Guidance to improve the scientific value of zeta-potential measurements in nanoEHS

Lowry, Gregory V.; Hill, Reghan J.; Harper, Stacey L.; Rawle, Alan F.; Hendren, Christine Ogilvie; Klaessig, Fred; Nobbmann, Ulf; Sayre, Philip; Rumble, John

doi:10.1039/c6en00136j

Cited by 301 publications

(276 citation statements)

References 32 publications

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“…Zinc oxide NP agglomeration increased significantly at 72 h in the MQW, reaching a final HDD of 734 ± 72 nm after 120 h. Significantly larger agglomerates were observed in the NCM with the HDD increased to 1008 ± 128 nm after 120 h. The ZP for the NPs in NCM did not differ significantly over the 5‐d experimental period (–15.7 to –16.9 mV), suggesting that the majority of particle agglomeration occurred almost instantaneously (Supplemental Data, Figure S1). The ZP was not determined in the MQW because of the lack of conductivity for determining electrophoretic mobility (Lowry et al ).…”

Section: Resultsmentioning

confidence: 99%

“…Typically, ZP would be used to measure suspension stability; however, the low conductivity of pure water precludes accurate measurement (Lowry et al ). The ZP in the NCM was slightly negative and remained fairly constant (–15.7 to –16.9 mV) over 5 d in solution, further supporting the lack of suspension stability leading to agglomeration.…”

Section: Discussionmentioning

confidence: 99%

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Comparative dissolution, uptake, and toxicity of zinc oxide particles in individual aquatic species and mixed populations

Harper

2019

Enviro Toxic and Chemistry

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Potential differences in species susceptibility to nanoparticle (NP) contaminants make the use of multispecies community toxicity testing strategies beneficial in understanding NP risk to aquatic environments. Because of the limited knowledge of zinc oxide (ZnO) NP fate and toxicity, we conducted multispecies exposures and compared the responses of individual species to the same species in a community comprised of algae ( Chlamydomonas reinhardtii ), bacteria ( Escherichia coli ), crustaceans ( Daphnia magna ), and zebrafish ( Danio rerio ). Different‐sized ZnO particles and ionic Zn were compared to investigate the contribution of particulate and dissolved Zn to aquatic organism toxicity. Each organism and community was exposed to Zn sources at 0.08, 0.8, and 8 mg Zn/L. The present results indicate that all 3 types of Zn elicited differential toxicity among test organisms, with stronger adverse outcomes observed in single species than within a community. The community assay (nanocosm) we developed increased resilience to all Zn exposures by 5 to 10% compared to individual exposures at equivalent concentrations. In addition, the uptake and toxicity of ZnO particles to aquatic communities appear to be driven by rapid dissolution and the concomitant impacts of zinc ion toxicity, and the size of the ZnO particles had little impact on uptake or toxicity. The nanocosm assay could be a useful screening tool for rapidly assessing the potential impacts of nanomaterials to aquatic species. Environ Toxicol Chem 2019;38:591–602. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Comparative dissolution, uptake, and toxicity of zinc oxide particles in individual aquatic species and mixed populations

Harper

2019

Enviro Toxic and Chemistry

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“…The result obtained for TZM are in contrast with the high negative charge density of the g-eHER2 surface, as judged by the results shown in Table 2, presumably due to exposed aspartic and glutamic acids residues. Changes in either the sign or the magnitude of the ζpotential of these systems can serve as a qualitative indication of changes in the surface charge density, e.g., specific interactions between the biomacromolecules (55).…”

Section: Discussionmentioning

confidence: 99%

Hydrodynamic and electrophoretic properties of Trastuzumab/HER2 complexes. Experiments and modeling.

Ramos

Cruz

et al. 2018

Preprint

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The combination of hydrodynamic and electrophoretic experiments and computer simulations is indeed a powerful approach to study the interaction between proteins. In this work, we present hydrodynamic and electrophoretic experiments in aqueous solution along with molecular dynamics and hydrodynamic modeling to monitor and compute biophysical properties of the interactions between the extracellular domain of the HER2 protein (eHER2) and the monoclonal antibody trastuzumab (TZM). The importance of this system relies on the fact that the overexpression of HER2 protein is related with the poor prognosis breast cancers (HER2++ positives) being the TZM a monoclonal antibody for the treatment of this cancer. We have found and characterize two different complexes between the TZM and eHER2 proteins (1:1 and 1:2 TZM:eHER2 complexes). The conformational features of these complexes regulate their hydrodynamic and electrostatic properties. Thus, the results indicate a high degree of molecular flexibility in the systems, that ultimately leads to higher values of the intrinsic viscosity and as well as lower values of diffusion coefficient than those expected for simple globular proteins. A highly asymmetric charge distribution is detected for the monovalent complex (1:1 complex), which has strong implications in correlations between the experimental electrophoretic mobility and the modeled net charge. In order to understand the dynamics of these systems and the role of the specific domains involved, it is essential to find biophysical correlations between dynamics, macroscopic transport and electrostatic properties. The results should be of general interest for researchers working in this area.

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“…Two examples include the development of the ISA-TAB-nano data sharing file format extension by the open National Cancer Institute Nanotechnology Working Group (NCI NanoWG) 9 and the community-developed guidance on the proper execution and interpretation of zeta potential measurements. 10 Similar to those examples, here we have developed proposed media for environmental and biological nanosafety assessment research and their parameters from within a group of researchers across academic, 6 commercial and governmental sectors who are already immersed in investigating, modeling, and making decisions based on forecasts of nanomaterial behavior and effects.…”

Section: Introductionmentioning

confidence: 99%

Harmonizing across environmental nanomaterial testing media for increased comparability of nanomaterial datasets

Geitner

Hendren

Cornelis

et al. 2020

Environ. Sci.: Nano

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Guidance to improve the scientific value of zeta-potential measurements in nanoEHS

Abstract: Nanoparticle zeta potentials are easy to measure and proposed as a required property for complete nanoparticle characterization, but relevant metadata must be reported with zeta potential to be scientifically useful.

Cited by 301 publications

References 32 publications

Comparative dissolution, uptake, and toxicity of zinc oxide particles in individual aquatic species and mixed populations

Comparative dissolution, uptake, and toxicity of zinc oxide particles in individual aquatic species and mixed populations

Hydrodynamic and electrophoretic properties of Trastuzumab/HER2 complexes. Experiments and modeling.

Harmonizing across environmental nanomaterial testing media for increased comparability of nanomaterial datasets

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