Petr Cígler from the Czech Institute of Organic Chemistry and Biochemistry (IOCB Prague) and Martin Hrubý from the Czech Institute of Macromolecular Chemistry (IMC) recently led a group of researchers in the development of a new method of the cheap and easy creation of irradiated nanodiamonds and other nanomaterials. These new materials are useful in the diagnosis of diseases including several types of cancer. The article detailing the results of their efforts was just published in the journal Nature Communications.
Sensitive and selective diagnostic instruments are required for diagnosing many diseases. Scientists are now able to track the behavior of magnetic and electric fields in living cells at a resolution of a few dozen nanometers. (A nanometer is one millionth of a meter.) They accomplish this by utilizing crystal defects in some types of inorganic materials. It turns out that nanodiamonds produced from graphite with very high temperatures and pressures are ideal for this purpose.
Pure nanodiamonds cannot be used for diagnostics. In order to be applied to diagnostics, nanodiamonds must endure damage to their crystal lattices. Special defects called nitrogen-vacancy centers allow optical imaging. The usual way to generate these defects is to irradiate nanodiamonds with fast ions from particle accelerators. The fast ions knock carbon atoms out of the nanodiamonds crystal lattice and leave vacancies. Then nitrogen atoms which contaminate the nanodiamonds combine with the vacancies to create nitrogen-vacancy centers. These nitrogen-vacancy centers can fluoresce which results in visible light. This property can be used in diagnosis of diseases.
The current system of generating defects in nanodiamonds is very expensive and very inefficient. This means that large quantities of these useful nanodiamonds cannot be produced. Now the research team from the Czech Republic has developed a new technique for the production of defects in nanodiamonds. Their new technique relies on the use of a nuclear reactor to irradiate the nanodiamonds to produce the desired defects.
To produce the necessary defects, the nanodiamonds must first be dispersed in molten boron oxide. Then the molten boron is placed in a nuclear reactor and subjected to neutron bombardment. This results in the generation of a shower of helium and lithium ions which, in turn, create the desired defects in the nanodiamonds. This process allows the creation of one thousand times as many nanodiamonds containing nitrogen-vacancy centers
in a single batch as can be produced by the old method. Silicon carbide crystals can also have defects created by this method. In fact, it may turn out that the new method created by the Czech researchers can be used as a general technique for the controlled production of defects in a wide variety of crystals.
The ability to inexpensively produce large quantities of nanodiamonds with nitrogen-vacancy centers will permit a much wider usage of these special nanodiamonds in the diagnosis of many types of cancers. This will lower the cost of diagnosis and will allow many people with developing cancers to be diagnosed in time for proper life-saving treatment.