SAPPHIRE REVOLUTION

One of the promising developments in which SSU scientists participate has no analogues in the world and can become a real breakthrough in the therapy and surgery of tumors.

the Transfer of Medical and Pharmaceutical Technologies of Sechenov University. The first result of the work of this center – a catalog of technological proposals, which includes over 50 unique proposals for the medical industry, was presented at the Startup Village in Skolkovo on May 25-26.

Many of the innovative medical technologies that are presented and developed at the N.G. Chernyshevsky SSU are based on modern achievements of biophotonics. Scientists of the Scientific Medical Center, which is headed by the head of the Department of Optics and Biophotonics of the Institute of Physics, Professor, Corresponding member of the Russian Academy of Sciences V.V. Tuchin, constantly act as newsmakers of high-profile scientific events. Let's talk about some of them.

OPTICAL TECHNOLOGIES IN MEDICINE

Professor V.V. Tuchin explained how biophotonics is becoming one of the drivers of modern medicine: "Biophotonics helps to obtain information about a particular disease: the transmission of this information in the form of a signal or image is carried out using light. Some of the developments use light not only for the diagnosis and monitoring of pathologies, but also for the treatment itself.

In some cases, this happens within the framework of a single technology and the same device, when low-intensity light is used to diagnose, for example, the localization of a cancerous tumor, and the same light, but with increased power, destroys the tumor. Not only lasers are used, which has unique characteristics in terms of ultra-short pulse duration, power and coherence, but also significantly cheaper and easier-to-control LEDs. Inexpensive semiconductor lasers and LEDs have a huge niche for medical applications. The world market of biophotonics products is huge and practically not saturated. In this sense, there is a prospect for filling it.

Such SSU projects as "Analytical system for monitoring concentrations of low molecular weight substances, biomarkers and pharmaceuticals", "Detection and sorting of objects in the bloodstream", "Photoacoustic technology for early diagnosis and treatment of life-threatening diseases", "Targeted delivery of remotely controlled micro-carriers with prolonged release of drugs", "Application of phototherapy for the treatment of and prevention of dental and viral diseases", "Development of technology for creating "optical windows" in the tissues of the head" and "Methods, devices and mathematical models for analyzing the degree of interaction of the circuits of autonomic regulation of blood circulation", to varying degrees use optical technologies. They provide non-invasiveness, high speed of information collection, locality and selectivity of the impact on pathology and provide advantages for the creation of not only laboratory and clinical technologies and devices, but also medical devices for home use.

based on sapphire crystals

One of the promising developments in which SSU scientists participate is the creation of medical instruments based on profiled sapphire crystals. The website of the Russian Academy of Sciences has published an overview of the results of fundamental scientific research of academic institutions obtained in 2019-22 and ready for practical application. In particular, we are talking about the latest developments of scientists on the topic "Sapphire needle capillary irradiators for interstitial delivery of laser radiation in the therapy and surgery of tumors." These studies are the joint work of many scientific groups.

The scientific consultant of the project on the interaction of laser radiation with biological tissues is Professor Valery Viktorovich Tuchin. At our request, he spoke about the key results of the study, their practical significance and applicability.

how wonderful our… interdisciplinary union is

Traditionally, the Department of Optics and Biophotonics of SSU in cooperation with the Laboratory of Profiled Crystals of IFT RAS (Chernogolovka), the Laboratory of Broadband Dielectric Spectroscopy of IOF RAS (Moscow) and the Institute of Cluster Oncology of Sechenov University (Moscow) conducts research in various fields of science and technology, including terahertz optics, optoelectronics and biophotonics, optical coherence tomography, the creation of multimodal devices for medical diagnostics and therapy of malignant neoplasms based on profiled sapphire crystals. Joint projects are supported by various scientific foundations, including RFBR and RGNF. Both experienced specialists and young scientists, students and postgraduates of all partners take part in their implementation.

Hit the target

Among the team's developments, laser technologies can be particularly noted, which have broad prospects for use in medicine. In particular, such technologies use local heating of body tissues or the launch of a photochemical reaction using a laser source, which leads, depending on the temperature, the production of chemically active molecules and the duration of exposure, to certain changes in the irradiation site, up to the destruction of pathological tissue. This principle underlies laser precision surgery, thermotherapy and photodynamic therapy used in oncology for local destruction of neoplasms.

In addition to choosing the type and parameters of the laser source, it is also necessary to ensure accurate delivery of laser radiation to the site of exposure. To do this, an optical fiber is used in combination with special nozzles that allow it to be inserted into soft tissues without a surgical incision. Traditional laser therapy nozzles are made of quartz, which, unfortunately, does not allow them to be used repeatedly – they are damaged during phototherapy, do not withstand harsh sterilization conditions and do not allow focusing sufficiently powerful radiation into a micron-sized spot near the end of the fiber.

At the same time, thin capillary needles made of artificial sapphire do not have these disadvantages. Sapphire as a material is very attractive for biomedical applications due to the unique combination of its physical and optical properties, the ability to work in aggressive environments, including heating to high temperatures, cooling and cyclic temperature loads, chemical inertia and biocompatibility, the possibility of using various sterilization methods.

crystal needles

Due to the high hardness of sapphire, it is extremely difficult to process it by traditional mechanical methods and it is almost impossible to give a monolithic billet a complex cross-section shape, for example, to make internal channels. Nevertheless, the profiled crystal growth techniques developed and implemented under the guidance of the head of the Profiled Crystals Laboratory of the IFT RAS, Doctor of Technical Sciences Vladimir Nikolaevich Kurlov, make it possible to grow crystals with complex and even variable cross–sectional geometry, with high optical quality in volume and on the surface - directly from the Al2O3 melt, without the use of labor-intensive mechanical processing.

It is possible to obtain crystals in the form of needles with an external diameter of no more than 1.5–3.0 mm and a thin (~ 0.5 mm) hollow capillary channel inside. This channel can be closed from the tip of the sapphire needle, moreover, the tip can be given a different shape during growth or subsequent mechanical finishing. If an optical fiber is placed in the channel, then due to the high transparency of sapphire for optical radiation, such a needle can be used for laser therapy, allowing radiation to be delivered to hard-to-reach tissues and provide the necessary spatial distribution of laser illumination.

Since the inner channel is closed from the tip side, such a needle protects the fiber from direct contact with biological tissues and fluids. The surface of the sapphire needle is not subject to the formation of any defects during operation and cleaning, this reduces the possible negative consequences associated with uncontrolled overheating of the fabric, and allows you to use the needle repeatedly.

optic scalpel

The sapphire needle can be used not only for therapy and removal of neoplasms, but also for their optical diagnostics, for example, using fluorescence spectroscopy methods. In this case, the needle is connected with the source of exciting radiation and with a spectrometer analyzing the tissue response to this excitation using optical fibers located also in the inner channel. As is known, healthy tissues and neoplasms fluoresce differently, and this allows you to locally assess the condition of the area under consideration when a sapphire needle is inserted into it.

The same diagnostic principle is implemented in a multifunctional sapphire scalpel, in which several internal capillary channels are used at once to illuminate the incision site, register the fluorescent response of tissue and diffusely scattered radiation, as well as for possible coagulation of individual sections during dissection. The microfocus needle is also interesting, the shape of which allows you to concentrate radiation into a very small spot. It can be used not only for laser therapy, but also for optical stimulation of certain areas of the body.

applicators for cryogenic surgery

We also note the sapphire applicators developed for cryosurgery with optical diagnostics of the state of the tissue during its freezing. Cryosurgery is based on the rapid freezing of a part of the body's tissue to temperatures below, as a result of which necrosis occurs. Cryosurgery methods are most common in oncology, although their widespread use is still constrained by the low efficiency of visualization and control of the freezing process. The control of the change in the size of the frozen area is of great importance, since it is necessary to prevent the death of the surrounding healthy tissues, as well as to ensure complete freezing of the neoplasm area. Using the principles of diffuse scattered radiation analysis, sapphire applicators allow you to assess the depth of tissue freezing directly at the point of contact.

All these medical instruments based on profiled sapphire crystals currently have no analogues. In addition to the obvious potential for clinical use, they also allow you to combine several diagnostic and therapeutic functions in one tool. For example, it is possible to study changes in the optical properties of tissues during local exposure to high and low temperatures, laser radiation.

In April, the announcement of an article about the results of research by Russian scientists related to the creation of new medical instruments, American colleagues put on the cover of the journal "Lasers in Surgery and Medicine" in recognition of our pioneering research.

optical clearing

It should be noted that two more works published this year, carried out under the supervision of the professor ofDepartment of Optics and Biophotonics of SSU Elina Alekseevna Genina and the head of this department V.V. Tuchin, which use fiber light guides and in which the ideas of optical illumination of biological tissues were further developed in application to specific tasks of medical diagnostics and therapy.

A multimodal spectroscopic device with spatial resolution for the study of a two-layer "hybrid" model consisting of skin and fluorescent gel was developed in collaboration with the staff of the University of Lorraine within the framework of the program of the French Embassy in Moscow of double diplomas for graduate students of the Russian Federation. Sergey Zaitsev, a graduate student of SSU, became the main performer of this project.

For the first time, the technology of optical illumination of abdominal adipose tissue in vivo using hyperosmotic optical illuminating agents with a maximum illumination of up to 65% has been developed. This work was carried out by the SSU team together with the Department of Life Sciences of the Japanese company Olympus. The purpose of this study was to develop a technology for optical illumination of adipose tissue, which surrounds all internal organs and greatly interferes with surgical operations on these organs, since a doctor or robot does not see blood vessels hidden behind adipose tissue and can damage them.

SSU physicists have recently summarized their research in the field of biophotonics in a collective monograph, which was published in February this year by CRC Press under the editorship of SSU Professors V.V. Tuchin, E.A. Genina and Professor Dan Zhu of Huazhong University of Science and Technology.

The monograph discusses topical issues of optics of biological tissues and outlines the biophysical foundations and areas of application of a new method of optical illumination of biological tissues, promising for laser diagnostics, therapy and surgery. 22 chapters were written by SSU staff in collaboration with scientists from Russia and other countries, including China, the USA, Germany, France, Japan, Portugal and Iran. Scientists from China, the USA, Japan, Poland, Brazil and Canada also presented their independent studies. In total, the monograph contains 37 chapters.