size of 3.5 nm were obtained by the direct excitation of gold ions using UV light with λmax = 365 nm. Meanwhile, the action of a higher energy light (λ = 254 nm) on the metal polymer complexes resulted in formation of ultra-small nanoparticles with an average size of 1.5 nm, presumably due to the increased efficiency of their nucleation process. In the case of radiolysis with X-rays, reduction of Au3+ ions occurs due to reactions with radicals produced from ethanol and leads to the formation of AuNPs of 2–3 nm. Thus, the size distribution of the prepared AuNPs may be controlled by the irradiation mode, which critically affects nanomaterial properties. Additionally nanoparticles obtained by photochemical or radiation-chemical methods are free of chemical impurities, which is important for the development of functional materials.

Discovery of Molecular Intermediates and Nonclassical Nanoparticle Formation Mechanisms by Liquid Phase Electron Microscopy and Reaction Throughput Analysis

Formation kinetics of metal nanoparticles are generally described via mass transport and thermodynamics‐based models, such as diffusion‐limited growth and classical nucleation theory (CNT). However, metal monomers are commonly assumed as precursors, leaving the identity of molecular intermediates and their contribution to nanoparticle formation unclear. Herein, liquid phase transmission electron microscopy (LPTEM) and reaction kinetic modeling are utilized to establish the nucleation and growth mechanisms and discover molecular intermediates during silver nanoparticle formation. Quantitative LPTEM measurements show that their nucleation rate decreases while growth rate is nearly invariant with electron dose rate. Reaction kinetic simulations show that Ag4 and Ag− follow a statistically similar dose rate dependence as the experimentally determined growth rate. We show that experimental growth rates are consistent with diffusion‐limited growth via the attachment of these species to nanoparticles. The dose rate dependence of nucleation rate is inconsistent with CNT. A reaction‐limited nucleation mechanism is proposed and it is demonstrated that experimental nucleation kinetics are consistent with Ag42+ aggregation rates at millisecond time scales. Reaction throughput analysis of the kinetic simulations uncovered formation and decay pathways mediating intermediate concentrations. We demonstrate the power of quantitative LPTEM combined with kinetic modeling for establishing nanoparticle formation mechanisms and principal intermediates.

Discovering Nanoparticle Formation Mechanisms and Molecular Intermediates with Liquid Phase Electron Microscopy and Reaction Networks

Discovering Nanoparticle Formation Mechanisms and Molecular Intermediates with Liquid Phase Electron Microscopy and Reaction Networks

Chalcogen-Based Precursors for Transition Metal (Co, Ni) Phosphides: (Di)chalcogenide-to-Phosphide Transformation via Chemical Extraction of Chalcogenides.

The chemical properties of polymorphic compounds are highly dependent on their stoichiometry and atomic arrangements, making certain phases technologically more important. Selective development of these phases is challenging. This study introduces a method where chalcogenide atoms from metal chalcogenides are chemically extracted by trioctylphosphine (TOP) and substituted with phosphide. Using this approach, dithiocarbamate/xanthate complexes of cobalt and nickel were employed for the selective synthesis of pure metal sulfides or phosphides. Optimization yielded either sulfur-deficient phases (Ni3S2, Co9S8) or a complete transformation to phosphides (Ni2P, CoP). Likewise, for the first time, selenobenzoate complexes of Ni and Co were used for the synthesis of transition metal diselenides (NiSe2, CoSe2), which could then be converted to metal phosphides (Ni2P, Co2P). The synthesis used solution-phase thermal decomposition with various precursors, surfactants, and temperatures. With TOP, different phases of metal chalcogenides, metal phosphides, and mixed metal phosphide nanomaterials (NiS, Ni3S2, Co9S8, NiSe2, CoSe2, Ni2P, Ni5P4, Co2P, CoP, and Ni2-xCoxP) were obtained by varying reaction conditions. The formation mechanism of nickel and cobalt phosphide nanoparticles from precursors is proposed, demonstrating that presynthesized metal chalcogenides can be transformed into phosphides, opening a new research avenue for dimensionally controlled metal chalcogenides as templates for metal phosphides.

Recent Advances in Efficient Lutein-Loaded Zein-Based Solid Nano-Delivery Systems: Establishment, Structural Characterization, and Functional Properties.

Plant proteins have gained significant attention over animal proteins due to their low carbon footprint, balanced nutrition, and high sustainability. These attributes make plant protein nanocarriers promising for applications in drug delivery, nutraceuticals, functional foods, and other areas. Zein, a major by-product of corn starch processing, is inexpensive and widely available. Its unique self-assembly characteristics have led to its extensive use in various food and drug systems. Zein's functional tunability allows for excellent performance in loading and transporting bioactive substances. Lutein offers numerous bioactive functions, such as antioxidant and vision protection, but suffers from poor chemical stability and low bioavailability. Nano-embedding technology can construct various zein-loaded lutein nanodelivery systems to address these issues. This review provides an overview of recent advances in the construction of zein-loaded lutein nanosystems. It discusses the fundamental properties of these systems; systematically introduces preparation techniques, structural characterization, and functional properties; and analyzes and predicts the target-controlled release and bioaccessibility of zein-loaded lutein nanosystems. The interactions and synergistic effects between Zein and lutein in the nanocomplexes are examined to elucidate the formation mechanism and conformational relationship of zein-lutein nanoparticles. The physical and chemical properties of Zein are closely related to the molecular structure. Zein and its modified products can encapsulate and protect lutein through various methods, creating more stable and efficient zein-loaded lutein nanosystems. Additionally, embedding lutein in Zein and its derivatives enhances lutein's digestive stability, solubility, antioxidant properties, and overall bioavailability.

Bimetallic nanoparticles via microemulsions: The effects of concentration in surface composition

The precise control of surface composition is crucial for enhancing the efficiency of bimetallic nanocatalysts. The scarcity and contradictory nature of experimental results keep open the question of whether reactant concentration promotes the enrichment of the nanoparticle surface with the slower reduction metal. A computer simulation study is carried out to thoroughly investigate how the initial concentration of metals salts modifies the resulting surface for various metal pairs and under different microemulsion compositions. Across all cases, it was observed that less Au is located at the surface as concentration increases. The resulting surface compositions are explained based on the relative rates of the two metals, which consider not only the reduction rate of particular metal pair but also factors such as the concentration of reactants, the intermicellar exchange rate, and the contribution of ripening to growth. This study provides a comprehensive understanding of the mechanism of nanoparticle formation in microemulsions and enables the proposal of practical guidelines for obtaining bimetallic nanoparticles with customized surfaces.

Preparation and characterization of self-assembling nanoparticles in Gancao Ganjiang decoction

Gancao Ganjiang decoction (GGD) is one of the classic formulas in China known for its effective therapeutic effects in treating various diseases. Component research before and after the compatibility of Gancao and Ganjiang revealed that 6-gingerol content considerably changed. Compared with the decoction of Ganjiang, 6-gingerol in GGD demonstrated improved solubility. It was assumed that the partially hydrophilic glycyrrhizic acid and 6-gingerol self-assembled into nanoparticles, which then improved the solubility of 6-gingerol. The self-assembled nanoparticles in GGD were separated and characterized. Subsequently, 6-gingerol–glycyrrhizic acid nanoparticles (6-Gin-Gly NPs) were further prepared and characterized via dynamic light scattering (DLS) and transmission electron microscope (TEM). The formation mechanism of the self-assembled nanoparticles was examined using ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR), electrospray ionization–mass spectrometry (ESI-MS), and molecular docking. The in vitro antioxidant activity of the 6-Gin-Gly NPs was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino bis(3-ethylbenzothiazoline-6- sulfonic acid)+ (ABTS+) free radical scavenging assays, which confirmed that the nanoparticles considerably enhanced their in vitro antioxidant capacity. In this study, the solubility of insoluble components was improved by the formation of self-assembled nanoparticles, which provided substantial reference data for the study of complicated multi-component interaction in herbal medicine decoction.

Mechanism of Nanoparticle Formation under Reduction of Oxygen-Containing Cobalt(II) Compounds with Hydrogen

Mechanism of Nanoparticle Formation under Reduction of Oxygen-Containing Cobalt(II) Compounds with Hydrogen

Elucidation of Formation Mechanism of Solid Electrolyte Nanoparticles and High-Speed Synthesis

Elucidation of Formation Mechanism of Solid Electrolyte Nanoparticles and High-Speed Synthesis

Size-controlled synthesis of copper oxide nanoparticles with a supercritical hydrothermal synthesis method

Supercritical hydrothermal synthesis (SCHS) is a promising technique for the preparation of copper oxide nanoparticles with fast reaction rate, green efficiency and low cost. In this paper, nanoparticles of copper oxide ranging from 53.0 to 94.0 nm were synthesized by supercritical hydrothermal method. The effects of different precursor concentrations, alkali addition, reaction pressure, reaction temperature and reaction time on the particle size, morphology and particle uniformity of copper oxide nanoparticles were also investigated, and the mechanism of each parameter was analyzed. The growth kinetic equation of copper oxide nanoparticles under supercritical hydrothermal conditions was established by analyzing the influence laws of temperature and reaction time on the grain size of the products. Further, the growth activation energy and the growth mechanism controlled by the grain surface process was obtained. The formation mechanism of copper oxide nanoparticles in rod form was analyzed by TEM results.

Preparation of indapamide-HP-β-CD and indapamide-PVP nanoparticles by supercritical antisolvent technology: Experimental and DPD simulations

The poor aqueous solubility of indapamide (INP) limits its applicability in various biomedical applications. To overcome this issue, nanosized INP particles (INP-HP-β-CD NPs and INP-PVP-K30 NPs) were fabricated using the supercritical antisolvent (SAS) approach to improve the bioavailability of INP. The process, formula, and supercritical antisolvent process were optimized using single-factor and orthogonal methods. The tiny INP-HP-β-CD NPs with a particle size of 142.5 nm and INP-PVP-K30 NPs with a particle size of 150.4 nm were obtained under optimum conditions. Further analysis and characterization, such as SEM, FTIR, XRD, DSC, 1H NMR, and dissipative particle dynamics (DPD) simulations, were carried out to verify the formation mechanism of the INP complex nanoparticles. The altered physical state of INP from crystalline to amorphous loaded onto the polymer resulted in a significant improvement in the solubility and dissolution rate and high biocompatibility with cells compared to raw INP. Therefore, we propose that INP nanoparticles processed by a supercritical antisolvent process can be used as an advanced drug delivery system, especially for insoluble drugs.

Synthesis of Gold Clusters and Nanoparticles Using Cinnamon Extract-A Mechanism and Kinetics Study.

In this work, UV-Vis spectrophotometry, High Resolution Scanning Transmission Electron Microscopes and selected experimental conditions were used to screen the colloidal system. The obtained results complement the established knowledge regarding the mechanism of nanoparticle formation. The process of gold nanoparticles formation involves a two-step reduction of Au ions to Au(0); atom association and metastable cluster formation; autocatalytic cluster growth; ultra-small particle formation (1-2 nm, in diameter); particle growth and larger particles formation; and further autocatalytic crystal growth (D > 100 nm). As a reductant of Au(III) ions, a cinnamon extract was used. It was confirmed that eugenol as one of the cinnamon extract compounds is responsible for fast Au(III) ion reduction, whereas cinnamaldehyde acts as a gold-particle stabilizer. Spectrophotometry studies were carried out to track kinetic traces of gold nanoparticle (D > 2 nm) formation in the colloidal solution. Using the Watzky-Finke model, the rate constants of nucleation and autocatalytic growth were determined. Moreover, the values of energy, enthalpy and entropy of activation for stages related to the process of nanoparticle formation (Index 1 relates to nucleation, and Index 2 relates to the growth) were determined and found to be E1 = 70.6 kJ, E2 = 19.6 kJ, ΔH1 = 67.9 kJ/mol, ΔH2 = 17 kJ/mol, ΔS1 = -76.2 J/(K·mol), ΔS2 = -204.2 J/(K·mol), respectively. In this work the limitation of each technique (spectrophotometry vs. HRSTEM) as a complex tool to understand the dynamic of the colloidal system was discussed.

Microstructural evolution during the crystallization process of sol-gel derived PbZrO3 nanocomposite thin films

For the application of dielectric materials in energy storage, nanocomposition is one of the effective methods to improve their electric breakdown field strength. In this study, PbZrO3-Al2O3 nanocomposite films were prepared by combined thermal evaporation deposition and a sol–gel method. By changing the annealing time, the crystallization process of PbZrO3 matrix and the formation mechanism of Al2O3 nanoparticles were studied, and the microstructure evolution process of composite films was elucidated. The results indicate that before the final annealing at 700 ℃, Al atoms have diffused into the amorphous PbZrO3 film, and some fine grains of the perovskite phase have been generated at the bottom of the film. As the annealing time increases, the perovskite grains grow along the out of plane direction of the thin film to form columnar grains, and Al atoms diffuse into the perovskite phase lattice; As the annealing time further increases, Al2O3 nanoparticles began to precipitate at the interlayer interfaces of PbZrO3 coating layers, forming a layered distribution. The changes in electric properties with annealing time also demonstrate the microstructural evolution process of the composite film during annealing. Therefore, controlling annealing time is an effective means to control the microstructure and electric properties of composite films prepared by the new method for the application of energy storage.

Formation mechanism of herpetrione self-assembled nanoparticles based on pH-driven method

The self-assembled nanoparticles (SAN) formed during the decoction process of traditional Chinese medicine (TCM) exhibit non-uniform particle sizes and a tendency for aggregation. Our group found that the pH-driven method can improve the self-assembly phenomenon of Herpetospermum caudigerum Wall., and the SAN exhibited uniform particle size and demonstrated good stability. In this paper, we analyzed the interactions between the main active compound, herpetrione (Her), and its main carrier, Herpetospermum caudigerum Wall. polysaccharide (HCWP), along with their self-assembly mechanisms under different pH values. The binding constants of Her and HCWP increase with rising pH, leading to the formation of Her-HCWP SAN with a smaller particle size, higher zeta potential, and improved thermal stability. While the contributions of hydrogen bonding and electrostatic attraction to the formation of Her-HCWP SAN increase with rising pH, the hydrophobic force consistently plays a dominant role. This study enhances our scientific understanding of the self-assembly phenomenon of TCM improved by pH driven method.

Investigation on different additions as candidates for nano-oxide particles in nickel-based ODS superalloys

Four nickel-based oxide dispersion strengthened (ODS) superalloys with the additions of YH2, Y2O3, La2O3 and CeO2 (denoted as ODS-Y1 ODS-Y2, ODS-La and ODS-Ce) are prepared, respectively. The tensile tests at temperatures ranging from room temperature (RT) to 1000 °C were conducted on them. In this work, by means of microstructure characterization and theoretical modeling, different strengthening mechanisms including grain boundary strengthening, solution strengthening, dislocations and dispersion strengthening, were estimated to contribute to the yield strength in different degrees, which would help to further enhance the tensile properties of alloys through nanoparticles optimization thereafter, and the formation and evolution mechanism of nanoparticles are discussed. The results show that ODS-Y1 has the smallest particles and the best comprehensive mechanical property in the tested alloys. The nanoparticles having M-Al-rich (M = Y, La, Ce) cores and Ti-O-rich shells structure are observed in nickel-based ODS superalloys, and the M-Al-O are preferentially formed, due to the higher diffusion rate of Al atom and high M/Al value. Then Ti and O atoms diffuse to the surface of nanoparticles, forming a core-shell structures in the later precipitation stages.

Nanoparticle formation mechanisms and molecular intermediates revealed by liquid phase EM and reaction pathway analysis

Nanoparticle formation mechanisms and molecular intermediates revealed by liquid phase EM and reaction pathway analysis

Insights into Ni3TeO6 calcination via in situ synchrotron X-ray diffraction.

The versatility of metal tellurate chemistry enables the creation of unique structures with tailored properties, opening avenues for advancements in a wide range of applications. However, precise nanoengineering of Ni3TeO6, a ceramic Ni tellurate with a broad variety of properties, like electrical, magnetic, photocatalytic and multiferroic properties, demands a deep understanding of the synthesis process, which is strongly influenced by experimental parameters. This study delves into the formation mechanism of Ni3TeO6 nanoparticles during calcination of hydrothermally produced precursors, using in situ synchrotron X-ray diffraction, complemented by post-mortem TEM and XPS, and thermal analysis. The results reveal a reaction sequence involving dehydration and dehydroxylation of stoichiometric Ni/Te oxyhydroxide coordinated by Te. This oxyhydroxide can be schematically represented by a formula of (3Ni/Te)(OOH)4·H2O. Subsequently, preferential nucleation of Ni3TeO6 occurs. Further calcination after full crystallization of Ni3TeO6 leads to the formation of a different Ni tellurate (NiTeO4) phase as an impurity. These findings clarify the reactions occurring during calcination of Ni/Te mixed precursors, which have frequently been inferred from empirical and post-mortem reports but not confirmed via comprehensive and in situ guided explorations.