More than the ions: The effects of silver nanoparticles on lolium multiflorum

Liyan Yin, Yingwen Cheng, Benjamin Espinasse, Benjamin P. Colman, Melanie Auffan, Mark Wiesner, Jerome Rose, Jie Liu, Emily S. Bernhardt

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Silver nanoparticles (AgNPs) are increasingly used as antimicrobial additives in consumer products and may have adverse impacts on organisms when they inadvertently enter ecosystems. This study investigated the uptake and toxicity of AgNPs to the common grass, Lolium multiflorum. We found that root and shoot Ag content increased with increasing AgNP exposures. AgNPs inhibited seedling growth. While exposed to 40 mg L -1 GA-coated AgNPs, seedlings failed to develop root hairs, had highly vacuolated and collapsed cortical cells and broken epidermis and rootcap. In contrast, seedlings exposed to identical concentrations of AgNO3 or supernatants of ultracentrifuged AgNP solutions showed no such abnormalities. AgNP toxicity was influenced by total NP surface area with smaller AgNPs (6 nm) more strongly affecting growth than did similar concentrations of larger (25 nm) NPs for a given mass. Cysteine (which binds Ag +) mitigated the effects of AgNO 3 but did not reduce the toxicity of AgNP treatments. X-ray spectro-microscopy documented silver speciation within exposed roots and suggested that silver is oxidized within plant tissues. Collectively, this study suggests that growth inhibition and cell damage can be directly attributed either to the nanoparticles themselves or to the ability of AgNPs to deliver dissolved Ag to critical biotic receptors.

    Original languageEnglish
    Pages (from-to)2360-2367
    Number of pages8
    JournalEnvironmental Science and Technology
    Volume45
    Issue number6
    DOIs
    StatePublished - Mar 15 2011

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