Synthesis and Characterization of Polyvinylpyrrolidone Coated Cerium Oxide Nanoparticles

Abstract

There is a pressing need for the development of standard and reference nanomaterials for environmental nanoscience and nanotoxicology. To that aim, suspensions of polyvinylpyrrolidone (PVP)-coated ceria nanoparticles (NPs) were produced. Four differently sized monodispersed samples were produced by using different PVP chain lengths. The chemical and physical properties of these NPs were characterized as prepared and in different ecotoxicology exposure media. Dynamic light scattering analysis showed that the samples were monodispersed, with an unchanged size when suspended in the different media over a 72 h period. Electron microscopy confirmed this and revealed that the larger (ca. 20 nm) particles were aggregates composed of the smaller individual particles (4-5 nm). Electron energy loss spectroscopy (EELS) showed that the smallest and largest samples were composed almost entirely of cerium(III) oxide, with only small amounts of cerium(IV) present in the largest sample. Dissolved cerium concentrations in media were low and constant, showing that the NPs did not dissolve over time. The simple synthesis of the these NPs and their physical and chemical stability in different environmental conditions make them potentially suitable for use as reference materials for (eco)toxicology and surface water environmental studies.

Nanomaterials in the environment: Behavior, fate, bioavailability, and effects—An updated review

“…For instance, Taylor et al () showed that tightly constrained (in size and oxidation state) and well‐characterized ceria NMs gave different algal transcriptomic and metabolomic responses compared with larger scale particles and dissolved phase Ce, although in all cases toxicity was low. Confounding factors to such studies lie in: 1) ensuring that NMs and larger particles are only different with respect to one variable, which is difficult when physical and chemical properties are size dependent, as is the case for ceria and oxidation state; 2) rapid transformations of NMs occuring in complex media such as environmental and exposure media; and 3) precipitation of the dissolved controls after exposure (Merrifield RC et al ). In addition, the limited knowledge of hazard and exposure (Klaine et al ) creates large uncertainties in understanding risk.…”

Development of scalable and versatile nanomaterial libraries for nanosafety studies: polyvinylpyrrolidone (PVP) capped metal oxide nanoparticles

“…[12][13][14][15][16][17][18][19][20][21] Ceria's diversity of uses is due to its properties, 19 the most important of which is its redox potential stemming from its ability to cycle between Ce 3+ and Ce 4+ (which has a characteristic yellow colour). 18,[22][23][24] Nano ZnO is used in solar cells, gas sensors, chemical absorbent varistors, electrical and optical devices, electrostatic dissipative coatings, catalysts for liquid phase hydrogenation, and catalysts for photo-catalytic degradation instead of titanium dioxide (TiO 2 ) NMs. 25 It is also an approved sunscreen ingredient in many countries around the world due to its UV blocking ability.…”

Nanosafety forum for young scientists: a meeting report

“…In the study reported by Heinlaan, bacteria, yeast, protozoa and Daphnia magna were challenged with several nanoparticles, showing the following toxicity order: nAg > nZnO > nCuO > nSiO 2 = MWCNTs = nTiO 2 . nSiO 2 , nTiO 2 and MWCNTs were not toxic in any screening test (EC50 > 100 mg/L) and nano Ag was toxic to all organisms, especially to Daphnia magna.…”

“…Briffa's presentation showed that the protocol for hydrothermal synthesis of PVP capped ceria nanoparticles (2) Be in multi-walled carbon nanotubes [MWCNTs]) is also a possibility, but radiolabel stability needs to be carefully determined. More work needs to be done to establish radiolabeling protocols and characterise the radiolabeled NPs, for different particle types.…”