Nanotechnology may promise miracles for humans, but it seems that it spells death for plants. There have been fascinating reports on how researchers are using particles that are 1/100,000 the width of a human hair to deliver drugs to specific cells in the body.
Touted future cancer cures and fire resistant material aside there have been a number of uses for carbon nanotubes. These are the cylindrical carbon molecules that are used in biomedical engineering and medical chemistry. They can carry proteins, nucleic acids and drugs along with them and deliver them to specific cells and organs.
However the effect of nanoparticles on plants has not been studied in much detail so far. A fact that Dr Nan Yao and his team in China hope to remedy. They have been treating the cells of rice and Arabidopsis with carbon nanotubes and assessed the impact.
They have studied the cells for viability, damage to DNA, and the presence of reactive oxygen species. They have found that nanotubes are not exactly 100% healthy for plants due to the nanotoxicity can kill off the plant.
Dr. Yao and his team of researchers isolated cells from rice as well as from the model plant species Arabidopsis. The researchers treated these cells with carbon nanotubes, and then assessed the cells for viability, damage to DNA, and the presence of reactive oxygen species.
The researchers found an increase in levels of the reactive oxygen species hydrogen peroxide. Reactive oxygen species cause oxidative stress to cells, and this stress can result in programmed cell death. Dr. Yao and his colleagues discovered that the effect of carbon nanotubes on cells was dosage dependent—the greater the dose, the greater the likelihood of cell death. In contrast, cells exposed to carbon particles that were not nanotubes did not suffer any ill effects, demonstrating that the size of the nanotubes is a factor in their toxicity.
"Nanotechnology has a large scope of potential applications in the agriculture industry, however, the impact of nanoparticles have rarely been studied in plants," Dr. Yao said. "We found that nanomaterials could induce programmed cell death in plant cells."
Despite the scientists' observations that carbon nanotubes had toxic effects on plant cells, the use of nanotechnology in the agriculture industry still has great promise. The scientists only observed programmed cell death as a temporary response following the injection of the nanotubes and did not observe further changes a day and a half after the nanotube treatments. Also, the researchers did not observe death at the tissue level, which indicates that injecting cells with carbon nanotubes caused only limited injury.
"The current study has provided evidence that certain carbon nanoparticles are not 100% safe and have side effects on plants, suggesting that potential risks of nanotoxicity on plants need to be assessed," Dr. Yao stated. In the future, Dr. Yao and colleagues are interested in investigating whether other types of nanoparticles may also have toxic effects on plant cells. "We would like to create a predictive toxicology model to track nanoparticles."
Only once scientists have critically examined the risks of nanoparticles can they take advantage of the tremendous potential benefits of this new technology.