Funding: National Science Foundation, Environmental Chemical Sciences (ECS)

Collaborators: Mary Bisson and Joseph Gardella (University at Buffalo)

The increasing use of engineered nanomaterials (ENMs) in agriculture, energy production, environmental remediation, diagnostics, and biomedical applications1 has generated concerns regarding the potential impacts of ENMs on the environment and human health. Due to the unlimited applications of ENMs, it is expected that they will end up in the environment at levels that may pose risks to non-target organisms. Plants are among the organisms that will be directly impacted by ENMs entering the environment, therefore an improved understanding of the uptake mechanisms and translocation of ENMs by plants is needed to facilitate the assessment of potential risks associated with environmental contamination by ENMs. In this project, silver nanoparticles (AgNPs) will be used to study the influence of surface chemistry and plant exudates on the fate and phytotoxicity of ENMs when taken up by plants. Our team is investigating the fate and toxicity of ENMs that are becoming widely used in many industrial, agricultural and consumer products. The specific objectives of this research are:

1. To identify important reactions of ENMs with natural organic compounds found in plant root exudates that result in surface modifications and changes in speciation of ENMs, which in turn influence ENM phytotoxicity (toxicity specific to plants) and stability in the environment
2. To elucidate mechanisms of ENM plant uptake by determining localization and chemical speciation of silver in plant cells as a function of the surface chemistry of ENM and the chemistry of the root micro-environment, called the rhizosphere

To achieve these goals, AgNPs will be used as model ENM and Arabidopsis thaliana will serve as the model plant species in the series of experiments that will be performed to elucidate the mechanisms of internalization and transformation of AgNPs in plants. This research identifies important interactions between AgNPs and natural organic compounds in plant root exudates that result in surface modifications and changes in the speciation of ENMs. The composition of root exudates from Arabidopsis thaliana and the changes that occur when plant is treated with AgNPs will be characterized using liquid chromatography with mass spectrometry. The localization and speciation of Ag in the plant cells will be determined by X-ray absorption fine structure spectroscopy and time of flight secondary ion mass spectrometry. Results from this research will generate fundamental knowledge critical in developing new regulations to minimize the negative impacts of ENMs, and in promoting compatibility between environmental safety and nanotechnology.