Oxidative stress (OS) is an important mechanism of engineered nanomaterials (ENM) toxicity. Several acellular assays are used to measure OS elicited by ENM; yet little comparative method evaluation exists. We compared the dichlorofluorescin (DCFH) assay, which measures Reactive Oxygen Species, with the Ferric Reducing Ability of Serum (FRAS) assay, which measures biological oxidant damage. Several classes of diverse, properly characterized ENM, including 14 CNTs, were evaluated. Intracellular oxidative stress (oxidized/reduced glutathione) was assessed for a representative subset of these ENM. In acellular assays, only 10/28 ENM were DCFH-positive vs. 21/28 in FRAS. For CNTs, 9/14 were DCFH positive vs. 14/14 in FRAS. FRAS exhibited stronger and more robust associations with specific surface area and several transition metals and was more sensitive than DCFH in predicting intracellular oxidative stress. Based on these observations, FRAS appears better suited than DCFH for oxidative stress screening of ENM. Validation against higher toxicity endpoints in cells and inflammation in animals is in progress.

Screening for oxidative damage by engineered nanomaterials: A comparative evaluation of FRAS and DCFH

244th National Meeting (2012)

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