Grantee Research Project Results

Carbon Nanomaterials as Environmental Sorbents: Friend or Foe?

EPA Grant Number: F13C20567
Title: Carbon Nanomaterials as Environmental Sorbents: Friend or Foe?
Investigators: Creighton, Megan
Institution: Brown University
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 2014 through August 1, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Fellowship - Chemical Engineering , Academic Fellowships

Objective:

This study is based on the hypothesis that the high aspect ratio and large surface area of GFNs will pose a unique inhalation exposure risk that is not yet properly understood, which may include impairment of the lung's immune defense mechanisms. This research must be carefully validated, as the high surface area and adsorptive properties inherent in graphene- based and other carbon nanomaterials will lead to in vitro assay results that are difficult to interpret correctly.

Approach:

This project will focus on a suite of carbon nanomaterials whose physical properties (such as overall geometry, lateral dimension and/or aspect ratio and surface chemistry) span those of the most common commercially available products. Carbon materials are well-known sorbents for organic compounds in aqueous phases, and the increased surface area associated with nano-scale dimension compounds this inherently strong adsorptive capability. This can significantly alter the profile of their surrounding milieu by, for example, removing essential micronutrients or molecular probes used in in vitro assays. These same interactions also can mediate initial contact with macromolecules, including hydrophobic residues in proteins. Such interactions can lead to protein unfolding, which jeopardizes the structure and therefore the performance of a given protein molecule. The adsorptive interface is only one example of GFN behavior in biological systems; these carbon nanomaterials also can form physical barriers and exhibit antioxidant properties. This study also will investigate the effects of particle size and geometry, which will have implications in cellular interactions (such as recognition and uptake) as well as the transport, deposition and exposure pathways relevant for a given material.

Expected Results:

This research will improve the body of knowledge used in determining the safety of GFNs. Understanding the primary influences guiding the interactions of these materials with their surroundings will lead to the enhancement of research methods and advance the quality of environmental inquiry regarding GFNs. This will eventually lead to more accurate information for environmental decisionmaking, allowing the safe and sustainable development and incorporation of GFN technology into society.

Potential to Further Environmental/Human Health Protection

This research will help correlate GFN characteristics with certain behaviors in biological systems, which will differ from those of the traditional toxicants from which common risk assessment methods developed.
This work will advance the quality of environmental inquiry regarding GFNs by providing guidance on how to avoid misinterpretation of common procedures used to assay these materials, identify the predominant methods of interactions with a variety of species present in a biological environment (including proteins and reactive oxygen species), and allow design criteria that minimize risk.

Supplemental Keywords:

graphene, nanomaterials, risk assessment;

Progress and Final Reports:

2015

Final