title: Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis.
abstract: For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the organism and/or suspended in the dispersion following exposure. Here, we measure the uptake of 30 and 60 nm gold nanoparticles (AuNPs) by the nematode, Caenorhabditis elegans, using a sucrose density gradient centrifugation protocol to remove noningested AuNPs. Both conventional inductively coupled plasma mass spectrometry (ICP-MS) and single particle (sp)ICP-MS are utilized to measure the total mass and size distribution, respectively, of ingested AuNPs. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) imaging confirmed that traditional nematode washing procedures were ineffective at removing excess suspended and/or adsorbed AuNPs after exposure. Water rinsing procedures had AuNP removal efficiencies ranging from 57 to 97% and 22 to 83%, while the sucrose density gradient procedure had removal efficiencies of 100 and 93 to 98%, respectively, for the 30 and 60 nm AuNP exposure conditions. Quantification of total Au uptake was performed following acidic digestion of nonexposed and Au-exposed nematodes, whereas an alkaline digestion procedure was optimized for the liberation of ingested AuNPs for spICP-MS characterization. Size distributions and particle number concentrations were determined for AuNPs ingested by nematodes with corresponding confirmation of nematode uptake via high-pressure freezing/freeze substitution resin preparation and large-area SEM imaging. Methods for the separation and in vivo quantification of ENPs in multicellular organisms will facilitate robust studies of ENP uptake, biotransformation, and hazard assessment in the environment.
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Monique E
authors.identifier: 0000-0001-5096-2003
authors.initials: ME
authors.lastname: Johnson
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Shannon K
authors.initials: SK
authors.lastname: Hanna
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Antonio R
authors.initials: AR
authors.lastname: Montoro Bustos
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Sims
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Lindsay C C
authors.initials: LC
authors.lastname: Elliott
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Akshay
authors.initials: A
authors.lastname: Lingayat
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Johnston
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Babak
authors.initials: B
authors.lastname: Nikoobakht
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: John T
authors.initials: JT
authors.lastname: Elliott
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: R David
authors.initials: RD
authors.lastname: Holbrook
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Keana C K
authors.initials: KC
authors.lastname: Scott
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Murphy
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Elijah J
authors.initials: EJ
authors.lastname: Petersen
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Lee L
authors.initials: LL
authors.lastname: Yu
authors.affiliation: Chemical Science Division, ‡Biosystems and Biomaterials Division, and §Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Bryant C
authors.initials: BC
authors.lastname: Nelson
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry*; D002499:Centrifugation, Density Gradient; D006046:Gold / Q000737:chemistry / Q000302:isolation & purification*; D013058:Mass Spectrometry; D053768:Metal Nanoparticles / Q000737:chemistry*; D061848:Optical Imaging; D010316:Particle Size; D013395:Sucrose / Q000737:chemistry; D013499:Surface Properties
chemical_list: D013395:Sucrose; D006046:Gold
keywords: Caenorhabditis elegans; gold nanoparticles; nanotoxicity; single particle ICP-MS; sucrose density gradient separation; uptake