Saratov scientists discover the healing properties of metals
Ultra-small spool
Vasily Yanchilin, newspaper "Search" No. 31/32-2013
Gold is, first of all, a precious metal. But, as they say, we love him not only for this. The chemical element, which in the Periodic Table is listed under the symbol Au, has a wide range of properties that allow it to find a variety of, sometimes very unexpected applications. For example, to detect pathological changes in cells in the body with its help and treat the patient. This opportunity opens up a new direction in biomedicine – optical nanotechnology. Our correspondent looked into the workshop of "nano-jewelers", who work, however, not only with gold, and tried to find out their secrets.
– The active use of nanoparticles is expected in the medicine of the future, – says the head of the laboratory of laser diagnostics of Technical and Living Systems of the Institute of Problems of Precision Mechanics and Control of the Russian Academy of Sciences, Head of the Department of Optics and Biophotonics of the Saratov State University named after N.G.Chernyshevsky (SSU), Doctor of Physical and Mathematical Sciences, Professor Valery Tuchin. – The dimensions of these "dust particles" are billionths of a meter, which is about a thousand times thinner than a human hair. And the configuration is the most diverse. These can be balls (solid and hollow, including composite, that is, from one or many shells of different materials), sticks, cubes, stars and other shapes. As needed, they will be made from materials such as gold, silver, iron, diamond, titanium and zinc oxides.
In medicine and cosmetology, soft particles are widely used, for example, liposomes having a lipid shell. To deliver medicines directly to the place of treatment, nanocontainers are being developed, which are a polymer shell inside which the drug is contained. The main areas of application are protection of the human body from ultraviolet radiation from the sun, optical markers (after the introduction of particles into the body, they signal the presence of pathology).
In laser and LED therapy and surgery, nanostructures are used as photon receivers. Light heats up a particle inside the cell, for example, gold, leaving the surrounding tissues cold, and the cell dies. Tiny receivers are coated with special molecules that "recognize" pathological cells, such as cancer cells, and provide selective destruction of affected areas when irradiating tissue with wide and sufficiently intense light beams. To do this, you first need to "see" the cancer cell. This vision is provided by a gold nanoparticle, strongly (resonantly) reflecting light of a certain wavelength. Then, increasing the power of the laser radiation, nanoparticles are heated to such an extent that it is possible to destroy cancer cells without harming healthy ones. There was even a new concept in medicine "theranostics" (from the words "therapy" and "diagnostics").
The same can be done with pathogenic microorganisms. Gold nanoparticles are sprayed on the surface of the wound, where bacteria are located, and irradiated with light of a certain wavelength. Under the influence of radiation, the particles are heated to a temperature harmful to microorganisms (significantly more than 100 degrees), and the harmful flora is thus neutralized. But the patient is not in danger of a burn: the wound itself heats up slightly. The main blow falls on local points.
Another example. Let's say you need to weld two very small pieces of fabric with a laser and at the same time not touch important neighboring areas. Or "brew" an unnecessary vessel so that it does not feed a cancerous tumor. In such cases, a suspension of gold nanoparticles is injected into the working area or vessel and irradiated with laser light of a certain power and wavelength. The particles are heated to the desired temperature (about 55-60 degrees), the biotissues are welded, but only those where the particles were, the rest remains cold.
– All this, as I understand it, is a background that allows you to understand what you are doing and what you have achieved?
– Yes, now about the main thing. Our research team consists of employees of the Department of Optics and Biophotonics of SSU and the scientific and educational institute of the same name, which is part of the university, as well as domestic and foreign colleagues from many countries of the world, including the USA, Great Britain, Finland, Germany, France, Italy, China. Together we are actively involved in the development of optical nanotechnology using laser and LED radiation. In Russia, our main partners are the Institute of Precision Mechanics and Control Problems (IPTMU) RAS and the Institute of Biochemistry and Physiology of Plants and Microorganisms (IBFRM) of the Russian Academy of Sciences, both are located in Saratov. The IBFRM Nanobiotechnology Laboratory under the guidance of Doctor of Physical and Mathematical Sciences Nikolay Grigoryevich Khlebtsov is developing new types of gold and other nanoparticles. IPTMU employees simulate the thermal fields that arise around them when they are introduced into the biological tissue. At SSU, we focused on developing technologies for delivering nanoparticles to the skin, adipose tissue, and liver. To do this, we use new laser methods in combination with ultrasound, measure light-induced thermal fields from nanoparticles in living tissues and cells, and study the effects of these fields on cancerous tumors and microorganisms.
Another important area related to the use of nanoparticles in medicine is studying the possibility of contactless control of them, for example, using light (laser beam), which allows you to capture a particle and make it move in the right direction.
Together with the University of Medical Sciences of Arkansas (USA), we are investigating the entire cycle from the detection of cancer metastatic cells in the circulatory and lymphatic systems of an experimental animal to their destruction by a high-power laser due to strong heating of nanoparticles bound to the cell.
How to notice a cell with nano-inclusions? As I have already said, the golden particle strongly reflects light, so it can be seen through a conventional microscope, although its actual size cannot be determined. In addition, a metal nanoparticle strongly absorbs light, which means that its heating by a laser pulse leads to the generation of a heat wave, and then sound, so we can not only see it, but also "hear" it. Often it is acoustics, not optics, that gives us information about where the desired cell is located, since light may not "get out" from the depths of the tissue.
Our joint project with the University of Oulu (Finland) and a number of other similar institutions in Sweden and Hungary is interesting. Nanotechnology specialists are developing bactericidal gypsum coatings for the walls of hospitals and public institutions. They contain titanium nanoparticles with various additives. Our task is to conduct full–scale studies of the bactericidal properties of coatings when illuminated by LED lamps operating in the visible area. This means that patients no longer have to leave the ward when it is disinfected with ultraviolet radiation. In the future, we will deal with bactericidal tables, chairs, clothes and much more. Unlike antibiotics, technologies based on nanoparticles and light do not leave microbes a chance to adapt to the impact, since it is not biochemical, but physical.
One of our projects, supported by the Russian Foundation for Basic Research and the Royal Society of Great Britain, conducted jointly with the famous Scottish University of St. Andrews, is dedicated to laser transfection of cells, that is, the introduction of DNA and other similar molecules into them. In fact, this is a surgical operation on cells. To ensure a high level of their survival after such a harsh procedure, we suggested using a low-intensity laser flash. The efficiency of the operation increases due to the use of nanoparticles attached to cell membranes. The flash, heating the particles, increases the permeability of the membrane. After that, DNA or another biologically important molecule enters the intracellular space quite easily. All other parts of the cell do not heat up, so it retains its viability.
– How are nanoassays conducted?
– It all starts with an idea. It must necessarily have a practical implementation, in our case – a medical one. Then the study of the fundamental part begins, the technology of "obtaining knowledge" is built. Now there are no simple tasks, all are complex and require the involvement of specialists from different fields. That is why we are establishing links between different laboratories in Russia and the world.
Our scientific group was created on the basis of a research university and represents an officially recognized scientific school on biophotonics, which received support in the form of a grant from the President of Russia. We attract students, postgraduates, and young scientists to carry out projects.
– How much is your work in demand?
– Our employees have written many articles, books, patents have been obtained for their developments, they defend candidate and doctoral dissertations. Publications are well cited, and monographs are in demand. We transfer new knowledge in the field of optical medical nanotechnology to students and postgraduates, train specialists of the appropriate profile from them. If we talk about the practical significance of our research, it is early diagnosis and effective treatment of cancer, the fight against pathogenic microorganisms, cell surgery and protection of the body from ultraviolet radiation.
Medical optical nanotechnology is at the initial stage of its development, however, there are already interesting results. Our immediate plans are to develop a new method of imaging malignant neoplasms on the skin using nanoparticles as markers of pathology, infrared laser radiation to heat these nanoparticles, terahertz radiation to obtain unique, specific diagnostic information. This work is already being carried out under a state contract jointly with the international educational and scientific laser Center of the Lomonosov Moscow State University.
Portal "Eternal youth" http://vechnayamolodost.ru12.08.2013