Diamonds love the extremes: For the formation of the carbon lattice giving diamond their unique properties, very high temperature and pressure is necessary. On the Earth, these conditions can be found only deep within the earth, therefore finding appropriate locations is very hard. However in space one can often find these suitable requirements. Recently scientists at the University of Stuttgart have investigated diamonds that were formed under interstellar conditions. And the researchers were surprised to find nanodiamonds that are comprised of only about 500 carbon atoms. It makes the precious diamonds more interesting particulary for various biological researches. The journal Nature Nanotechnology reported about this in its new edition.
In cooperation with a Russian science team, Dr. Sang- Yun Lee and Torsten Rendler of the 3rd Physics Institute at the University of Stuttgart (supervised by Prof. Jörg Wrachtrup ) studied remains of meteorites that have been found in Siberia. "It was known that meteorites contain diamonds. However, we were surprised by their size and physical properties. ", the Stuttgart physicists explained. While to the most people large gems are of interest, scientists are looking for very small diamonds. Studies have shown that nanodiamonds significantly increase the effectiveness of certain drugs, which are used for example in tumor therapy. In addition, diamond particles often contain atomic impurities leading to characteristic discoloration such as green, purple or yellow and therefore are also called color centers. Nanoscopic diamond particles containing such color centers can be used in diagnostic medicine for the specific labeling of cells or biomolecules. Some color centers are even able to detect very small magnetic fields in their nearby environment, which will allow in the future the direct observation of biological structures at the atomic level.
The smaller, the more exciting:
Generally one can say the smaller the nanodiamonds are, the more interesting for scientists.
However, small nanodiamonds are also particularly difficult to produce. "Such small diamonds had
been prepared by grinding large stones. Production is very difficult due to the known hardness of
diamond, and even the smallest diamond ever produced, had been still too large for medical
applications. ", explains Torsten Rendler. “In order to gurantee good assimilation of the diamond
particles, they should be in the same size as for example proteins. "
The researchers made another surprising discovery. Impurity atoms, which are included in the nanodiamonds have been found to be particularly stable contrary to their expectations. While only slightly larger diamonds release foreign atoms, this was not true for the their small nanodiamonds. For the researchers this is a good news, because the impurity atoms give the nanodiamonds their special properties, that make them even more interesting for many applications.
There is one problem which cannot be solved at this moment: Too less meteorites reach the earth, so there exist only a tiny amount of such small diamond particles. The researchers are, however, already trying to develop a method to mimic the growth conditions in the meteorite on its long journey through space.
Futher Informations:
Prof. Jörg Wrachtrup, Dr. Sang-Yun Lee, Torsten Rendler, Universität Stuttgart, 3.
Physikalisches Institut, Tel. 0711/685- 65277, E-Mail: j.wrachtrup (at) physik.uni-stuttgart.de
Andrea Mayer-Grenu, Universität Stuttgart, Abt. Hochschulkommunikation, Tel. 0711/685-82176,
E-Mail: andrea.mayer-grenu (at) hkom.uni-stuttgart.de