A5027911061- Nanoparticles: synthesis and applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanocluster Synthesis and Applications
- Advanced Nanomaterials in Catalysis
- Nanoparticle-Based Drug Delivery
- Air Quality and Health Impacts
- Field-Flow Fractionation Techniques
- Graphene and Nanomaterials Applications
- Electrochemical Analysis and Applications
- Nanomaterials for catalytic reactions
- Microplastics and Plastic Pollution
- Biosensors and Analytical Detection
- Catalytic Processes in Materials Science
- Healthcare and Environmental Waste Management
- Quantum Dots Synthesis And Properties
- Iron oxide chemistry and applications
- Analytical chemistry methods development
- Gas Sensing Nanomaterials and Sensors
- Advanced biosensing and bioanalysis techniques
- Dendrimers and Hyperbranched Polymers
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Sensor Technologies
- Heavy metals in environment
- Heavy Metal Exposure and Toxicity
- Advanced Materials Characterization Techniques
Material Measurement Laboratory
2012-2023
National Institute of Standards and Technology
2012-2023
National Institute of Standards
2014-2023
University of Iowa
2006-2012
Biochemical Society
2006
Nanotechnology offers great promise in many industrial applications. However, little is known about the health effects of manufactured nanoparticles, building blocks nanomaterials.Titanium dioxide (TiO(2)) nanoparticles with a primary size 2-5 nm have not been studied previously inhalation exposure models and represent some smallest nanoparticles. The purpose this study was to assess toxicity these using murine model lung inflammation injury.The properties TiO(2) as well characteristics...
In this study, the adsorption of two organic acids, oxalic acid and adipic acid, on TiO2 nanoparticles was investigated at room temperature, 298 K. Solution-phase measurements were used to quantify extent reversibility anatase with primary particle sizes 5 32 nm. At all pH values considered, there minimal differences in measured Langmuir constants, Kads, or surface-area-normalized maximum adsorbate−surface coverages, Γmax, between nm particles. Although macroscopic reactivity these acids as...
Copper nanomaterials are being used in a large number of commercial products because these materials exhibit unique optical, magnetic, and electronic properties. Metallic copper nanoparticles, which often have thin surface oxide layer, can age the ambient environment become even more oxidized over time. These aged nanoparticles will then different properties compared to original nanoparticles. In this study, we characterized three types copper-based nanoparticle (NP) samples designated as...
Triphenylphosphine (PPh3) is commonly used during syntheses of stable, closed-shell monolayer protected clusters (MPCs). Models transition metal (TM) cluster and nanoparticle assign PPh3 a passive role as chemical placeholder, electron balancing species, or surfactant. This study provides the first direct evidence that proactive etching agent promotes formation specific sizes. To observe this effect, we developed colorimetric tool simultaneously monitors size distribution population...
Transmission FTIR spectroscopy and X-ray photoelectron (XPS) are used to probe the details of sulfur dioxide adsorption photooxidation on titanium nanoparticle surfaces. Adsorption sites, surface speciation chemistry have been determined from analysis spectra in conjunction with isotope labeling experiments. These data show that hydroxyl groups involved dioxide, particularly, reacts either one O–H group yield adsorbed bisulfite or two sulfite water. Using 16O–H, 16O–D 18O–H labeled groups,...
Although recent evidence suggests that particle size plays an important role in the dissolution of iron from mineral dust aerosol, a fundamental understanding how influences rate and extent oxide processes remains unclear. In this study, surface spectroscopic methods are combined with solution phase measurements to explore ligand-promoted photochemical reductive goethite (α-FeOOH) different sizes presence oxalate at pH 3 298 K. Both X-ray photoelectron spectroscopy attenuated total...
TiO2 is a widely used manufactured nanomaterial and the opportunity for human exposure makes it necessary to study its health implications. Using murine models inflammation, size effects of inflammatory response in instillation acute inhalation exposures nanoparticles with manufacturers' average particles sizes 5 21 nm were investigated. The properties primary nanoparticles, nanoparticle agglomerates aerosol solution both sized evaluated. Mice acutely exposed whole-body chamber or through...
We examined pulmonary inflammatory responses of mice following whole-body inhalation exposure to copper and iron nanoparticles in acute sub-acute studies. Concentrations for exposures were 3.6 mg m−3. No significant pathology was found exposure. Immediately exposure, both iron- copper-exposed showed increased inflammation compared sentinels. Copper nanoparticle-exposed had significantly higher lavage cytokines as well perivasculitis alveolitis. Three weeks post-exposure, all markers...
We report a new strategy that provides stringent control for the size and dispersity of ultrasmall nanoclusters through preparation gold complex distributions formed from precursor, AuClPPh3 (PPh3 = triphenylphosphine), L6 (L6 1,6-bis(diphenylphosphino) hexane) ligand prior to reduction with NaBH4 in 1:1 methanol/chloroform solutions. Monodisperse distinct nuclearity are obtained specific ratios; [L6]/[PPh3] 4 yields [Au8L64]2+, 0.4 [Au9L64Cl]2+, 8 ligated Au10 cores form [Au10L64]2+...
Bridging knowledge gaps in NanoEHS by identifying current fundamental science challenges and research needs.
This report outlines the determination of a reaction mechanism that can be manipulated to develop directed syntheses gold monolayer-protected clusters (MPCs) prepared by reduction solutions containing 1,3-bis(diphenylphosphino)propane (L3) ligand and Au(PPh3)Cl. Nanocluster synthesis was initiated two-coordinate phosphine-ligated [AuILL′]+ complexes (L, L′ = PPh3, L3), resulting in free radical complexes. The [Au0LL′]• radicals nucleated, forming broad size distribution ligated clusters....
A limiting factor in assessing the risk of current and emerging nanomaterials biological environmental systems is ability to accurately detect characterize their size, shape, composition broad product distributions complex media. Asymmetric flow field-flow fractionation (A4F) capable separation without stationary phase interactions or large applied forces. Here, we demonstrate unprecedented A4F metallic nanoclusters with core diameters near 1 nm high resolution. The isolated nanocluster...
Cisplatin-complexed gold nanoparticles (PtII-AuNP) provide a promising strategy for chemo-radiation-based anticancer drugs. Effective design of such platforms necessitates reliable assessment surface engineering on quantitative basis and its influence drug payload, stability, release. In this paper, poly(ethylene glycol) (PEG)-stabilized PtII-AuNP was synthesized as model antitumor platform, where PtII is attached via carboxyl-terminated dendron ligand. Surface modification by PEG loading,...
The transport and chemical identification of microplastics nanoplastics (MNPs) are critical to the concerns over plastic accumulation in environment. Chemically physically transient MNP species present unique challenges for isolation analysis due many factors such as their size, color, surface properties, morphology, potential change. These contribute eventual environmental toxicological impact MNPs. As analytical methods instrumentation continue be developed this application, test materials...
Determining unknown secondary micro and nanoplastic (MNP) composition remains a persistent analytical challenge for field collected samples. The availability of material standards should accelerate method development improved identification. Here,...
Abstract The formation of ligand‐protected gold nanoclusters during size‐selective syntheses is seemingly driven by the inherent properties protecting ligands, but a general description product has not been presented. This study uses diphosphine‐protected Au clusters as model system to examine i) control metal‐ligand complex distributions in methanol–chloroform solutions, ii) role solution perturbations, e.g., oxidation, and iii) nanocluster through reduction characterized distributions. By...
We identify the reaction network governing gold monolayer protected cluster (MPC) formation during reduction of Au(PPh3)Cl and L5 (L5 = 1,5-bis(diphenylphosphino)pentane) in solutions. UV-vis spectroscopy electrospray ionization mass spectrometry (ESI-MS) monitored ligated Aux: 6 ≤ x 12 clusters, which comprise intermediates final products. Initially, predominantly [Au2L52]2+ complexes form through dissolution Au(PPh3)Cl. These control nucleation reactions that nascent phosphine-ligated Au8...
To probe the transformation pathways of metallic nanomaterials, measurement tools capable detecting and characterizing broad distribution products with limited perturbation are required. Here, we demonstrate detection resulting from 40 kDa PVP-coated silver nanoparticles (AgNPs) reacted in aerated, sulfide-containing water EPA moderately hard reconstituted standard. Using single particle inductively coupled plasma mass spectrometry, preservation primary AgNP populations during sulfidation...
An electrospray-differential mobility analyzer (ES-DMA) was operated with an aerosol flow-mode, temperature-programmed approach to enhance its ability characterize the particle size distributions (PSDs) of nanoscale particles (NPs) in presence adsorbed and free ligands. Titanium dioxide NPs (TiO2-NPs) stabilized by citric acid (CA) or bovine serum albumin (BSA) were utilized as representative systems. Transmission electron microscopy (TEM) inductively coupled plasma mass spectrometry used...
Cationic polyethylenimine conjugated gold nanoparticles (AuNP-PEI) are a widely studied vector for drug delivery and an effective probe interrogating NP-cell interactions. However, inconsistent body of literature currently exists regarding the reproducibility physicochemical properties, colloidal stability, efficacy these species. To address this gap, we systematically examined preparation, formation mechanism PEI conjugates produced from citrate-capped AuNPs. We considered dependence on...
Elucidating the polyethyleneimine (PEI) chemistry to predictively and reproducibly synthesize gold nanoparticle (AuNP)-PEI conjugates with desired properties has been elusive despite evaluation in numerous studies reported enhanced properties. The lack of reproducible methods control core size stability led contradictory results for performance safety; thus, advancement conjugate platform commercial use likely hindered. Recently, we a robust, method synthesizing PEI-functionalized AuNPs...
Reported reaction kinetics of metal nanoparticles in natural and engineered systems commonly have used proxy measurements to infer chemical transformations, but extension these methods complex media has proven difficult.