A huge study published in the research journal Nature Nanotechnology suggests that some forms of Carbon nanotubes could be as harmful as asbestos fibers if inhaled in to the body and to the Esophagus and lungs. The study confirms that specific types of carbon nanotubes have the potential to cause malignant mesothelioma including Pleural mesothelioma that can take 30 to 40 years after initial asbestos exposure to surface to life. The research study suggests that nanotubes that are very thin, long and multi-walled look like asbestos fibers, and behave like asbestos fibers. This image on the left shows Carbon nanotubes in the top half, and tissues of asbstos fibers in the second half. You can see the similarities between the two fibers, and scientists think that carbon nanotubes can also cause mesothelioma lung cancer & other malignant diseases.
Carbon nanotubes are becoming popular in industrial use due to their weight as light as plastic and strength stronger than steel. Discovered by scientists almost 20 years ago, carbon nanotubes are being used in energy-efficient batteries, sophisticated electronics as well as new pharmaceutical drugs. Such widespread is the use of carbon nanotubes such that the U.S. publication Chemical & Engineering News says annual sales could reach up to $2 billion in 2009. Andrew Maynard, Chief Science Advisor to the Project on Emerging Nanotechnologies and co-author of the research study above quotes, "This study is exactly the kind of strategic, highly focused research needed to ensure the safe and responsible development of nanotechnology. It looks at a specific nanoscale material expected to have widespread commercial applications and asks specific questions about a specific health hazard. Even though scientists have been raising concerns about the safety of long, thin carbon nanotubes for over a decade, none of the research needs in the current U.S. federal nanotechnology environment, health and safety risk research strategy address this question."
Lead researcher of the study, Professor Kenneth Donaldson at University of Edinburgh (UK) quotes, "We still don't know whether carbon nanotubes will become airborne and be inhaled, or whether, if they do reach the lungs, they can work their way to the sensitive outer lining. But if they do get there in sufficient quantity, there is a chance that some people will develop cancer--perhaps decades after breathing the stuff." He adds, "Short or curly carbon nanotubes did not behave like asbestos, and by knowing the possible dangers of long, thin carbon nanotubes, we can work to control them. It's a good news story, not a bad one. It shows that carbon nanotubes and their products could be made to be safe." In conclusion, Mr. Donaldson quotes, "More research is still needed if we are to understand how to use these materials as safely as possible."Anthony Seaton, MD and professor at University of Aberdeen in the UK as well as co-author of the study quotes, "The toll of asbestos-related cancer, first noticed in the 1950s and 1960s, is likely to continue for several more decades even though usage reduced rapidly some 25 years ago. While there are reasons to suppose that nanotubes can be used safely, this will depend on appropriate steps being taken to prevent them from being inhaled in the places they are manufactured, used and ultimately disposed of. Such steps should be based on research into exposure and risk prevention, leading to regulation of their use. Following this study, the results of which were foreseen by the Royal Society in the U.K. in 2004, we can no longer delay investing in such research." A further study in the UK was done such that material was injected in to abdominal cavity of mice which could show signs of malignant tumor development in the lung linings, and the results were clear, long thin carbon nanotubes showed the same effects as asbestos fibers would, in the abdominal cavity of mice. Researchers say asbestos fibers are harmful because they are thin and lastic enough to penetrate deep in to the lungs, as well as block the lungs' ability to get rid of particles via the immune system; carbon nanotubes show such similar properties as well.
Further Research
Carbon nanotubes show extraordinary strength and unique electrical properties as well as efficient conductors of heat. A conductor of heat is an electrical substance that transfer thermal energy between neighbouring molecules due to changes in temperature. Carbon nanotubes can be single-walled with a diameter of close to 1 nanometer and are used often in electrical wiring as well as field effect transistors (FET). The other type of carbon nanotube is the multi-walled that consists of multiple rolled layers (concentric tubes) of graphite as opposed to single-walled that contains only one layer of graphite called graphene.
To view more detailed information about Carnon nanotubes, visit Wikipedia's page about Carbon Nanotubes @ http://en.wikipedia.org/wiki/Carbon_nanotube