One low-dose exposure of gold nanoparticles induces long-term changes in human cells.
We report the in vitro long-term (20 wk) changes in cells exposed to well-characterized gold nanoparticles (Au NPs) with varying shapes and surface coatings under both chronic (exposure to Au NPs continuously over 20 wk) and nonchronic (initial acute cell exposure to Au NPs, followed by 20 wk in NP-free cell media) conditions. Both chronic and nonchronic Au NPs exposures at low dose induce modifications at the gene level after long periods. In attempt to overcome from the injuries caused by nanoparticle exposure, genes related to oxidative stress, cell cycle regulation, and inflammation are among those presenting differential expression levels. Surprisingly, the nonchronic exposure induced more gene expression changes than its chronic counterpart and the stress effects caused by this type of exposure were sustained even after 20 wk without any additional NP exposure. NP surface chemistry played an important role in the alteration of gene regulation. Overall, our data suggest that (i) cells can adaptively respond to chronic, low-level NP insults; (ii) the cell stress response is not reversible over time upon removal of NPs upon acute, nonchronic exposure; and (iii) polyethylene glycol is not as benign a surface chemistry as is generally supposed.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Priscila
P
Falagan-Lotsch
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Elissa M
EM
Grzincic
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801 murphycj@illinois.edu.
Catherine J
CJ
Murphy
D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D053263:Gene Regulatory Networks / Q000187:drug effects*; D006046:Gold / Q000737:chemistry / Q000494:pharmacology / Q000633:toxicity*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects; D011092:Polyethylene Glycols / Q000633:toxicity; D023382:Toxicity Tests, Acute; D036401:Toxicity Tests, Chronic
D011092:Polyethylene Glycols; D006046:Gold
acute exposure; chronic exposure; gene expression; gold nanoparticles; surface chemistry