Nanotubes: no harm to health detected
Carbon nanotubes, hollow cylinders whose thickness is 50,000 times less than the thickness of a human hair, are a promising carrier for targeted drug delivery. However, the lack of information about what happens to them in the body is the main obstacle to the development of this direction.
Earlier studies have shown that most of the nanomaterials entering the body accumulate in the liver and spleen, but how long they stay there remained unclear until recently. Stanford University scientists working under the guidance of Professor Hongjie Dai were able to partially answer this question.
To track the fate of nanotubes in the body of mice, scientists used the method of Raman spectroscopy, in which the light of a laser beam causes the glow of molecules present in the body. The effect of the laser beam leads to significant changes in the energy state of the molecules. Carbon nanotubes, consisting exclusively of carbon atoms, mainly organized into interconnected hexagonal rings, emit a strong glow in response to the action of a laser beam. This allows you to identify their location and concentration in the blood and various organs.
For the first time, the authors conducted a systematic study of the circulation and excretion of nanotubes, the results of which showed that nanotubes are excreted from the body mainly with excrement (entering the digestive tract as part of bile) and partially with urine. In general, a three-month experiment on mice demonstrated that the nanotubes accumulating in the body do not have a toxic effect.
None of the animals died, while none of them had any abnormalities in the composition of blood and major organs. The animals looked absolutely healthy and gained weight in the same way as the animals of the control group.
Article by Zhuang Liu et al. Circulation and long-term fate of functionalized, biocompatible single-walled carbon nanotubes in mice probed by Raman spectroscopy published in PNAS – Early Edition 29.01.2008.
It is possible that the data obtained extend to other types of nanoparticles, but unambiguous conclusions are impossible without further research.
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of Stanford University.
05.02.2008