Wednesday , October 27 2021

Researchers are developing a new method of producing irradiated nanomaterials for medical applications


Under the leadership of Petr Cígler from the Institute of Organic Chemistry and Biochemistry (IOCB Prague) and Martin Hrubý & # 39; from the Institute of Macromolecular Chemistry (IMC), which are part of the Czech Academy of Sciences, a team of scientists has developed a revolutionary method for the easy and inexpensive production of irradiated nanodevices and other nanomaterials suitable for use in highly sensitive diagnostics of diseases, including various cancers. Their article has recently been published in a scientific journal Nature Communications.

Diagnosing diseases and understanding the processes occurring in cells at the molecular level require sensitive and selective diagnostic tools. Today, scientists can monitor magnetic and electric fields in cells at a resolution of several dozen nanometers and with extreme sensitivity due to crystal defects in particles of some inorganic materials. Diamond is an almost ideal material for these purposes. Compared with diamonds used in jewelry, those for nanomedicine and nanomedicine applications are about a million times smaller and are synthetically produced from graphite at high pressure and temperature.

However, the pure nanodiament does not reveal much about its environment. First, its crystal lattice must be damaged under controlled conditions to produce special defects, so-called nitrogen-free centers that allow optical imaging. Injuries are most often caused by the irradiation of nanodevices with fast ions in particle accelerators. These accelerated ions are capable of knocking out carbon atoms from the nodal crystal lattice, leaving behind holes called vacancies, which at high temperature then combine with the nitrogen atoms present in the crystal as impurities. Newly created nitrogen-vacancy centers are a source of fluorescence that can then be observed. It is this fluorescence that gives nanodevices the enormous potential of applications in medicine and technology.

The basic limitation of using these materials on a larger scale, however, is the high cost and poor efficiency of ion irradiation in the accelerator, which prevents the generation of this extremely valuable material in larger quantities.

A team of researchers from several research centers headed by Petr Cígler and Martin Hrubé recently published an article in the journal Nature Communications describing a completely new method of irradiation of nanocrystals. Instead of costly and time-consuming exposure to the accelerator, scientists used radiation in the atomic reactor, which is much faster and much less expensive.

But it was not that easy. Researchers had to use the trick – in the reactor, neutron radiation divides the boron atoms into very light and fast helium and lithium ions. The nanocrystals must first be dispersed in molten boron oxide and then subjected to neutron radiation in a nuclear reactor. The capture of neutrons by the boron nuclei produces a dense stream of helium and lithium ions that have the same effect in nanocrystals as the ions produced in the accelerator: controlled crystal defect formation. The high density of this stream of particles and the use of a reactor to irradiate a much larger amount of material means that it is easier and cheaper to produce several tens of rare nanomaterials at the same time, which is about a thousand times more than scientists. so far it has been achieved thanks to comparable radiation in accelerators.

The method proved to be effective not only in creating defects in the network of nanodevices, but also in another nanomaterial – silicon carbide. For this reason, scientists hypothesize that the method could find a universal application in the production of nanoparticles with specific defects on a large scale.

The new method uses the principle used in boron neutron capture (BNCT) therapy in which patients are given a boron compound. After collecting the compound in the tumor, the patient receives radiation therapy with neutrons, which split it into helium and lithium ions. Then they destroy cancer cells in which boron accumulated. This principle, taken from the experimental treatment of cancer, opened the door for the efficient production of nanomaterials with unique potential for applications in, among others, cancer diagnostics.

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