Для лазерного скальпеля разработан метод контроля температуры на торце его оптоволокна с конвертером путем возбуждения в нем ультразвуковых импульсов продольных и изгибных волн и измерения времени задержки их распространения. Для возбуждения в сердцевине оптоволокна ультразвуковых волн на частоте 1.1 МГц с помощью пьезоэлемента из ЦТС-19 использовался метод клина. В качестве материала клина использовался сплав Розе, а для его закрепления на защитной оболочке оптоволокна − навитая на нем тонкая проволока. Измерение задержек ультразвуковых импульсов осуществлялось методом стробирования сигналов для дальностей локации, соответствующих отражению от рабочего торца оптоволокна. При превышении установленных значений температур вырабатывается цифровой сигнал для звуковой сигнализации и для схемы управления лазером с целью уменьшения мощности излучения.

The effect of gamma irradiation therapy on the collagen structure of rat tail tendon has been studied. The decrease in the denaturation enthalpy and increase in trypsin susceptibility was related with a damage of triple helical macromolecules (19±7%). Destabilized collagen fraction and the alteration in biopolymers-water interaction were observed by differential scanning calorimetry. The loosing of secondary and tertiary fiber bundles was revealed by second harmonic generation microscopy. No significant degradation of anisotropic properties and tissue architectonics was revealed by cross-polarization optical coherent tomography technique. The instant response of collagen matrix on ionized radiation is related to degradation of collagen at the molecular level of organization.

For the first time authors conducted a complex assessment of age-related morphological and functional peculiarities of skin of different anatomic areas. Study sample included 43 healthy volunteers 4 to 74 years old. Structural parameters of skin were assessed using optic cogerent tomography equipped with removable flexible sonde with microscanner with longitudinal and transverse resolution 20 µm engineered and produced in Institute of applied physics RAS (Nizhniy Novgorod).

The method of fluorescent microscopy is developed based on employment of a single-mode fibreoptic channel to provide high spatial resolution 3D images of large cleared biological specimens using the 488-nm excitation laser line. The transverse and axial resolution of the setup is 5 and 13 μm, respectively. The transversal sample size under investigation is up to 10 mm. The in-depth scanning range depends on the sample transparency and reaches 4 mm in the experiment. The 3D images of whole mouse organs (heart, lungs, brain) and mouse embryos obtained using autofluorescence or fluorescence of exogenous markers demonstrate a high contrast and cellular-level resolution.

The paper presents the results from a study of the breast oxygen status by diffuse optical tomography (DOT). Detection of breast tissue at wavelengths of 684, 794, and 850 nm could provide information on the distribution of basic tissue chromophores: oxygenized and deoxygenized hemoglobin. Normal breast tissue was characterized by the even distribution of these compounds and stabilization of their level. In breast cancer, the distribution of oxyand deoxyhemoglobin was noted for uneven distribution and blood oxygen saturation was lower in the projection of a tumor nodule. The blood oxygen saturation data obtained by DOT demonstrate physiological differences between normal and tumor tissues in different tumor areas.

Collagen degradation caused by IR laser irradiation in ligament tissues was studied by thermal analysis and cross-polarization optical coherent tomography. It was found that, at 60°C, laser-induced modification of the quasi-crystalline packing of ordered collagen fibers occurred without the helix-coil molecular conformation transition. It was shown that, for uniaxial tension of ligaments, laser irradiation caused serious distortions in the structure of collagen and increased the fraction of macromolecules in the random coil state. It was assumed that the thermomechanical effect of laser treatment during laser heating played an important role.

The amino acid composition, thermal behavior and birefringence properties of thyroid cartilage tissues have been studied. A collagen component in perichondrium consists of type-I and type-II collagens whose fibers form a highly ordered anisotropic structure with a birefringence of 4.75 × 10−3 and a melting (denaturation) temperature of 65°C. The hyaline constituent, which is visualized as a quasi-anisotropic medium, contains of only type-II collagen, which does not denature in intact tissues at temperatures up to 100°C. However, in tissues whose proteoglycane subsystem is damaged by trypsin, the denaturation of collagen takes place at 60°C. In the integral perichondrium-hyaline system, the temperature of collagen denaturation in the perichondrium reaches 75°C, which indicates the immobilization of collagen in this tissue by the extracellular matrix of the hyaline constituent.

In vivo study of gold nanoparticles effects on images obtained by optical coherence tomography (OCT) was performed. Colloidal solution of gold nanoparticles was applied on the surface of animal skin one or several times. It has been shown that gold nanoparticles (having an average diameter of 50 nm) penetrate into the dermis and improve visualization of some histological structures on the OCT-images. Hair bulbs and the surface part of the dermis became clearly visible on the OCT-images of the skin after single application of colloidal gold. The most contrasted images were obtained 2.5 h after gold nanoparticles application. The presence of nanoparticles in the skin was confirmed by electron microscopy.