BER launches Environmental System Science Program. Visit our new website under construction!

U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Fundamental Understanding of Engineered Nanoparticle Stability in Aquatic Environments
Published: January 25, 2018
Posted: March 22, 2019

The Science
It is commonly true that a diluted colloidal suspension is more stable over time than a concentrated one, because dilution reduces collision rates, so delays formation of aggregates. However, the research team observed the opposite relationship between stability and concentration for some engineered ligand-coated nanoparticles

The Impact
Because the stability of nanoparticles determines their physicochemical and kinetic behavior including toxicity, dilution induced instability needs to be understood to realistically predict the behavior of engineered ligand-coated nanoparticles in aqueous systems.

Summary
It is commonly true that a diluted colloidal suspension is more stable over time than a concentrated one, because dilution reduces collision rates of the particles and therefore delays formation of aggregates. However, this generalization does not apply for some engineered ligand-coated nanoparticles (NPs). The researchers observed the opposite relationship between stability and concentration of NPs. They tested four different types of NPs; CdSe-11-mercaptoundecanoic acid, CdTe-polyelectrolytes, Ag-citrate, and Ag-polyvinylpirrolidone. The results showed that dilution alone induced aggregation and subsequent sedimentation of the NPs that were originally monodispersed at very high concentrations. Increased dilution caused NPs to progressively become unstable in the suspensions. The extent of the dilution impact on the stability of NPs is different for different types of NPs. The team hypothesizes that the unavoidable decrease in free ligand concentration in the aqueous phase following dilution causes detachment of ligands from the suspended NP cores. The ligands attached to NP core surfaces must generally approach exchange equilibrium with free ligands in the aqueous phase; therefore, ligand detachment and destabilization are expected consequences of dilution. More studies are necessary to test this hypothesis. Because the stability of NPs determines their physicochemical and kinetic behavior including toxicity, dilution-induced instability needs to be understood to realistically predict the behavior of engineered ligand-coated nanoparticles in aqueous systems.

Contacts
BER Program Manager
David Lesmes, SC-23.1
david.lesmes@science.doe.gov

Principal Investigator
Jiamin Wan, LBNL
jwan@lbl.gov

Funding
Support for the project is through the Subsurface Biogeochemical Research program of the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science, under contract DE-AC02- 05CH11231.

Publications
Wan, J., Y. Kim, M.J. Mulvihill, and T. K. Tokunaga. "Dilution destabilizes engineered ligand-coated nanoparticles in aqueous suspensions." Environmental Toxicology and Chemistry 37(5), 1301–1308 (2018). [DOI:10.1002/etc.4103].

Topic Areas:

  • Research Area: Subsurface Biogeochemical Research

Division: SC-33.1 Earth and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco
Objectives

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)