Genome-wide bacterial toxicity screening uncovers the mechanisms of toxicity of a cationic polystyrene nanomaterial
Date
2012
Authors
Ivask, A.
Suarez, E.
Patel, T.
Boren, D.
Ji, Z.
Holden, P.
Telesca, D.
Damoiseaux, R.
Bradley, K.
Godwin, H.
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Journal article
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Environmental Science and Technology, 2012; 46(4):2398-2405
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Abstract
By exploiting a genome-wide collection of bacterial single-gene deletion mutants, we have studied the toxicological pathways of a 60-nm cationic (amino-functionalized) polystyrene nanomaterial (PS-NH 2) in bacterial cells. The IC 50 of commercially available 60 nm PS-NH 2 was determined to be 158 μg/mL, the IC5 is 108 μg/mL, and the IC90 is 190 μg/mL for the parent E. coli strain of the gene deletion library. Over 4000 single nonessential gene deletion mutants of Escherichia coli were screened for the growth phenotype of each strain in the presence and absence of PSNH 2. This revealed that genes clusters in the lipopolysaccharide biosynthetic pathway, outer membrane transport channels, ubiquinone biosynthetic pathways, flagellar movement, and DNA repair systems are all important to how this organism responds to cationic nanomaterials. These results, coupled with those from confirmatory assays described herein, suggest that the primary mechanisms of toxicity of the 60-nm PS-NH 2 nanomaterial in E. coli are destabilization of the outer membrane and production of reactive oxygen species. The methodology reported herein should prove generally useful for identifying pathways that are involved in how cells respond to a broad range of nanomaterials and for determining the mechanisms of cellular toxicity of different types of nanomaterials
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Copyright 2012 American Chemical Society.