Interactions of Natural Organic Matter with C60 Fullerene and their Impact on C60 Transport, Bioavailability and ToxicityEPA Grant Number: R834093
Title: Interactions of Natural Organic Matter with C60 Fullerene and their Impact on C60 Transport, Bioavailability and Toxicity
Investigators: Li, Qilin , Alvarez, Pedro J.
Institution: Rice University
EPA Project Officer: Shapiro, Paul
Project Period: January 1, 2009 through December 31, 2011
Project Amount: $399,995
RFA: Exploratory Research: Nanotechnology Research Grants Investigating Fate, Transport, Transformation, and Exposure of Engineered Nanomaterials: A Joint Research Solicitation - EPA, NSF, & DOE (2007) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
The overall objective of the proposed research is to determine the role of NOM in transport, bioavailability and toxicity of C60 fullerene in surface and ground waters. We aim to test three main hypotheses developed based on our recent preliminary studies: 1) NOM alters the physical-chemical state of nC60 nanoparticles by interfering with C60-C60 molecular interactions; 2) NOM reduces adsorption/deposition of nC60 on subsurface soil and suspended particles in surface water by altering their physicochemical properties and interfering with nC60- surface interactions; 3) nC60 does not penetrate into the cell cytoplasm nor permeabilizes the cell by puncturing the membrane, but it interferes with the redox activity of bacteria. NOM attenuates nC60 toxicity by decreasing the bioavailability of nC60 and hindering its ability to oxidize bacterial membranes and perturb bacterial respiration.
The project investigates the effect of NOM-nC60 interactions on three key aspects of nC60 environmental behavior: 1) C60 “solubility”, physicochemical properties of nC60 nano-particles, and the chemical nature of NOM-C60 interactions will be characterized using advanced analytical techniques in a wide range of solution conditions representing natural water, including different type and concentration of NOM; 2) Mechanisms and kinetics of partition/deposition and transport of nC60 will be determined in the presence and absence of NOM at both micro-, and macro- scales using quartz crystal microbalance with dissipation monitoring and packed column experiments, respectively; 3) Molecular level mechanisms of nC60 toxicity to bacteria will be probed using novel experimental methods and the impact of NOM will be assessed by comparing cell association and antimicrobial activity in the presence and absence of NOM. Structure-function analysis will be performed to relate nC60 physicochemical properties to its transport behavior and toxicity with and without NOM.
The outcome of the project is expected to provide 1) a realistic estimate of C60 exposure levels in natural aqueous environment; 2) quantitative description of nC60 transport behavior in systems well representing the natural aqueous environment; 3) identification of major chemical interactions that nC60 may encounter in the aqueous environment; and 4) a realistic toxicity level and toxicity mechanisms of nC60 in natural environment. The information obtained is critical to predicting the potential level of contamination of the natural aqueous environment by mass production of C60 fullerene and the consequent impact on the microbial community. The structure-function relationship will help establishing safety guidelines for industrial and environmental exposures and disposal.