At the core of a multitude of futuristic technologies, carbon nanotubes have drawn just as much fire as praise in regards to their potential future role in cutting-edge medical technologies. A recent study conducted by a team of Swedish and American scientists may help quiet critics, however, by showing that carbon nanotubes may be able to break down naturally in the body.Despite their potential, carbon nanotubes have been the subject of a barrage of unanswered questions regarding their toxicity and behavior in the body. Reports have suggested that the materials could cause tissue damage; some have even gone so far as to liken them to asbestos. This study, led by researchers at the Karolinska Institutet (Stockholm), the University of Pittsburgh (PA), and the National Institute for Occupational Safety and Health (Atlanta), on the other hand, proposes that carbon nanotubes can be broken by myeloperoxidase (MPO), an enzyme found in neutrophils, a type of white blood cell."Previous studies have shown that carbon nanotubes could be used for introducing drugs or other substances into human cells," says Bengt Fadeel, an associate professor at the Karolinska Institutet. "The problem has been not knowing how to control the breakdown of the nanotubes, which can cause unwanted toxicity and tissue damage. Our study now shows how they can be broken down biologically into harmless components." The enzyme can break down carbon nanotubes into water and carbon dioxide, which are compatible with the human body.Pending further investigation and evidence, this revelation could facilitate development of next-generation medical technologies.