Surface Properties Of Nanoparticles Research Articles

Study of structural, optical, surface and electrochemical properties of Co3O4 nanoparticles for energy storage applications

Study of structural, optical, surface and electrochemical properties of Co3O4 nanoparticles for energy storage applications

Impact of Nebulization on the Physicochemical Properties of Polymer-Lipid Hybrid Nanoparticles for Pulmonary Drug Delivery.

Nanoparticles (NPs) have shown significant potential for pulmonary administration of therapeutics for the treatment of chronic lung diseases in a localized and sustained manner. Nebulization is a suitable method of NP delivery, particularly in patients whose ability to breathe is impaired due to lung diseases. However, there are limited studies evaluating the physicochemical properties of NPs after they are passed through a nebulizer. High shear stress generated during nebulization could potentially affect the surface properties of NPs, resulting in the loss of encapsulated drugs and alteration in the release kinetics. Herein, we thoroughly examined the physicochemical properties as well as the therapeutic effectiveness of Infasurf lung surfactant (IFS)-coated PLGA NPs previously developed by us after passing through a commercial Aeroneb® vibrating-mesh nebulizer. Nebulization did not alter the size, surface charge, IFS coating and bi-phasic release pattern exhibited by the NPs. However, there was a temporary reduction in the initial release of encapsulated therapeutics in the nebulized compared to non-nebulized NPs. This underscores the importance of evaluating the drug release kinetics of NPs using the inhalation method of choice to ensure suitability for the intended medical application. The cellular uptake studies demonstrated that both nebulized and non-nebulized NPs were less readily taken up by alveolar macrophages compared to lung cancer cells, confirming the IFS coating retention. Overall, nebulization did not significantly compromise the physicochemical properties as well as therapeutic efficacy of the prepared nanotherapeutics.

Iterative nanoparticle bioengineering enabled by x-ray fluorescence imaging.

Nanoparticles (NPs) are currently developed for drug delivery and molecular imaging. However, they often get intercepted before reaching their target, leading to low targeting efficacy and signal-to-noise ratio. They tend to accumulate in organs like lungs, liver, kidneys, and spleen. The remedy is to iteratively engineer NP surface properties and administration strategies, presently a time-consuming process that includes organ dissection at different time points. To improve this, we propose a rapid iterative approach using whole-animal x-ray fluorescence (XRF) imaging to systematically evaluate NP distribution in vivo. We applied this method to molybdenum-based NPs and clodronate liposomes for tumor targeting with transient macrophage depletion, leading to reduced accumulations in lungs and liver and eventual tumor detection. XRF computed tomography (XFCT) provided 3D insight into NP distribution within the tumor. We validated the results using a multiscale imaging approach with dye-doped NPs and gene expression analysis for nanotoxicological profiling. XRF imaging holds potential for advancing therapeutics and diagnostics in preclinical pharmacokinetic studies.

Optical properties of semiconductor nanoparticles doped with 3d and 4f block elements

Doped inorganic nanoparticles (NPs) have enabled researchers across multiple disciplines to create new materials with unique optical, electronic, magnetic, electrical, chemical, and/or compositional properties. In the quest for generating newer functional materials with controlled optical and electronic properties, the use of d- and f-block elements as dopants in the inorganic NPs remain at the forefront of research. This article summarizes experiments that identify the important control parameters, in the form of NP core and surface properties, for promoting host-sensitized dopant emission from d- and f-doped inorganic/semiconductor NPs. We conclude that energy offsets between the dopant and NP electronic levels and an understanding of the charge trapping mechanisms can be used to predict dopant luminescence, and we claim that these features can be used to choose NP host materials by design, rather than by trial and error.

Insights Into Formation and Growth of Colloidal Multielement Alloy Nanoparticles in Solution through In Situ Liquid Cell TEM Study

AbstractThe nucleation and growth of nanoparticles are critical processes determining the size, shape, and properties of resulting nanoparticles. However, understanding the complex mechanisms guiding the formation and growth of colloidal multielement alloy nanoparticles remains incomplete due to the involvement of multiple elements with different properties. This study investigates in situ colloidal synthesis of multielement alloys using transmission electron microscopy (TEM) in a liquid cell. Two different pathways for nanoparticle formation in a solution containing Au, Pt, Ir, Cu, and Ni elements, resulting in two distinct sets of particles are observed. One set exhibits high Au and Cu content, ranging from 10 to 30 nm, while the other set is multi‐elemental, with Pt, Cu, Ir, and Ni, all less than 4 nm. The findings suggest that, besides element miscibility, metal ion characteristics, particularly reduction rates, and valence numbers, significantly impact particle composition during early formation stages. Density functional theory (DFT) simulations confirm differences in nanoparticle composition and surface properties collectively influence the unique growth behaviors in each nanoparticle set. This study illuminates mechanisms underlying the formation and growth of multielement nanoparticles by emphasizing factors responsible for chemical separation and effects of interplay between composition, surface energies, and element miscibility on final nanoparticles size and structure.

Interfacial polymerization achieved integration of pore size adjustment, electrostatic repulsion and physical adsorption into one to inhibit polysulfide shuttle for enhanced lithium–sulfur battery

The application of lithium-sulfur battery is seriously hindered by the shuttle of dissolved polysulfide between sulfur cathode and lithium anode, by which is not selectively inhibited by the conventional separator. Developing functional separator is considered as a preferred solution for this issue, but it is always challenged by the tedious preparation process. Herein, interfacial polymerization (IP) is employed to modify the surface property of ZrO2 nanoparticles embedded polyetherimide (PZ) based separator, and the integration of pore size adjustment, electrostatic repulsion and physical adsorption into one is facilely achieved to effectively inhibit the polysulfide shuttle. Consequently, the optimized PZ separator presents a high lithium-ion transference number (0.55) and diffusion coefficient (2.16 × 10−8 cm s−1). Compared with the pristine one, the electrochemical performance of the assembled lithium-sulfur battery is obviously enhanced, and an initial discharge specific capacity of 1242 mAh g−1 and a capacity retention of 68 % after 200 cycles are obtained.

Effect of ligand and shell densities on the surface structure of core-shell nanoparticles self-assembled from function-spacer-lipid constructs.

Biomolecular corona is the major obstacle to the clinical translation of nanomedicines. Since corona formation is governed by molecular interactions at the nano-bio interface, nanoparticle surface properties such as topography, charge and surface chemistry can be tuned to manipulate biomolecular corona formation. To this end, as the first step towards a deep understanding of the processes of corona formation, it is necessary to develop nanoparticles employing various biocompatible materials and characterize their surface structure and dynamics at the molecular level. In this work, we applied molecular dynamics simulation to study the surface structure of organic core-shell nanoparticles formed by the self-assembly of synthetic molecules composed of a DOPE lipid, a carboxymethylglycine spacer and biotin. Lipid moieties form the hydrophobic core, spacer motifs serve as a hydrophilic shell and biotin residues function as a targeting ligand. By mixing such function-spacer-lipid, spacer-lipid and lipid-only constructs at various molar ratios, densities of the ligand and spacer on the nanoparticle surface were modified. For convenient analysis of the structure and dynamics of all regions of the nanoparticle surface, we compiled topography maps based on atomic coordinates. It was shown that an increase in the density of the shell does not reduce exposure of the core, but increases shell average thickness. Biotin, due to its alkyl valeric acid chain and spacer flexibility, is localized primarily near the hydrophobic core and its partial presentation on the surface occurs only in nanoparticles with higher ligand densities. However, an increase in biotin density leads to its clustering. In turn, ligand clustering diminishes the stealth properties of the shell and targeting efficiency. Based on nanoparticle surface structures, we determined the optimal density of biotin. Experimental studies reported in the literature confirm these conclusions. We also suggest design tips to achieve the preferred biotin presentation. Simulation results are consistent with the synchrotron SAXS profile. We believe that such studies will contribute to a better understanding of nano-bio interactions towards the rational design of efficient drug delivery systems.

Photocatalytic and surface properties of titanium dioxide nanoparticles in soil solutions

Effet of chemical compounds in soil solution to the photocatalytic activity of TiO2 NPs.

Structural and Surface Properties of pH-Varied Fe2O3 Nanoparticles: Correlation with Antibacterial Properties.

Hematite (Fe2O3) nanoparticles were synthesized using a hydrothermal synthesis route under different pH conditions (pH ∼8,10,11.5) (i.e., different ratios of H+/OH- ions). The sample synthesized at pH 10 had better motility toward the bacterial surface due to having an overall positive charge (ξ-potential = +11.10), leading to a minimal hydrodynamic size (Dτ = 186.6). The results are discussed in light of the relative ratio of H+/OH- that may affect bond formation by influencing the electronic clouds of the participating ions that can modify the structure. This, in turn, modifies crystallinity, strain, disorder, surface termination, and thereby, the surface charge, which has been correlated to the antibacterial properties of the nanoparticles due to the interaction between the respective opposite charges on the nanoparticle surface and bacterial cell wall. The structural modifications were correlated to all of these parameters in this work.

Controlling magnetic and surface properties of cobalt ferrite nanoparticles: A comparison of co-precipitation and solvothermal synthesis methods

Cobalt ferrite (CoFe2O4) nanoparticles have been synthesized using two different wet-chemical methods: co-precipitation and solvothermal. Mesoporous cobalt ferrite nanoparticles were prepared using the co-precipitation method with 4, 6, and 8 wt% of Pluronic P123 and with the solvothermal method with 10, 15, and 20 wt% of PEG-4000. X-ray diffractometry confirmed the formation of a single-phase spinel structure. The saturation magnetization of the nanoparticles increased from 48 to 64 emu/g as the P123 concentration increased from 4 to 8 % wt, and decreased from 72 to 62 emu/g as the PEG-4000 concentration increased from 10 to 20 % wt. Generally, the samples synthesized by the solvothermal method had a higher specific surface area than those prepared by the co-precipitation method. In comparison to other samples, the 10 % PEG-4000 sample had the highest specific surface area and showed the highest level of dye degradation (93 %). The findings demonstrated that the concentration of Pluronic P123 and PEG-4000 had an impact on the saturation magnetization and specific surface area of the nanoparticles.

Effect of Surface Properties of Nanoparticles on the Crystallization Behavior of Polypropylene/Polypropylene‐g‐Silica Nanocomposites

AbstractIn order to investigate the effect of surface properties of nanoparticles (NPs) on the crystallization behavior of nanocomposite, three kinds of silica (SiO2) NPs are dispersed in isotactic polypropylene (iPP) matrix by solution blending method. Specifically, the poor compatibility between inorganic bare SiO2 NPs and organic PP matrix triggers the formation of aggregates and induces the fractionated crystallization with two crystallization peaks at higher particle loading (Φ), i.e., main crystallization peak (MCP) and low temperature crystallization peak (LCP, always located at 124.0 °C). Once short PP chains (0.9 × 104 g mol−1) are grafted onto the surface of SiO2 NPs, the nanocomposites with all Φ only exhibit a single MCP which is attributed to the strong interfacial interaction. With the increase of grafting chain length (9 × 104 g mol−1), the more stretched conformation of grafting chains can provide numerous heterogeneous nucleation sites and significantly accelerate the crystallization rate of PP chains near the surface of SiO2 NPs, which lead to the formation of an extra high temperature crystallization peak (HCP, almost kept constant at 133.0 °C). The occurrence of various crystallization peaks implies that the surface properties of nanoparticles play a vital role in the nucleation ability of nanoparticles.

Photo-Catalytic Activity Improvement for Organic Pollutant Removal in Wastewater using Zinc Oxide Quantum Dots: An Experimental and Modeling Study

Photo-catalyst nanoparticles (NPs) find applications in many diverse fields, including environmental remediation, energy conversion, and organic synthesis. By optimizing the nanoparticle's composition, size, morphology, and surface properties, the photo-catalytic performance can be enhanced to develop more efficient and sustainable catalytic systems. This work aligns with this innovative approach and aims to improve the photo-catalytic degradation of Sulfamethoxazole (SMX) through the intensification of the photo-catalyst and the micro-reactor. ZnO-NPs were synthesized using the sol-gel method. Zinc Acetate (Z.A) and sodium hydroxide were used as precursor materials. The resulting ZnO-NPs were characterized for their structure and crystallinity using X-Ray Diffraction (XRD) and the photo-catalytic activity was assessed with a micro-structured polymer reactor. The degradation of SMX through photo-catalysis proceeds through several stages that involve coupled processes, such as the transportation of molecules and chemical reactions. To solve the mathematical equations governing the transport and photocatalytic reaction, COMSOL Multiphysics software was utilized. The characterization results demonstrate the excellent crystallinity and high purity of the synthesized ZnO-NPs, enabling the estimation of the average diameter of the NPs under different synthesis conditions. The grain growth is faster (3.5 hr) at higher temperatures (70, 80, and 90 °C), and slower (4 hr) at lower temperatures (50 and 60°C). The photo-catalytic degradation is significantly more efficient on 16 nm ZnO-NPs than 50 nm ZnO-NPs. At this size, the conversion rate reaches 96%, surpassing the performance of commercial ZnO-NPs, which only degrades 81% of SMX. The conversion rate obtained through simulation is slightly higher than that achieved in the experiments. However, this difference remains negligible, and overall, the model fits well with the experimental data. This validation of the chosen model confirms its reliability and accuracy.

Mathematical Modeling of Carbon Nanoparticle Distribution in Polymer Composites for High Electrical Conductivity: Implications for Green Technologies

A mathematical framework has been formulated to elucidate the conductivity behavior of polymer composites infused with carbon nanoparticles. This linear model, while simplistic, provides a foundational understanding of how factors like nanoparticle morphology, concentration, and surface properties, in conjunction with polymer matrix attributes such as viscosity and surface tension, influence the spatial distribution of these nanoparticles. The overarching aim is to harness the potential of electrically conductive composites in bolstering green technological advancements in sectors like road transport, solar energy, batteries, and environmental conservation. The model underscores the pivotal role of high electrical conductivity in ensuring the efficient, sustainable, and environmentally benign operation of these technologies. This mathematical construct emerges as an instrumental tool, paving the way for the strategic design and optimization of electrically conductive composites tailored for diverse green technology applications.

Comprehensive Analysis of Titanium Oxide Nanoparticle Size and Surface Properties on Neuronal PC-12 Cells: Unraveling Cytotoxicity, Dopaminergic Gene Expression, and Acetylcholinesterase Inhibition.

Titanium oxide nanoparticles can penetrate the blood-brain barrier, infiltrate the central nervous system, and induce neurotoxicity. One of the most often utilized nanoparticles has been investigated for their neurotoxicity in many studies. Nonetheless, there remains an unexplored aspect regarding the comparative analysis of particles varying in size and nanoparticles of identical dimensions, both with and devoid of surface coating. In the current study, we synthesized two differently sized nanoparticles, TiO2-10 (10 nm) and TiO2-22 (22 nm), and nanoparticles of the same size but with a polyvinylpyrrolidone surface coating (TiO2-PVP, 22 nm) and studied their toxic effects on neural PC-12 cells. The results highlighted significant dose- and time-dependent cytotoxicity at concentrations ≥10 μg/mL. The exposure of TiO2 nanoparticles significantly elevated reactive oxygen and nitrogen species levels, IL-6 and TNF-α levels, altered the mitochondrial membrane potential, and enhanced apoptosis-related caspase-3 activity, irrespective of size and surface coating. The interaction of the nanoparticles with acetylcholinesterase enzyme activity was also investigated, and the results revealed a dose-dependent suppression of enzymatic activity. However, the gene expression studies indicated no effect on the expression of all six genes associated with the dopaminergic system upon exposure to 10 μg/mL for any nanoparticle. The results demonstrated no significant difference between the outcomes of TiO2-10 and TiO2-22 NPs. However, the polyvinylpyrrolidone surface coating was able to attenuate the neurotoxic effects. These findings suggest that as the TiO2 nanoparticles get smaller (towards 0 nm), they might promote apoptosis and inflammatory reactions in neural cells via oxidative stress, irrespective of their size.

Amorphous iron oxyhydroxides nano precursors used for Reactive Yellow 84 removal from aqueous solutions

In this research, we investigated the potential use of amorphous iron oxyhydroxides, ferrihydrite (FHY), for the removal of persistent pollutants from aqueous solutions. Ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N, N′-disuccinic acid (EDDS) were used as complexing agents during synthesis aiming to enhance the FHY properties. Synthesized materials were characterized by X-ray diffraction, SEM and TEM Microscopy, N2 sorption/desorption, and FT-IR Spectroscopy for their mineralogy, crystallinity, morphology and size, surface properties, and the organic content in their structure. The addition of chelating agents led to differences in nanoparticles morphology, amorphic degree, and surface properties. Reactive Yellow 84 dye was chosen as a representative refractory pollutant and laboratory-scale adsorption studies were conducted at varying dye concentrations. Ca. 100 % RY 84 dye removal efficiency was achieved within one hour at dye concentrations of 5–10 mg/L for an adsorbent dosage of 1 mg/L FHY. Adsorption kinetics and isothermal studies were considered, the uptake capacity was calculated for each nanomaterial and empiric mechanistic information was derived. The results showed that ferrihydrite exhibits the best performance, with a maximum uptake capacity of 40.73 mg Reactive Yellow 84 dye per gram adsorbent followed by FHY_EDTA and FHY_EDDS (up to 35.86 mg/g). Coupling the adsorption with photodegradation processes led to a significant increase in removal efficiencies of persistent RY 84 from polluted aqueous solution, in good timing, suggesting a feasible alternative at sites where dye concentration in effluents is elevated.

Design of Redispersible High-Drug-Load Amorphous Formulations: Impact of Ionic vs Nonionic Surfactants on Processing and Performance.

Amorphous solid dispersions (ASDs) are an enabling formulation approach used to enhance bioavailability of poorly water-soluble molecules in oral drug products. Drug-rich amorphous nanoparticles generated in situ during ASD dissolution maintain supersaturation that drives enhanced absorption. However, in situ formation of nanoparticles requires large quantities of polymers to release drugs rapidly, resulting in an ASD drug load <25%. Delivering directly engineered drug-rich amorphous nanoparticles can reduce the quantities of polymers significantly without sacrificing bioavailability. Preparation of 90% drug-load amorphous nanoparticles (ANPs) of <300 nm diameter using solvent/antisolvent nanoprecipitation, organic solvent removal, and spray drying was demonstrated previously on model compound ABT-530 with Copovidone and sodium dodecyl sulfate (anionic). In this work, nonionic surfactant d-α-tocopheryl polyethylene glycol succinate (Vitamin E TPGS, or TPGS) was used to prepare ANPs as a comparison. Characterization of ANPs by dynamic light scattering, filtrate potency assay, scanning electron microscopy, and differential scanning calorimetry revealed differences in surface properties of nanoparticles afforded by surfactants. This work demonstrates the importance of understanding the impact of the stabilizing agents on nanoparticle behavior when designing a high-drug-load amorphous formulation for poorly water-soluble compounds as well as the impact on redispersion.

Effect of Organic Coating Variation on the Electric and Magnetic Behavior of Ferrite Nanoparticles.

Organic ligand coatings can modify the surface properties of nanoparticles. With the proper choice of the type of nanoparticles and of the ligand, a targeted modification can be achieved that is suitable for specific applications. In the present work, we employ density functional theory calculations with Hubbard corrections (DFT + U) to treat localized states in order to investigate the magnetic and electrostatic properties of ferrite nanoparticles (CoFe2O4 and Fe2O3) covered with COOH-terminated [oleic acid (OA)] and OH-terminated [diethylene glycol (DEG)] ligands by varying the ligands coverage. OA results in a decrease of the mean magnetic moment for both particles as the coating coverage increases. The magnetic anisotropy (MAE) significantly decreases for CoFe2O4, whereas for Fe2O3 a significant increase of MAE is found as the OA coverage percentage increases. For DEG, the variation of both types of nanoparticles in the magnetic moment and the magnetic anisotropy is not significant since DEG shows a weaker attachment on the surface. As COOH shows a larger percentage of covalent bonding than OH, a larger amount of charge is transferred to both particles when OA is attached on their surface. In this case, the particles possess a higher charge, and thus they can produce a larger electrostatic potential in the neighborhood independently of the screening by the coating. Thus, the repulsive Coulombic forces are enhanced mainly in the OA coating case, resulting in an enhancement of their colloidal stability.

Extensive function of green synthesized titania nanoparticles: Photodegradation of Congo red

Several extensive research studies have explored the advantages of green templates in the synthesis of structure and morphology-controlled photocatalytic nanomaterials. This paper compares the abilities of zingiber rhizome extract (ZE) and tapioca starch extracts (TS) in modifying the surface and optical properties of titania nanoparticles (TNP) synthesized by solgel technique. The synthesized nanocatalysts were characterized using various physicochemical techniques. While zingiber (ginger) extract effectively promotes the formation of dual anatase and rutile phases, tapioca extract supports formation of the single anatase phase of titania. These two extracts were examined for the degradation of Congo red in the presence of sunlight. The photomineralization and recyclability of catalysts were evaluated through total organic content analysis. The easy recovery and reusability of zingiber and tapioca biomasses, along with good control over the growth of nanoparticles, enable them to be implicit novel green templates in the successful synthesis of photoactive mesoporous nanotitania.

Unravelling the Surface Oxidation-Induced Evolution of the Electronic Structure of Gallium.

Gallium is widely used in liquid metal catalyst fabrication, and its oxidized species is a well-known dielectric material. In the past decades, these two species have been well studied separately. However, the surface oxide layer-induced impact on the chemical and electronic structure of (liquid) gallium is still mostly unclear because of the extreme fast formation of thermodynamically stable surface Ga2O3. In this study, we used a combination of direct and inverse photoemission complemented by scanning electron microscopy to examine the surface properties of Ga and Ga oxide (on a SiOx/Si support) and the evolution of the surface structure upon stepwise oxidation and subsequent reduction at an elevated temperature. We find oxidation time-dependent self-limited formation of a substoichiometric Ga2O3-δ surface layer on the Ga nanoparticles. The valence band maximum (conduction band minimum) for this Ga2O3-δ is located at -3.8 (±0.1) eV [1.4 (±0.2) eV] with respect to the Fermi level, resulting in an electronic surface band gap of 5.2 (±0.2) eV. Upon annealing in ultrahigh vacuum conditions, the Ga2O3-δ surface layer can efficiently be removed when using temperatures of 600 °C and higher. This study reveals how the surface properties of Ga nanoparticles are influenced by stepwise oxidation-reduction, providing detailed insights that will benefit the optimization of this material class for different applications.

Interfacial adsorption of gold nanoparticles on arsenian pyrite: New insights for the transport and deposition of gold nanoparticles

Gold nanoparticles (AuNPs) are found extensively in the near-surface Earth system. The transport, aggregation, and deposition of AuNPs have been potentially recognized as an important process and even a fundamental intermediary step both in formation of high-grade gold deposits and in the dispersion of gold into the Earth's surface environment. The interfacial adsorption between AuNPs and sulfide minerals is a long-recognized process regulating transport and deposition of gold in hydrothermal fluids, and the occurance of Au and As in pyrite are often observed in various hydrothermal Au deposits. However, the adsorption behavior of AuNPs on sulfide minerals and the fundamental chemical mechanism for the AuAs relationship remain enigmatic. In this work, we selected citrate as a surrogate for typical natural organic compounds abundantly found in lower-temperature hydrothermal systems and Earth's surface environment, and experimentally investigated the adsorption of negatively charged AuNPs on pyrite and arsenian pyrite under anaerobic conditions. We demonstrate that pyrite and nanoparticle surface properties, and solution chemistry, control the adsorption process. Negligible adsorption of AuNPs on pyrite (absent of As) was verified under all experimental conditions likely due to high electrostatic repulsion. However, we observed AuNPs adsorption on arsenian pyrite and suggest that this interaction is due to negative charge-assisted hydrogen bonds ((−)CAHBs) between hydroxyl/oxyl groups on the surface of arsenian pyrite and carboxyl groups on the citrate capping agent of AuNPs. Also, the lower negative charge density of arsenian pyrite surfaces significantly reduces electrostatic repulsion between both negatively charged AuNPs and arsenian pyrite. The solution pH, coexisting organics (citrate) concentration, and ionic strength are demonstrated to play substantial roles in the adsorption of AuNPs on arsenian pyrite. However, the solution pH appears to be an overriding factor controlling the adsorption of AuNPs which decreases with the increase of pH. With respect to citrate concentration, the adsorption rates of AuNPs onto arsenian pyrite initially decreases, but only slightly, and then increases. Increased ionic strength also promotes the adsorption of AuNPs. Our findings highlight a potentially important role of AuNPs in transport and deposition processes of gold in aqueous mediums, and provide new insights on the geochemical behavior of metal nanoparticles in the hydrothermal systems and Earth's surface environment.