Nanomaterials can exhibit multiple physiochemical properties, including high electric conduction, high tensile strength, heat tolerance, UV blocking and antimicrobial activity. They are proposed for biomedical purposes such as imaging wound treatment, targeting disease-causing and cancer cells, and delivery of therapeutic agents. Consumer use includes sun blocks, make-up, clothing and electronic devices. Industrially, their potential uses appear to be growing exponentially. Environmentally, they have been proposed for enhancing the breakdown of organic contaminants and the immobilization of inorganics. As with any new technology, rapid and abundant use has the potential to lead to introduction into the environment, through consumer use, industrial mishaps or intentional release. However, there are limited numbers of studies that have looked at the impact these particles will have in an environmental setting. Recent work has addressed the potential toxicity of nanoparticles to humans, animals and clinically important bacteria. The collective results of these studies are mixed with some researchers reporting limited toxicity, while others show significant cellular impacts with exposure to even the smallest particles. There has been almost no work performed to date investigating the impact of nanoparticle exposure on plants. As plants are a primary producer in the food chain, negative impacts on plant growth could lead to significant trophic impacts as well as plant transfer of the particles.
In this study, they will look at how plants and nanoparticles interact. They will decipher the impact of particle size and shape on uptake and translocation within the plant tissue, specifically focusing on gold, silver and palladium particles, which between them currently used in multiple applications. They will we be using the tomato plant, Lycopersicon esculentum L. for these studies. They will examine plant-nanoparticle interactions using multiple methods including: brightfield and fluorescent microscopy to determine uptake and distribution, scanning and transmission electron microscopy to look at uptake and potential damage to cellular membranes, and synchrotron x-ray microspectroscopy to look at movement of gold particles throughout the plant. These parameters will be measured on plants exposed to nanoparticles both in bare solution and soils. This will allow them to determine the impact of soils on bioavailability of the particles to plant roots and subsequent uptake. They will also examine the plants on a genetic level to determine changes in gene expression, using both microarray analysis and quantitative real time-PCR and quantify those changes. Finally, they will perform preliminary feeding studies to determine how ingested nanoparticles that are part of a plant matrix will be retained in the insects that feed on the plants. This project will be done in collaboration with scientists in the field who have extensive experience in looking at toxicity, detection and quantification of nanoparticles in various eukaryotic systems.
A better understanding of the potential impacts can have broader impacts through supplying data for the introduction of important regulations regarding use, disposal and introduction of nanomaterials in the environment. What they learn here will be synthesized and transmitted to the next generation of students and researchers so they can fully appreciate not only the potential, but also the concerns about the uses of nanotechnology.
