Uptake, distribution and toxicity of gold nanoparticles in tobacco (Nicotiana xanthi) seedlings

Abstract

Understanding plant interactions with nanoparticles is of increasing importance for assessing their toxicity and trophic transport. The primary objective of this study was to assess uptake, biodistribution and toxicity associated with exposure of tobacco plants (Nicotiana xanthi) to gold nanoparticles (AuNPs). We employed synchrotron-based X-ray microanalysis with X-ray absorption near-edge microspectroscopy and high resolution electron microscopy to localize AuNPs within plants. Results from these experiments reveal that AuNPs entered plants through the roots and moved into the vasculature. Aggregate bodies were also detected within root cell cytoplasm. Furthermore, AuNP uptake was size selective as 3.5 nm AuNP spheres were detected in plants but 18 nm AuNPs remained agglomerated on the root outer surfaces. Finally, leaf necrosis was observed after 14 days of exposure to 3.5 nm AuNPs. Overall, results of this work show the potential for AuNPs to enter plants through size-dependent mechanisms, translocate to cells and tissues and cause biotoxicity.

Keywords::

• Gold nanoparticles
• Nicotiana xanthi
• XANES
• spectroscopy

Acknowledgements

We would like to thank Antonio Lanzirotti for invaluable assistance in the synchrotron analysis of the plant tissue.

Declaration of interest: This work was supported by funds from the University of South Carolina NanoCenter and NSF award CBET-0828441. The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.