Size Distribution Of Nanoparticles Research Articles

Narrowing of band gap and decrease in dielectric loss in La1-xSrxMnO3 for x = 0.0, 0.1, and 0.2 manganite nanoparticles

Polycrystalline compounds of lanthanum strontium manganite (La1-xSrxMnO3, LSMO) are widely used in electronic storage devices due to their minimal losses and electronic charge transport properties. In this study, we investigated how varying substitutions of Sr2+ for values of x = 0.0, 0.1, and 0.2 affected the tuning of the optical band gap and dielectric losses in La1-xSrxMnO3 nanoparticles. Synthesized samples were structurally analyzed via X-ray diffraction. A rhombohedral R3¯c crystal structure was confirmed for all prepared samples; crystallite size ranging from 15 nm to 20 nm was estimated along with other lattice parameters. Polygonal or hexagonal-like morphology was revealed by field emission scanning electron microscopy, with a moderate size distribution of nanoparticles affected by thinner grain boundaries in doped LSMO. Energy dispersive spectroscopy was employed to confirm the elemental composition of each compound, and the infrared spectrum indicated bonding in the fingerprint region It was observed that there was a significant reduction in the optical band gap, which was measured using ultraviolet spectrometer absorption data. The band gap decreased from 4.34 eV to 4.11 eV. This reduction was found to be related to the difference in refractive index, which was calculated using both Moss and Herve–Vandamme relations. In parallel, frequency-dependent dielectric analysis revealed that frequency was proportional to the increase in Sr content, inversely affecting dielectric loss. Moreover, the AC conductivity of the prepared samples increased with the rise in Sr content, as described by Johnscher’s universal power law in the region of high frequency.

Valency of Ligand-Receptor Binding from Pair Potentials.

Coarse grained molecular dynamics simulations have been crucial for investigating the dynamics of nanoparticle uptake by cell membranes via ligand-receptor interactions. These models have enabled researchers to evaluate the effects of nanoparticle size, shape, and ligand distribution on cellular uptake. However, when pair potentials are used to represent ligand-receptor interactions, the number of receptors interacting with one ligand, valency, may vary. We demonstrate that the curvature of a nanoparticle, strength of ligand-receptor interactions, and ligand or receptor concentration change the valency, ranging from 3.4 to 5.1 in this study. Such a change in valency can create inaccurate comparisons between nanoparticles or even result in the uptake of smaller nanoparticles than would be expected. To rectify this inconsistency, we propose the adoption of a model based on bond formation and use it to determine the extent to which previous studies may have been affected. This work recommends avoiding pair potentials for modeling ligand-receptor interactions to ensure methodological consistency in nanoparticle studies.

Transmission electron microscopy reveals clusters of Au–Ag nanoparticles formed in TiO2 thin film, with enhanced plasmonic response

This work reports on the influence of nanoparticle (NP) size distribution and the chemical nature of gold (Au) and/or silver (Ag) NPs in the localized surface plasmon resonance (LSPR) responses. The NPs were produced embedded in a titanium dioxide (TiO2) thin film, deposited by reactive magnetron sputtering technique followed by in-vacuum thermal treatment at 400 °C. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) gave quantitative key information in terms of both the size and distribution of the noble metal NPs. The average Feret diameter was 17 nm (σ = 8) and 55 nm (σ = 28) for Au/TiO2 and Ag/TiO2 films, respectively, while the Au–Ag/TiO2 film showed intermediate values, with an average size of 22 nm (σ = 9). HAAD-STEM, complemented by EDX chemical mapping, revealed an unusual formation of cluster structures containing local distributions of bimetallic (alloyed) Au–Ag NPs. The synergetic characteristics and properties of such bimetallic Au–Ag NPs resulted in an outstanding LSPR sensitivity compared to the monometallic counterparts. Furthermore, the analysis of the average nearest neighbor distances (about one order of magnitude lower than counterparts) suggests the existence of plasmonic hotspots relevant to be explored in sensing and surface-enhanced spectroscopies.

Enhanced formic acid electro-oxidation reaction over Ir,N-doped TiO2-supported Pt nanocatalyst

In this work, we prepared an Ir,N-doped TiO2 nanomaterial via a facile HNO3-assisted hydrothermal process that was used as an advanced support for nano-sized Pt nanoparticles (NPs) for the formic acid oxidation reaction (FAOR). The physical and electrochemical behaviours of the as-made Pt/Ir,N-doped TiO2 catalyst were systemically investigated through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopes coupled with energy dispersive X-ray analysis (FE-SEM/EDX mapping), transmission electron microscopy (TEM), linear sweep voltammetry (LSV), Tafel slope, CO-stripping, and chronoamperometric (CA) test. The Pt NPs (ca. 3 nm) were anchored on the Ir,N-doped TiO2 support, being formed by a mixture of rutile and brookite with a particle size of several ten nanometers. Due to the small size and uniform distribution of Pt NPs, the Pt/Ir,N-doped TiO2 catalyst had an electrochemical surface area of 79.88 m2 g−1, which was greater than that of the commercial Pt/C (77.63 m2 g−1). In terms of the FAOR, the Pt/Ir,N-doped TiO2 catalyst showed a negative FAOR onset potential, high current density (11.85 mA cm−2), and superior CO-tolerance compared to the commercially available catalyst. Also, the as-made catalyst possessed high electrochemical durability after 3600 s for testing. The enhanced FAOR efficiency was assigned to the formation of a dual-doping effect and strong interplay between Pt and TiO2-based support, which not only improved the electron transfer but also weakened the adsorption of carbonaceous species, thereby boosting the reaction kinetics. This study could open up a facile but effective strategy to promote particular electrochemical applications.

Fabrication of highly sensitive memristive device using NiO nanoparticles synthesized by single step wet chemical method

Single step wet chemical method is used to prepare molar concentration varied NiO nanoparticle using PVP as the capping agent. Structural, optical and electrical properties are investigated on the prepared samples and are correlated with growth. TEM shows particle size distribution ∼ 3–4 nm synthesized in the range 0.001–1 M which agrees with XRD and optical measurements. Red shift in absorption is observed in optical measurement with enhancing molarity. Because of lesser size distribution of NiO nanoparticles, larger native defect in the form of oxygen vacancies is expected which may beutilized in fabrication of memristive devices. The sensitivity of the devices is estimated through Roff/Ron and area of pinched hysteresis loopwhich shows promising result. Higher sensitivity is explained due to incorporation of more oxygen vacancies during the growth of NiO nanoparticles synthesized at higher concentration. The experimental memristive characteristics are validated through theoretical model fitting using different window functions.

Efficient and Sustainable Synthesis of Zinc Salt-Dependent Polycrystal Zinc Oxide Nanoparticles: Comprehensive Assessment of Physicochemical and Functional Properties

This research involved synthesizing zinc salt-dependent zinc oxide nanoparticles (ZS-ZnO-NPs) using different zinc salts (ZnCl2, ZnSO4·H2O, Zn(CH3COO)2·2H2O, and Zn(NO3)2·6H2O) and plant extracts of Phoenix dactylifera L. The synthesis efficiency was evaluated, and to carry out further investigations, zeta potential measurements, as well as SEM and TEM examinations, were performed to assess the morphology and size distribution of the nanoparticles. XRD and UV-Vis spectroscopy were also employed to confirm the crystalline nature and optical properties of the synthesized ZS-ZnO-NPs, respectively. FTIR analysis was also performed to identify chemical groups on the nanoparticle surface. Furthermore, the ZS-ZnO-NPs’ ability to scavenge free radicals (FRs●), and thus their antioxidant capacity, was assessed using the DPPH FR● assay. The results showed that the type of zinc salt used for the synthesis significantly influenced the yield, stability, optical properties, morphology, and size distribution of nanoparticles. The zinc salt-dependent yield exhibited a notable range, varying from 50.3% to 55.3%. The nanoparticle size ranged from 3.7 to 10.2 nm, with the zeta potential ranging from −28.6 to −46.7 mV and the gap energy (Eg) ranging from 3.28 to 3.39 eV. Moreover, the synthesized ZS-ZnO-NPs exhibited concentration and time-dependent inhibitory activity against DPPH FR●, showing potential as antioxidant agents in biomedicine and other industries.

Synthesis of AuNPs in microemulsion and nano-emulsion systems using aqueous extract of C. chayamansa leaves as reducing agent

This paper explores the synthesis and characterization of gold nanoparticles using various microemulsion and nano-emulsion systems. The pseudo-ternary system consists of an aqueous phase / Brij O10: 1,2-hexanediol (1:1) / castor oil; the aqueous phases include the aqueous extract of Chaya Maya (Cnidoscolus chayamansa) leaves or aqueous extract of Chaya maya leaves combined with the inorganic gold precursor. Chaya maya extract act as a reducing agent for gold (III) ions. The influence of aqueous phase content and surfactant concentration on gold nanoparticles size, morphology, and stability is investigated. Dynamic Light Scattering, Scanning Transmission Electron Microscopy, and UV-Vis spectroscopy are employed to analyze the synthesized gold nanoparticles. The sizes of the gold nanoparticles obtained were influenced by the system composition and are within the range of 19–40 nm. Results indicate that increasing the aqueous phase content generally leads to larger nanoparticle sizes, while higher surfactant concentrations yield smaller nanoparticles. A transition from microemulsion to nano-emulsion is observed at a specific aqueous phase content, marking a shift in nanoparticle size distribution and growth behavior. Additionally, microemulsion and nano-emulsion systems provide stability to gold nanoparticles, as evidenced by measured Zeta potentials indicating negatively charged surfaces conducting to colloidal stability. Also, remark that the use of organometallic precursors is no needed to obtain very good results on nanoparticle size and shape when O/W systems are used to this end. These findings highlight the potential of tailored microemulsion and nano-emulsion systems formulated with low-toxic components for controlling gold nanoparticles properties under mild conditions, contributing to the development of advanced gold nanoparticles-based materials with enhanced functionalities, with implications for diverse applications.

Effect of Biodegradable Mifepristone Drug Delivery System on the Ultrastructure and Angiogenesis Related Factors of Adenomyosis Cells

The aim of this research aimed to analyze the effects of degradable mifepristone nano-drug delivery system (DDS) on the ultrastructure, proliferation, apoptosis, and angiogenesis of adenomyosis cells. Drug-loaded nanoparticles (DNPs) of poly lactic-co-glycolic acid (PLGA) were prepared. The particle size distribution and surface Zeta potential (SZP) of nanoparticles (NPs) were detected. The morphology of NPS was subjected to observation by transmission electron microscope (TEM). Adenomyosis lesion cells were cultured by tissue digestion method, and the cell morphology was observed and identified. The cells were divided into blank control (NC), mifepristone, and mifepristone/PLGA groups. The cell proliferation, ultrastructure, apoptosis, and the expression of Survivin, VEGFR1, and VEGFR2 were detected by MTT, TEM, flow cytometry (FC), and immuno-histochemistry, respectively. The results suggested that the average particle size of mifepristone/PLGA NPs was (185.6±12.9) nm, and the SZP was (−9.5±0.9) mV. It presented the characteristics of circularity, uniform distribution, and smooth surface under TEM. As against the raw drug mifepristone, the release time of mifepristone/PLGA NPs was prolonged, and the drug release rate reached 87.4% at 72 h. As against NC, the cell proliferation rate (CPR) was clearly decreased, the apoptosis rate (AR) was increased, and Survivin, VEGFR1, and VEGFR2 had a decrease in mifepristone and mifepristone/PLGA groups (P <0.05). As against mifepristone group, the CPR was clearly decreased, the AR was increased, and Survivin, VEGFR1, and VEGFR2 had a decrease in mifepristone/PLGA group (P <0.05). In conclusion, mifepristone PLGA DNPs were able to delay drug release. Mifepristone can inhibit angiogenesis and promote apoptosis of adenomyosis by affecting the expression of Survivin, VEGFR1, and VEGFR2, thus playing a role in the treatment of adenomyosis.

In Situ Monitoring of Non-Thermal Plasma Cleaning of Surfactant Encapsulated Nanoparticles

Surfactants are widely used in the synthesis of nanoparticles, as they have a remarkable ability to direct their growth to obtain well-defined shapes and sizes. However, their post-synthesis removal is a challenge, and the methods used often result in morphological changes that defeat the purpose of the initial controlled growth. Moreover, after the removal of surfactants, the highly active surfaces of nanomaterials may undergo structural reconstruction by exposure to a different environment. Thus, ex situ characterization after air exposure may not reflect the effect of the cleaning methods. Here, combining X-ray photoelectron spectroscopy, in situ infrared reflection absorption spectroscopy, and environmental transmission electron microscopy measurements with CO probe experiments, we investigated different surfactant-removal methods to produce clean metallic Pt nanoparticles from surfactant-encapsulated ones. It was demonstrated that both ultraviolet-ozone (UV-ozone) treatment and room temperature O2 plasma treatment led to the formation of Pt oxides on the surface after the removal of the surfactant. On the other hand, when H2 was used for plasma treatment, both the Pt0 oxidation state and nanoparticle size distribution were preserved. In addition, H2 plasma treatment can reduce Pt oxides after O2-based treatments, resulting in metallic nanoparticles with clean surfaces. These findings provide a better understanding of the various options for surfactant removal from metal nanoparticles and point toward non-thermal plasmas as the best route if the integrity of the nanoparticle needs to be preserved.

Detection of NH3 gas using CrVO4 nanoparticles

Nanostructured chromium orthovanadate with an average particle size of 65 nm was prepared by the co-precipitation technique for the chemiresistive sensor. The morphology and particle size distribution of CrVO4 nanoparticles were examined by SEM and TEM. According to XRD, most of the prepared CrVO4 material (crystallites) has a monoclinic structure belonging to the space group C2/m. XPS and UV-Vis absorbance measurements provided additional information on the main phase and the surface. The material has shown reasonable selectivity towards the NH3 gas. The as-prepared CrVO4 nanostructures exhibit a maximum relative response of 32% to 50 ppm NH3. The identical dynamic response profiles during the sequential injections of 50 ppm NH3 evinced the repeatability of the sensor. The limit of detection (LOD) value of the sensor was estimated ca 0.7 ppm using relative response values towards a wide range of NH3 concentrations from 10 ppm to 100 ppm. The sensing mechanism was expressed in terms of the surface band bending phenomenon caused by the adsorption and desorption of the ammonia. The best sensor performance was achieved at 330 °C, where the effects of humidity and moisture can be neglected. The results confirmed that the CrVO4 nanomaterial has the potential to fabricate an affordable, easy-to-make, and reliable gas sensor for NH3 gas.

Biomass substrate-derived graphene-like N-doped porous carbon nanosheet-supported PtCo nanocatalyst for efficient and selective hydrogenation of unsaturated furanic aldehydes

Unsaturated furanic aldehydes are derived from lignocellulosic biomass resources and subsequently used to produce valuable chemicals. However, the highly efficient, selective hydrogenation of the biomass-derived unsaturated furan CO bond remains challenging. Here we report that graphene-like nitrogen doped porous carbon (GNPC) nanosheets are synthesized from carbon-rich, sustainable, and renewable biomass precursors (glucose, fructose and 5-hydroxymethylfurfural, HMF) with high surface areas, large pore volumes and narrow mesopores. GNPC derived from HMF is an excellent catalyst support for PtCo nanoparticles with ultrafine nanoparticles size and homogeneous distributions. This catalyst is highly efficient for hydrogenation of biomass-derived furan-based unsaturated aldehydes, with high yields, to the corresponding unsaturated alcohols under mild conditions. This design strategy should further allow the development of selective, simple, green heterogeneous catalysts for challenging chemical transformations.

Toward the Scalable, Rapid, Reproducible, and Cost-Effective Synthesis of Personalized Nanomedicines at the Point of Care.

Organic nanoparticles are used in nanomedicine, including for cancer treatment and some types of COVID-19 vaccines. Here, we demonstrate the scalable, rapid, reproducible, and cost-effective synthesis of three model organic nanoparticle formulations relevant to nanomedicine applications. We employed a custom-made, low-cost fluid mixer device constructed from a commercially available three-dimensional printer. We investigated how systematically changing aqueous and organic volumetric flow rate ratios determined liposome, polymer nanoparticle, and solid lipid nanoparticle sizes, size distributions, and payload encapsulation efficiencies. By manipulating inlet volumes, we synthesized organic nanoparticles with encapsulation efficiencies approaching 100% for RNA-based payloads. The synthesized organic nanoparticles were safe and effective at the cell culture level, as demonstrated by various assays. Such cost-effective synthesis approaches could potentially increase the accessibility to clinically relevant organic nanoparticle formulations for personalized nanomedicine applications at the point of care, especially in nonhospital and low-resource settings.

Exosome-like genistein-loaded nanoparticles developed by thin-film hydration and 3D-printed Tesla microfluidic chip: A comparative study

Exosomes are naturally derived information carriers that present interest as drug delivery systems. However, their vague cargo and isolation difficulties hinder their use in clinical practice. To overcome these limitations, we developed exosome-like nanoparticles, consisted of the main lipids of exosomes, using two distinct methods: thin-film hydration and 3D-printed microfluidics. Our novel microfluidic device, fabricated through digital light processing printing, demonstrated a favorable architecture to produce exosome-like nanoparticles. We compared these two techniques by analyzing the physicochemical characteristics (size, size distribution, and ζ-potential) of both unloaded and genistein-loaded exosome-like nanoparticles, using dynamic and electrophoretic light scattering. Our findings revealed that the presence of small lipophilic molecules, cholesterol and/or genistein, influenced the characteristics of the final formulations differently based on the development approach. Regardless of the initial differences of the formulations, all exosome-like nanoparticles, whether loaded with genistein or not, exhibited remarkable colloidal stability over time. Furthermore, an encapsulation efficiency of over 87% for genistein was achieved in all cases. Additionally, thermal analysis uncovered the presence of metastable phases within the membranes, which could impact the drug delivery efficiency. In summary, this study provides a comprehensive comparison between conventional and innovative methods for producing complex liposomal nanosystems, exemplified by exosome-like nanoparticles.

Microfluidic synthesis of lipid-based nanoparticles for drug delivery: recent advances and opportunities.

Microfluidic technologies are revolutionizing the synthesis of nanoscale lipid particles and enabling new opportunities for the production of lipid-based nanomedicines. By harnessing the benefits of microfluidics for controlling diffusive and advective transport within microfabricated flow cells, microfluidic platforms enable unique capabilities for lipid nanoparticle synthesis with precise and tunable control over nanoparticle properties. Here we present an assessment of the current state of microfluidic technologies for lipid-based nanoparticle and nanomedicine production. Microfluidic techniques are discussed in the context of conventional production methods, with an emphasis on the capabilities of microfluidic systems for controlling nanoparticle size and size distribution. Challenges and opportunities associated with the scaling of manufacturing throughput are discussed, together with an overview of emerging microfluidic methods for lipid nanomedicine post-processing. The impact of additive manufacturing on current and future microfluidic platforms is also considered.

Nanoparticle Size Distribution and Stability Assessment Using Asymmetric-Flow Field-Flow Fractionation.

Nanomaterials are inherently polydisperse. Traditional techniques, such as the widely used batch-mode dynamic light-scattering (DLS) analysis, are not ideal nor thoroughly descriptive enough to define the full complexity of these materials. Asymmetric-flow field-flow fractionation (AF4) with various in-line detectors, such as ultraviolet-visible (UV-vis), multi-angle light scattering (MALS), refractive index (RI), and DLS, is an alternative technique that can provide flow-mode analysis of not only size distribution but also shape, drug release/stability, and protein binding.

Predicting environmental concentrations of nanomaterials for exposure assessment - a review

There have been major advances in the science to predict the likely environmental concentrations of nanomaterials, which is a key component of exposure and subsequent risk assessment. Considerable progress has been since the first Material Flow Analyses (MFAs) in 2008, which were based on very limited information, to more refined current tools that take into account engineered nanoparticle (ENP) size distribution, form, dynamic release, and better-informed release factors. These MFAs provide input for all environmental fate models (EFMs), that generate estimates of particle flows and concentrations in various environmental compartments. While MFA models provide valuable information on the magnitude of ENP release, they do not account for fate processes, such as homo- and heteroaggregation, transformations, dissolution, or corona formation. EFMs account for these processes in differing degrees. EFMs can be divided into multimedia compartment models (e.g., atmosphere, waterbodies and their sediments, soils in various landuses), of which there are currently a handful with varying degrees of complexity and process representation, and spatially-resolved watershed models which focus on the water and sediment compartments. Multimedia models have particular applications for considering predicted environmental concentrations (PECs) in particular regions, or for developing generic “fate factors” (i.e., overall persistence in a given compartment) for life-cycle assessment. Watershed models can track transport and eventual fate of emissions into a flowing river, from multiple sources along the waterway course, providing spatially and temporally resolved PECs. Both types of EFMs can be run with either continuous sources of emissions and environmental conditions, or with dynamic emissions (e.g., temporally varying for example as a new nanomaterial is introduced to the market, or with seasonal applications), to better understand the situations that may lead to peak PECs that are more likely to result in exceedance of a toxicological threshold. In addition, bioaccumulation models have been developed to predict the internal concentrations that may accumulate in exposed organisms, based on the PECs from EFMs. The main challenge for MFA and EFMs is a full validation against observed data. To date there have been no field studies that can provide the kind of dataset(s) needed for a true validation of the PECs. While EFMs have been evaluated against a few observations in a small number of locations, with results that indicate they are in the right order of magnitude, there is a great need for field data. Another major challenge is the input data for the MFAs, which depend on market data to estimate the production of ENPs. The current information has major gaps and large uncertainties. There is also a lack of robust analytical techniques for quantifying ENP properties in complex matrices; machine learning may be able to fill this gap. Nevertheless, there has been major progress in the tools for generating PECs. With the emergence of nano- and microplastics as a leading environmental concern, some EFMs have been adapted to these materials. However, caution is needed, since most nano- and microplastics are not engineered, therefore their characteristics are difficult to generalize, and there are new fate and transport processes to consider.

Green Synthesis Silver Nanoparticles Using Sembung (Blumea balsamifera) Leaf Extract as an Antibacterial and Antioxidant

Silver Nanoparticles essentially focuses on the synthesis of nano-sized particles produced through chemical, physical and biological processes, which contribute significantly to the control of plant and animal diseases and have shown considerable promise in improving the quality of living conditions and human health. Currently, silver nanoparticles (AgNP) have shown their potential as an alternative antibacterial and antioxidant agent in many studies. The method for making silver nanoparticles, namely Green synthesis, involves the use of plants for the synthesis process of various types of nanoparticles. Green synthesis has the advantages, namely that the method is simple, environmentally friendly, non-polluting, antitoxic and cost-effective. The aim of this research is to determine the antibacterial and antioxidant activity of AgNPs. In this research, the nanoparticle solution was visually determined by the yellow-brown color change. In the spectrophotometer absorption spectrum appears at a wavelength of 425 nm. The results of determining the size distribution of silver nanoparticles using PSA show that the particle size distribution obtained has an average value of 40.5 nm and 59.6 nm for silver nanoparticles for AgNO3 concentrations of 1 mM and 2 mM, respectively. FTIR measurements are used to determine the presence of bioactive molecules that may be responsible for the stabilization that acts as a capping agent. Absorption spiked at 3.280; 2.919; 1.583; 1.379; 1.239 and 1.068 cm−1 were determined for sembung leaf extract, while silver nanoparticles showed an absorption spike at 3.368; 2.850; 1.594; 1.369; 1.244 and 1.108 cm−1. The results of XRD analysis of AgNP show that it has been successfully synthesized which can be seen from the formation of a narrow peak indicating the crystalline nature of the nanoparticles formed. The results of TEM analysis of AgNPs in this study are mixed shapes such as spherical, hexagonal and triangular shapes of silver nanoparticles. The antibacterial activity test of silver nanoparticles with sembung leaf extract with varying concentrations of AgNO3 solution was successful as indicated by the formation of an inhibition zone for Eschericia coli and Staphylococcus aureus bacteria. The results show that the antioxidant activity of AgNPs shows that the percentage of inhibition increases as the concentration of AgNPs increases from 100 to 500 ppm and ascorbic acid increases from 1 to 5 ppm.

How Nanoparticle Size and Bubble Merging Is Governed by Short‐Range Spatially Controlled Double‐Beam Laser Ablation in Liquids

AbstractPulsed laser ablation in liquid (LAL) is a method for synthesizing nanoparticles with controlled composition and high purity. However, current research predominantly examines isolated cavitation bubbles, overlooking real‐world LAL scenarios where numerous bubbles interact simultaneously. This study addresses this gap by investigating the effects of short‐range micrometric spatially controlled double‐pulse laser ablation in liquids on nanoparticle size distribution. Gold and YAG are used as model materials, and a dimensionless parameter, H*, is introduced to quantify the ratio between double bubble spatial separation and their maximum height. This parameter correlates with cavitation bubble merging time, bubble volume change rate, and subsequent nanoparticle size increase. Shadowgraphs provide valuable insights into bubble contact and fusion dynamics, showcasing phase separation by a thin water film and subsequent merging into a single bubble. Notably, a twofold increase in nanoparticle size is observed for both Au and YAG at H* = 0.25. The research indicates a strong association between nanoparticle size trends and cavitation bubble volume rate change, particularly emphasized at H* = 0.25. Understanding the dynamics of neighboring bubbles during LAL emphasizes the relevance of lateral pulse distances in dual‐beam LAL, impacting particle size distribution in a distance‐dependent manner.

Dilution versus fractionation: Separation technologies hyphenated with spICP-MS for characterizing metallic nanoparticles in aerosols

The presence of metal salts has become one of the major limitations for measuring metallic nanoparticles (NPs) in single particle inductively coupled plasma mass spectrometry (spICP-MS). Their presence generates a background signal in spICP-MS that can be overlapped with the signal intensity of small particles, leading to inaccurate NP size distributions. To overcome this analytical problem, sample pretreatment methods (e.g. dilution or fractionation) have been applied to liquid samples before spICP-MS measurements to minimize the ionic interference. However, the number of studies focused on reducing the presence of metal salts in aerosol characterization is limited. In this contribution, we investigated three different technologies coupled to an ICP-MS for online separating metallic NPs signals from ionic interference signals of metal salts in the aerosol. A rotating disk diluter (RDD) was used for the online dilution of the aerosol, while a differential mobility analyzer (DMA) and a centrifugal particle mass analyzer (CPMA) were used for the online fractionation of specific-sized NPs in the aerosol. The results from the analysis of 100 nm gold NPs (AuNPs) mixed with gold salts (Au3+, mass ratio 1:25) showed the particle size limit of detection decreased from 78 nm to 61, 50, and 33 nm by using RDD, CPMA, and DMA respectively. In addition, it was found that the separation performance of AuNPs was in the order of DMA > RDD > CPMA. The methods used in this study based on spICP-MS have the potential to characterize directly NPs in complex aerosols containing metal salts.

Exploring nanoparticle emissions and size distributions during incense burning and filtration in an indoor space

Exploring nanoparticle emissions and size distributions during incense burning and filtration in an indoor space