The study sought to establish a connection between exposure to carbon nanotubes and early stage cancer development.
Carbon nanotubes, which are around 10,000 times smaller than the diameter of a human hair but can extend to a height of several centimeters long, have a long, hollow structure.
Researchers wanted to find out whether carbon nanotubes, which are very similar in size and shape to asbestos fibers that are known as a major cancer-causing materials, can also have detrimental effects on our lungs. (Related: Carbon Nanotubes May Pose Asbestos-Like Threat to Human Health.)
According to the research that the scientists conducted on mouse models, certain types of carbon nanotubes caused long-term inflammation in the lungs, like asbestos fibers. After some time, this inflammation resulted in the formation of tumors that are similar to the cancer tumors that are caused by asbestos exposure.
The researchers, however, were not able to determine if there is still cancer risk from exposure to finished products that are made of carbon nanotubes, such as boat hulls, bicycle frames, sports cars, and tennis rackets.
The experts believe that this study may be essential in helping doctors make early diagnoses of cancer that is derived from carbon nanotube exposure, and aid them in identifying more effective methods of therapy for the ailing patient.
“We have demonstrated the potential risks posed by long carbon nanotubes. These findings open up the possibility of more effective and efficient screening of advanced fibers to better identify risks and ensure safety,” said Dr. Craig Poland from the University of Edinburgh's Centre for Inflammation Research.
The study, which has been published in the journal Current Biology, was founded by the Medical Research Council Toxicology Unit.
The insertion of purified carbon nanotubes into budding wheatgrass seems to have a beneficial effect on the plant's early growth. However, in the presence of contaminants, carbon nanotubes seem to harm growing wheatgrass.
According to Rice University chemist Andrew Barron, his team grew wheatgrass in a hydroponic garden – a garden in which you can grow plants without soil using mineral nutrient solutions in water – to assess the potential toxicity of the nanoparticles on the plants.
The results astounded the scientists.
The researchers planted wheatgrass seeds in cotton wool and gave them dispersions that had single-walled or multi-walled nanotubes and purified single-walled nanotubes or iron oxide nanoparticles that imitated leftover catalyst often attached to nanotubes. The solutions used were either water or tetahydrofuran (THF), an industrial solvent, while some of the seeds were given pure water or THF as a control.
Eight days after the wheatgrass had been planted, the purified single-walled nanotubes enhanced the germination rate and shoot growth of these plants, which sprouted an average of 13 percent larger than plants in plain water.
Meanwhile, purified single-walled nanotubes in THF slowed down plant development by 45 percent compared to single-walled nanotubes in water, showing the potential of the nanotubes to serve as carrier for toxic substance.
The researchers think that the findings are such due to nanotubes' hydrophobic (excluding water molecules). They also conducted the study knowing that the industrial manufacture of nanotubes could result in their wide use in different industries, becoming included in the production of cosmetics, military weapons, drugs, fabrics, and water filters.
Finally, they suggested that it might be worth looking at whether hydrophobic substrates that imitate the positive effects that were seen in single-walled nanotubes could be utilized of high-efficiency channeling of water to seeds.
"Our work confirms the importance of thinking of nanomaterials as part of a system rather in isolation. It is the combination with other compounds that is important to understand," Barron said.