Effect Of Nanoparticle Size Research Articles

Effect of nanoparticle size on their distribution and retention in chronic inflammation sites

Nanomedicines are increasingly researched and used for the treatment of chronic inflammatory diseases. Herein, the effect of the size of nanoparticles on their distribution and retention in chronic inflammatory sites, as compared to healthy tissues, was studied in a mouse model with chronic inflammation in one of the hind footpads. Using PEGylated gold nanoparticles of 2, 10, 100, and 200 nm, we found that although the smaller nanoparticles of 2 and 10 nm showed greater distribution and slower clearance in the inflamed footpad than the relatively larger nanoparticles of 100 and 200 nm, the larger nanoparticles of 100 and 200 nm were more selectively distributed in the inflamed hind footpad than in the healthy hind footpad in the same mouse. Based on these findings, we prepared protein nanoparticles of 100–200 nm with albumin, IgG antibody, or anti-TNF-α monoclonal antibody (mAb). The nanoparticles can release proteins in response to high redox activity and/or low pH, conditions seen in chronic inflammation sites. We then showed that upon intravenous injection, those stimuli-responsive protein nanoparticles distributed more selectively in the inflamed footpad than free proteins and remained longer in the inflamed footpad than similar protein nanoparticles that are not sensitive to high redox activity or low pH. These findings support the feasibility of increasing the selectivity of nanomedicines and protein therapeutics to chronic inflammation sites and prolonging their retention at the sites by innovative nanoparticle engineering.Graphical

Investigation on the size and percentage effects of magnesium nanoparticles on thermophysical properties of reinforced calcium phosphate bone cement by molecular dynamic simulation

In recent years, bone materials and cement innovation have made extraordinary strides. Calcium phosphate cement (CPC) regenerates body tissues and repairs bone and dental defects. Since the presence of nanoparticles (NPs) increased the initial cement strength in terms of the reduction of porosity, magnesium (Mg) NPs were used because of their unique properties. In this study, the effects of various Mg NP percentages and sizes on reinforced cement thermal behavior and mechanical behavior are investigated using the molecular dynamics (MD) simulation method. The changes of Young's modulus (YM), maximum temperature (MT), and ultimate strength (US) were investigated for this reason. The US, YM, and MT of the reinforced cement sample improved from 0.879 to 0.171 MPa to 1.326 and 0.255 MPa, respectively, and from 1321 to 1403 K by raising the NPs percentage to 4%. The radius increase of NPs to 16 Å enhanced the US, YM, and MT to 0.899 MPa, 0.179 MPa, and 1349 K. The MT decreased to 1275 K. The quantity and size of the Mg NPs significantly enhanced the mechanical behavior of the finished cement, according to the findings.

Laser shock forming of metal nanostructures withultrafine gaps.

The nanogaps between metal nanostructures are of great importance in nanotechnology. However, low cost and high precision fabrication of such nanogaps is still a difficult problem. In this paper, a method combining nanosecond laser shock and flexible metal film is proposed to form ultrafine gaps between metal nanostructures. The forming mechanism of ultrafine gaps between metal nanostructures was revealed by studying the superplastic deformation, spatiotemporal evolution of stress and strain, and cooperative deformation of the flexible metal thin film and metal nanostructures under laser shock. On the basis of the mechanism study, the effects of laser parameters and gold nanoparticle size on the forming of ultrafine gaps were further studied, so as to achieve high precision forming of ultrafine gaps (<10n m) between metal nanostructures.

Effect of noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study of active sites

Effect of noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study of active sites

Unravelling the roles of nano-modification in enhancing demulsification: Size effects and strengthened non-covalent interactions

Emerging nano-demulsifiers are efficient functional materials for separating emulsions. However, the size effects of nanoparticles on demulsification and the mechanisms of enhanced demulsification by nano-modification are still unclear. Herein, a nano-demulsifier (SiO2-mANP) was prepared by modifying carboxyl-modified aliphatic nonionic polyether (mANP) with nano-SiO2. Compared to single polyether, the SiO2-mANP significantly reduced the demulsification temperature from 60 °C to room temperature. The demulsification efficiency of the asphaltene-stabilized water-in-oil emulsion reached 91.0% within 10 min at room temperature (dehydration over 99.5% in less than 2 min at 60 °C). The size effects study showed that smaller SiO2-mANP nanoparticles (∼10 nm) performed better in demulsification due to their superior diffusion ability in continuous phase and greater adsorption at the oil-water interface. The electrostatic potential (ESP) and independent gradient model (IGM) were used for the first time to analyze the changes in non-covalent interactions between demulsifiers and water. Nano-modification facilitated the formation of more non-covalent interaction sites, notably hydrogen bonding sites such as silanol groups. This rearranged the molecular surface ESP of the demulsifier. As a result, the non-covalent interactions between demulsifier and water were greatly enhanced, leading to a significant reduction in the coalescence time of water droplets. This primary study on the size effects and non-covalent interactions of nano-demulsifiers will provide guidance for the design and development of highly efficient demulsifiers.

Exchange Coupling Effects on the Magnetotransport Properties of Ni-Nanoparticle-Decorated Graphene

We characterize the effect of ferromagnetic nickel nanoparticles (size ∼6 nm) on the magnetotransport properties of chemical-vapor-deposited (CVD) graphene. The nanoparticles were formed by thermal annealing of a thin Ni film evaporated on top of a graphene ribbon. The magnetoresistance was measured while sweeping the magnetic field at different temperatures, and compared against measurements performed on pristine graphene. Our results show that, in the presence of Ni nanoparticles, the usually observed zero-field peak of resistivity produced by weak localization is widely suppressed (by a factor of ∼3), most likely due to the reduction of the dephasing time as a consequence of the increase in magnetic scattering. On the other hand, the high-field magnetoresistance is amplified by the contribution of a large effective interaction field. The results are discussed in terms of a local exchange coupling, J∼6 meV, between the graphene π electrons and the 3d magnetic moment of nickel. Interestingly, this magnetic coupling does not affect the intrinsic transport parameters of graphene, such as the mobility and transport scattering rate, which remain the same with and without Ni nanoparticles, indicating that the changes in the magnetotransport properties have a purely magnetic origin.

Size Effects of Highly Dispersed Bismuth Nanoparticles on Electrocatalytic Reduction of Carbon Dioxide to Formic Acid.

Electrocatalytic reduction of carbon dioxide into value-added chemical fuels is a promising way to achieve carbon neutrality. Bismuth-based materials have been considered as favorable electrocatalysts for converting carbon dioxide to formic acid. Moreover, size-dependent catalysis offers significant advantages in catalyzed heterogeneous chemical processes. However, the size effects of bismuth nanoparticles on formic acid production have not been fully explored. Here, we prepared Bi nanoparticles uniformly supported on porous TiO2 substrate electrocatalytic materials by in situ segregation of the Bi element from Bi4Ti3O12. The Bi-TiO2 electrocatalyst with Bi nanoparticles of 2.83 nm displays a Faradaic efficiency of greater than 90% over a wide potential range of 400 mV. Theoretical calculations have also demonstrated subtle electronic structural evolutions induced by the size variations of Bi nanoparticles, where the 2.83 nm Bi nanoparticles display the most active p-band and d-band centers to guarantee high electroactivity toward CO2RR.

Metal particle size effects over the Ni/SAPO-11 bifunctional catalyst

The prominent size effects of metal nanoparticles (NPs) are mainly reflected in the change of electronic and geometric properties, which may induce distinct catalytic performance of the catalyst. Herein, Ni/SAPO-11 bifunctional catalysts with controllable sizes of Ni NPs were synthesized to investigate the particle size effects in n-hexane hydroisomerization. The results show that decreasing Ni particle size from 11.7 to 5.3 nm increases the concentration of surface Ni atoms and the proportion of low-coordinated Ni sites (corner, step sites) by 1.7 and 1.5 times, respectively. The low-coordinated surface Ni atoms have rich dangling bonds and high surface energy, resulting in greatly improved H2 adsorption and activation abilities. Moreover, an increased proportion of low-coordinated Ni sites within the Ni cluster shifts the d-band center upward, further enhancing the adsorption and activation of reactants. The intrinsic catalytic activity (turnover frequency) of 5.3 nm Ni NPs is ca. 2 times as much as that of the 11.7 nm ones. Besides, the smaller Ni NPs enhanced the metal–acid synergy, leading to a higher selectivity to isomers. This work provides deep insights into the metal particle size effects over the bifunctional Ni/SAPO-11 hydroisomerization catalysts and can be extended to various metal supported catalysts.

C, F co-doping Ag/TiO2 with visible light photocatalytic performance toward degrading Rhodamine B

The organic pollutants in industrial wastewater continuously endanger human health. Therefore, effective treatment of organic pollutants is very urgent. Photocatalytic degradation technology is an excellent solution to remove it. TiO2 photocatalysts are easy to prepare and have high catalytic activity, unfortunately, TiO2 only absorbs ultraviolet light limiting its utilization of visible light. In this study, a facile environmentally friendly synthesis of Ag-coated on micro-wrinkled TiO2-based catalysts in order to extend the absorption of Visible light. Firstly, a fluorinated titanium dioxide precursor was prepared by a one-step solvothermal method, and the precursor was calcined at high temperature in a nitrogen atmosphere to form a carbon dopant, and then a surface silver-deposited carbon/fluorine co-doped TiO2 photocatalyst C/F–Ag–TiO2 was prepared by a hydrothermal method The results showed that the Ag was coated on the wrinkled TiO2 layer and C/F–Ag–TiO2 photocatalyst was synthetized successfully. Benefit from the synergistic effect of doped carbon and fluorine atoms in combination with the quantum size effect of the surface silver nanoparticles, the band gap energy of C/F–Ag–TiO2 (2.56 eV) is obviously lower than anatase (3.2eV). The photocatalyst achieved an impressive degradation rate of 84.2% for Rhodamine B in 4 h, with a degradation rate constant of 0.367 h−1, which was 17 times higher than that of P25 under visible light. Therefore, the C/F–Ag–TiO2 composite is a promising candidate as a highly efficient photocatalyst for environmental remediation.

Size effect of fish gelatin nanoparticles on the mechanical properties of collagen film based on its hierarchical structure

Fish gelatin nanoparticles (FGNPs) of different sizes (∼155–410 nm) were successfully obtained by adjusting the ratio of gelatin and glutaraldehyde (Gel/Glu ratio), and their possible generation mechanisms were revealed by Fourier transform infrared (FTIR) analysis and transmission electron microscopy images. The FGNPs were then used to fabricate collagen composite films. Compared to a pure collagen film, the tensile strength, elongation at break, and Young's modulus of composite films increased by 37.1%, 34.4%, and 79.2%, respectively, while the water vapor permeability decreased by 51.5%. Meanwhile, scanning electron microscopy images, FTIR, and X-ray diffraction analysis suggested that small-sized and uniformly distributed FGNPs maintained the original crystal structure and well-arranged super helical structure of collagen, while large-sized and cross-linked FGNPs destabilized the collagen structure. A Gel/Glu ratio of 12:4 afforded FGNPs with a size of ∼155 nm, which was the best collagen composite film-forming size. Moreover, the FGNPs could bind to collagen through weak but countless non-covalent bonds (hydrogen bonds and ionic bonds), thereby improving the mechanical properties of the films. Overall, the FGNPs improved the performances characteristic of collagen films by influencing their structure, including hydrogen bonding interaction, crystalline structure, and superhelix structure, which would advance the understanding of collagen-based films.

Surface acoustic wave investigation of magnetic nanoparticle size and concentration effect on liquid crystal behavior.

The effect of spherical magnetic nanoparticles with different size (5, 10, 15, and 20 nm) and volume concentration (10-3, 5 × 10-4, and 10-4) on liquid crystal 4-cyano-4'-hexylbiphenyl (6CB) behavior was investigated using surface acoustic wave (SAW). The attenuation response of SAW propagating along with the substrate/liquid crystal interface was used to study the structural changes induced by an applied magnetic field. The obtained results showed the shift of the threshold magnetic field with an increase in the volume concentration of nanoparticles toward lower fields and also the decrease in the isotropic-nematic phase transition temperature depending on the nanoparticle size and the nanoparticle volume fraction. Results confirmed again that the bulk viscosity coefficients should dominate the SAW attenuation and that the SAW investigation in the presented configuration is applicable to monitoring of the role of magnetic dopants in structural changes under external fields. Some theoretical background of the presented SAW investigation is introduced as well. Obtained results are discussed within the context of previous ones.

Effects of Particle Size, Charge, Shape, Animal Disease State, and Sex on the Biodistribution of Intravenously Administered Nanoparticles

AbstractThe relationship between nanoparticle size, charge, shape, and in vivo biodistribution is of great importance for the rational design and selection of intravenously administered nanoparticles. A resource that aids in the selection and design of nanomaterials for this purpose would be a valuable tool. Previous literature reviews have examined narrow categories of nanomaterials or have not statistically analyzed a broad range of nanomaterial literature. Here, data regarding the biodistribution of intravenously administered synthetic and organic nanomaterials in animal models from literature available in PubMed is collected. This work outlines the effect of nanoparticle size, charge, shape, animal sex, and animal disease status on biodistribution of intravenously administered nanomaterials. Particle size and charge are found to significantly and independently influence biodistribution to several organs. Finally, animal sex and disease state are observed to function as effect modifiers for biodistribution.

Size Effect of Silver Nanoparticles Derived from Olive Mill Wastewater in THP-1 Cell Lines

The constant demand of silver nanoparticles (AgNPs) for different applications requires a new selection of solvents and reagents for their synthesis, to make them less toxic to living organisms and the environment. Among the alternative technologies that can be used to exclude the use of toxic products, green chemistry is based on the employment of biomolecules derived from plants or microorganisms to achieve NPs. Therefore, with the aim of applying the principles of circular economy, the waste deriving from the production of olive oil represents a useful source of polyphenols to be used as reduction agents to obtain AgNPs. In our work, we employed the Olive Mill Wastewater (OMWW), the so-called vegetation water typical of the Mediterranean geographical area, to achieve two sizes of AgNPs, i.e., 50 nm and 30 nm. These NPs were tested on the human monocytic cell line (THP-1) using two concentrations (3 µM and 5 µM) to understand their ability to trigger or not the inflammatory response. This was undertaken following IL-6, IL-8, IL-5 and TNF-α secretion and the NF-kB translocation. We concluded that the AgNPs did not induce strong activation of these pathways, especially when the cells were treated with higher dimensional NPs. Consequently, the application of these NPs in vivo for therapeutic purpose could be significant.

Designing flower-like MOFs-derived N-doped carbon nanotubes encapsulated magnetic NiCo composites with multi-heterointerfaces for efficient electromagnetic wave absorption

In order to acquire exceptional electromagnetic wave absorption properties, the microstructure design and component modification of composites are essential. Metal-organic frameworks (MOFs), due to the unique metal–organic crystalline coordination, tunable morphology, high surface area, and well-defined pores, have been regarded as promising electromagnetic wave absorption materials precursors. However, the inadequate contact abilities between adjacent MOFs nanoparticles endow it with undesirable electromagnetic wave dissipation capacity at a low filler loading, which is a great challenge to break size effect of nanoparticles to achieve efficient absorption. Herein, NiCo-MOFs derived N-doped carbon nanotubes encapsulated with NiCo nanoparticles anchored on flowers-like composites (denoted as NCNT/NiCo/C) were successfully prepared through facile hydrothermal method followed by thermal chemical vapor deposition with melamine-assisted catalyst. By controlling the Ni/Co ratio in precursor, the tunable morphology and microstructure of MOFs are achieved. Most importantly, the derived N-doped carbon nanotubes tightly connect the adjacent nanosheets to construct the special 3D interconnected conductive network, which effectively accelerates the charge transfer and improves the conduction loss. And notably, the NCNT/NiCo/C composite delivers excellent electromagnetic wave absorption performance with minimum reflection loss of −66.1 dB and wide effective absorption bandwidth up to 4.64 GHz when the Ni/Co ratio is 1:1. This work provides a novel method for the preparation of morphology controllable MOFs-derived composites and realizes high-performance electromagnetic wave absorption properties.

Combined effects of nanoparticle size, and nanoparticle and surfactant concentrations on the evaporative kinetics, dried morphologies, and plasmonic property of gold colloidal dispersion droplets

Understanding the combined influence of various parameters on the formation and morphologies of distinct solute deposit patterns obtained after droplet drying is essential for developing numerous real-time applications. In this work, gold nanoparticle (Au-NP) dispersion droplets are dried on a hydrophilic substrate and the coupled effects of nanoparticle size, and nanoparticle and surfactant (CTAB) concentrations on the evaporative kinetics and evaporation-induced nanoparticle assemblies in dried deposit patterns are studied using optical and scanning electron microscopy. The distinct stages of drying of a cetyltrimethylammonium bromide (CTAB) stabilized Au-NP dispersion droplet, such as the evolutions of pinning, depinning, and a depletion region, change drastically for a combined increase of CTAB concentration and nanoparticle size for different nanoparticle concentrations. Accordingly, the dried pattern is composed of distinct regions of closely bound ordered Au-NP assemblies coexisting with loosely bound disordered packings of Au-NPs that form inside and outside the coffee stain pattern. The multilayers of densely packed and hexagonally arranged Au-NPs at the outer coffee stain edge are tested for surface-enhanced Raman scattering activity against a standard probe molecule (Rhodamine B—RhB). The least detection limit of RhB at the outer coffee stain edge improves by three orders of magnitude with increasing nanoparticle concentrations and nanoparticle sizes. The present study demonstrates that the drying kinetics, distinct dried deposit morphologies, and the limit of plasmonic activity of the deposited Au-NPs can be fine-tuned via a combined variation of CTAB concentration, nanoparticle size, and nanoparticle concentration in the Au-NP dispersion droplet.

Pd-Nanoparticles-Catalyzed C(sp2)–H Arylation for the Synthesis of Functionalized Heterocycles: Recent Progress and Prospects

AbstractTransition-metal-nanoparticles-catalyzed C–H activation/functionalization is a prominent topic in contemporary research, enabling the functionalization of privileged heterocyclic scaffolds that hold a significant space in the scientific community due to their immense applications in materials science and in medicinal, natural product, and agricultural chemistry. Among transition-metal-based nanoparticles, Pd nanoparticle catalysis has emerged as the most attractive tool for promoting a wide array of practical synthetic transformations of heterocycles. In the last few years, the catalytic application of Pd nanoparticles in C–H functionalization has gained popularity in generating relatively inaccessible bonds with a high degree of selectivity and efficiency via the activation of surface metal atoms at the nanoscale level. The quantum size effect of nanoparticles offers a large surface area, with typically many easily accessible active sites/unit areas. These unique characteristics of nanoparticles are considered primary factors of enhanced catalytic activity compared to bulk materials. The nanoparticle catalysts anchored on solid-supports plus unsupported types (e.g., magnetic nanoparticles) allow easy separation from the reaction mixture, enabling recycling multiple times, which contributes notably to sustainable management and cost efficiency of a production process. In the current review, we discuss Pd-nanoparticles-catalyzed C(sp2)–H arylation for the synthesis of functionalized heterocycles, covering literature reports from 2010 to 2021. The preparation of Pd nanoparticles and the mechanistic realizations in their corresponding reactions are also explained briefly.1 Introduction2 Arylation of Heterocyclic Scaffolds2.1 Synthesis of Functionalized Indole Derivatives2.2 Synthesis of Functionalized (Benzo)thiazole/Benzoxazole Derivatives2.3 Synthesis of Functionalized Triazoles2.4 Synthesis of Functionalized Pyridines and Related Scaffolds2.5 Synthesis of Functionalized Furan, Thiophene and N-Methylpyrrole Scaffolds2.6 Synthesis of Functionalized Multiple Heterocycles via Single-Step Strategies3 Conclusions

Effect of nanoparticle size during discharging of NePCM in TTHE: A numerical investigation

The addition of nanoparticles is an effective strategy to upgrade the thermo-physical properties of phase change material. This paper concerns the effect of nanoparticle size on the discharging (solidification) of nanoparticles enhanced phase change material in triple-tube heat exchanger. The commercial tool Ansys Fluent is used to create the two-dimensional numerical model. For solidification, enthalpy-porosity has been adopted, while the change in properties of the material due to addition of nanoparticles is defined by the user defined function. The size of nanoparticles is varied as 20 nm, 30 nm and 40 nm during the analysis. The model has been validated against the reported result in the literature. The results from the transient numerical analysis shows that the total discharging time being shortened by around 25% and 40% for the phase change material with 30 nm and 40 nm size nanoparticles respectively compared to the phase change material with 20 nm size nanoparticles. It is observed that the drop of average temperature during the discharging process increases while increasing the size of nanoparticles in phase change material.

Nanoparticles size effect on transport properties of doped manganite elaborated by sol–gel route

Nanoparticles size effect on transport properties of doped manganite elaborated by sol–gel route

Experimental and Theoretical Studies of Different Parameters on the Thermal Conductivity of Nanofluids.

This work experimentally investigated the effects of different factors, including nanoparticle size and type, volume fraction, and base fluid, on the thermal conductivity enhancement of nanofluids. The experimental results indicate that the thermal conductivity enhancement of nanofluids is proportional to the thermal conductivity of the nanoparticles, with the enhancement being more pronounced for fluids with lower thermal conductivity. Meanwhile, the thermal conductivity of nanofluids decreases with increasing particle size and increases with increasing volume fraction. In addition, elongated particles are superior to spherical ones for thermal conductivity enhancement. This paper also proposes a thermal conductivity model by introducing the effect of nanoparticle size based on the previous classical thermal conductivity model via the method of dimensional analysis. This model analyzes the magnitude of influencing factors on the thermal conductivity of nanofluid and proposes suggestions for an improvement in thermal conductivity enhancement.

Size effect of ruthenium nanoparticles on water cracking properties with different crystal planes for boosting electrocatalytic hydrogen evolution

Small size ruthenium (Ru) nanoparticles have shown remarkable potential for electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the complicated preparation and relatively low activity of small size Ru nanoparticles are two key challenges. In this work, carbon nanotubes supported Ru nanoparticles catalysts (cnts@NC-Ru t °C) with different sizes were prepared via using the combination of L-3,4-dihydroxyphenylalanine (l-dopa) self-polymerization oxidation reaction and different high temperature annealing to study the variation of particle activity with size. Electrochemical test results showed that the optimized cnts@NC-Ru 700 °C catalyst exhibited a very low overpotential at 10 mA/cm2 (21 mV) and tafel slope of 34.93 mV/dec when the mass loading of precious metal per unit area was merely 12.11 μg/cm2 that surpassed most recently reported high-performance Ru based catalyst. The results of density functional theory (DFT) calculation showed that small Ru nanoparticles had abundant active sites, and the H2O dissociation on small Ru nanoparticles (110) surface is quite easy than other surfaces, while (111) surface of small Ru nanoparticles is beneficial for Tafel step of HER. The synergy between (110) and (111) surfaces on the Ru cluster contributes to its outstanding HER performance. This study provides a novel design idea in promoting the preparation method and uncovering the reason of high activity of small size Ru nanoparticles.