Articles by Laura-Jayne Ellis in JoVE
Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization Inder Kaur1, Laura-Jayne Ellis1, Isabella Romer1, Ratna Tantra2, Marie Carriere3,4, Soline Allard5, Martine Mayne-L'Hermite5, Caterina Minelli6, Wolfgang Unger7, Annegret Potthoff8, Steffi Rades7, Eugenia Valsami-Jones1 1School of Geography, Earth and Environmental Sciences, University of Birmingham, 2Analytical Science, National Physical Laboratory, 3INAC-LCIB, Université Grenoble Alpes, 4CEA, INAC-SyMMES, 5NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 6Chemical, Medical and Environmental Science, National Physical Laboratory, 7BAM Division 6.1 'Surface Analysis and Interfacial Chemistry', BAM Federal Institute for Materials Research and Testing, 8Fraunhofer Institute for Ceramic Technologies and Systems Here, we present a step-wise protocol for the dispersion of nanomaterials in aqueous media with real-time characterization to identify the optimal sonication conditions, intensity, and duration for improved stability and uniformity of nanoparticle dispersions without impacting the sample integrity.
Other articles by Laura-Jayne Ellis on PubMed
Impact of Surface Coating and Environmental Conditions on the Fate and Transport of Silver Nanoparticles in the Aquatic Environment The Science of the Total Environment. | Pubmed ID: 27289392 The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water - MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV-visible spectrometry (UV-vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96h (4days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment.
Seasonal Variability of Natural Water Chemistry Affects the Fate and Behaviour of Silver Nanoparticles Chemosphere. | Pubmed ID: 29073569 Understanding the environmental behaviour of nanoparticles (NPs) after release into aquatic systems is essential to predict the environmental implications of nanotechnology. Silver nanoparticles (AgNPs) represent a major class of engineered NPs with a significant potential for environmental impact. Therefore, investigating their transformations in natural waters will help predict their long term environmental fate and behaviour. AgNPs were characterized in natural lake water collected seasonally from the same freshwater source, using column microcosms to assess their behaviour and transport at different depths. Building on our previous work using similar systems with synthetic waters, the influence of water chemistry and NP surface modifications on colloidal stability and dissolution in natural lake water over time was investigated. A simple sedimentation-diffusion model parameterized by the particle properties and total Ag concentration was successfully used to understand AgNPs transport behaviour. PVP coated AgNPs remained colloidally stable, with their transport in the water column dominated by diffusion, and exhibited no significant or substantial changes in data or model parameters for different seasons. Citrate coated AgNPs were susceptible to rapid aggregation, sedimentation, dissolution and reprecipitation; their transport in the water column was determined by both diffusion and sedimentation.