EPA Science Inventory

Production and Consumption of Reactive Oxygen Species by Fullerenes

Citation:

Kong, Lynn AND R. G. ZEPP. Production and Consumption of Reactive Oxygen Species by Fullerenes. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 31(1):136-143, (2012).

Description:

Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen peroxide, and hydroxyl radicals) by Buckminster fullerene (C(60) ) and fullerenol were investigated in aqueous systems. Fullerenol exhibits higher photoproduction efficiency of singlet oxygen and superoxide than aqueous suspensions of C(60) aggregates (aqu/nC(60) ), and this higher efficiency results in higher steady-state concentrations of these two ROS. Transmission electron microscopy indicates that the C(60) molecules in aqu/nC(60) are much more closely packed than the C(60) cages in fullerenol. These observations provide additional evidence that the lower ROS production efficiency of aqu/nC(60) is attributable primarily to efficient self-quenching of C(60) triplet states. Production of singlet oxygen by aqu/nC(60) is accelerated by increasing oxygen concentration and in part is sensitized by fluorescent photoproducts that accumulate during irradiation. The fullerenes react slowly with singlet oxygen (second-order rate constant <4 × 10(5)  M(-1)  s(-1) ), but react rapidly with hydroxyl radicals (second-order rate constants of 5.4 × 10(9) and 4 × 10(8)  M(-1)  s(-1) for aqu/nC(60) and fullerenol, respectively). These results show that environmental conditions, including light exposure and oxygen concentration, have the potential to impact the generation of toxic ROS by fullerenes.

Purpose/Objective:

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URLs/Downloads:

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Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 01/31/2012
Completion Date: 01/31/2012
Record Last Revised: 01/07/2013
Record Created: 02/16/2011
Record Released: 02/16/2011
OMB Category: Other
Record ID: 233324

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL EXPOSURE RESEARCH LAB

ECOSYSTEMS RESEARCH DIVISION

IMMEDIATE OFFICE