Carbon nanotubes could be new pathogen weapon
as E. coli, according to a new study.
Researchers at Yale University discovered the potential use of single walled carbon nanotubes as food safety weapon while studying the toxicity of such tiny constructions. This "nanoscience version of a David-and-Goliath story" was hailed in an American Chemical Society preview of the work as the first direct evidence that "carbon nanotubes have powerful antimicrobial activity, a discovery that could help fight the growing problem of antibiotic resistant infections." The manufacture of products using nanotechnology - the science of manipulating matter at the level of atoms and molecules in order to alter properties - has exploded in recent years. Although it has been touted as the next revolution in many industries, including food manufacturing and packaging, public concerns have been raised over the potential health or environmental hazards nanotechnology may pose. "We began the study out of concerns for the possible toxicity of nanotubes in aquatic environments and their presence in the food chain," said Menachem Elimelech, a chemical and environmental engineering scientist at Yale and senior author of the study paper. "While nanotubes have great promise for medical and commercial applications there is little understanding of how they interact with humans and the environment." Nanotubes are microscopic carbon cylinders, thousands of times smaller than a human hair. The researchers undertook to find out more about where and how they are toxic. The researchers found that the nanotubes work by severely damaging E. coli's cell walls, according to the report, published in the American Chemical Society journal Langmuir. Using the simple E. coli as test cells, the researchers incubated cultures of the bacteria in the presence of the nanotubes for up to an hour. The microbes were killed outright - but only when there was direct contact with aggregates of the carbon nanotubes that touched the bacteria. Elimelech speculates that the long, thin nanotubes puncture the cells and cause cellular damage. In a report published in July, the consultancy Helmut Kaiser forecast that the nanotechnology food packaging industry could be worth as much as €22bn ($30bn), based on current market value estimates, while some estimates said the market could be worth €740bn ($1tn) by 2013. Only last month, the UK's University of Nottingham opened a €4.7 million nanotechnology research centre for what it termed "the technology for the future." However, not everyone is as seemingly enthusiastic, and several industry players have lobbied regulatory bodies for more research. At the beginning of August an international coalition of consumer, environmental and labour groups issued what the member groups described as an urgent call for strong nanotechnology oversight, along with a 15-page document setting out proposed principles to guide regulators in their oversight of nanotechnologies and nanomaterials. According to the coalition, which operates under the umbrella group International Center for Technology Assessment, "evidence indicates that current nanomaterials may pose significant health, safety, and environmental hazards". "In addition, the profound social, economic, and ethical challenges posed by nano-scale technologies have yet to be addressed," the group added.
