Environmental feedbacks and engineered nanoparticles: mitigation of silver nanoparticle toxicity to Chlamydomonas reinhardtii by algal-produced organic compounds

Louise M Stevenson; Helen Dickson; Tin Klanjscek; Arturo A Keller; Edward McCauley; Roger M Nisbet

doi:10.1371/journal.pone.0074456

Environmental feedbacks and engineered nanoparticles: mitigation of silver nanoparticle toxicity to Chlamydomonas reinhardtii by algal-produced organic compounds

PLoS One. 2013 Sep 23;8(9):e74456. doi: 10.1371/journal.pone.0074456. eCollection 2013.

Authors

Louise M Stevenson¹, Helen Dickson, Tin Klanjscek, Arturo A Keller, Edward McCauley, Roger M Nisbet

Affiliation

¹ Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America.

Abstract

The vast majority of nanotoxicity studies measures the effect of exposure to a toxicant on an organism and ignores the potentially important effects of the organism on the toxicant. We investigated the effect of citrate-coated silver nanoparticles (AgNPs) on populations of the freshwater alga Chlamydomonas reinhardtii at different phases of batch culture growth and show that the AgNPs are most toxic to cultures in the early phases of growth. We offer strong evidence that reduced toxicity occurs because extracellular dissolved organic carbon (DOC) compounds produced by the algal cells themselves mitigate the toxicity of AgNPs. We analyzed this feedback with a dynamic model incorporating algal growth, nanoparticle dissolution, bioaccumulation of silver, DOC production and DOC-mediated inactivation of nanoparticles and ionic silver. Our findings demonstrate how the feedback between aquatic organisms and their environment may impact the toxicity and ecological effects of engineered nanoparticles.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Batch Cell Culture Techniques
Carbon / pharmacology
Chlamydomonas reinhardtii / drug effects*
Chlamydomonas reinhardtii / growth & development
Chlamydomonas reinhardtii / metabolism*
Citrates / pharmacology
Environmental Monitoring*
Feedback*
Ions
Metal Nanoparticles / toxicity*
Models, Biological
Nanotechnology*
Organic Chemicals / metabolism*
Organic Chemicals / pharmacology*

Substances

Citrates
Ions
Organic Chemicals
Carbon

Grants and funding

This research was supported by the US National Science Foundation (http://www.nsf.gov/) and the US Environmental Protection Agency (http://www.epa.gov/) under Cooperative Agreement Number EF-0830117, the National Science Foundation Graduate Research Fellowship (http://www.nsfgrfp.org/) under Grant No. DGE- 1144085, and the Croatian Ministry for Science, Education and Sport (http://public.mzos.hr/) Grant 098-0982934-2719. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.