U. E. Kurilova

Investigation of cell proliferative activity on the surface of the nanocomposite material produced by laser radiation

A new method for the formation of composite nanomaterials based on multi-walled and single-walled carbon nanotubes (CNT) on a silicon substrate has been developed. Formation is carried out by ultrasound coating of a silicon substrate by homogenous dispersion of CNTs in the albumin matrix and further irradiation with the continuous laser beam with a wavelength of 810 nm and power of 5.5 watts. The high electrical conductivity of CNTs provides its structuring under the influence of the laser radiation electric field. The result is a scaffold that provides high mechanical strength of nanocomposite material (250 MPa). For in vitro studies of materials biocompatibility a method of cell growth microscopic analysis was developed. Human embryonic fibroblasts (EPP) were used as biological cells. Investigation of the interaction between nanocomposite material and cells was carried out by optical and atomic force microscopy depending on the time of cells incubation. The study showed that after 3 hours incubation EPP were fixed on the substrate surface, avoiding the surface of the composite material. However, after 24 hours of incubation EPP fix on the sample surface and then begin to grow and divide. After 72 hours of incubation, the cells completely fill the sample surface of nanocomposite material. Thus, a nanocomposite material based on CNTs in albumin matrix does not inhibit cell growth on its surface, and favours their growth. The nanocomposite material can be used for creating soft tissue implants

The method of laser forming of nanocarbon biocompatible coatings for implants

The work is devoted to laser method of biocompatible coatings forming to create implants of the human body ligaments. Coating is a carbon nanotubes scaffold formed in the water-protein dispersion by the electric field of the laser radiation. Study has been conducted on the structure and properties of carbon nanotubes coatings and proliferative activity of biological cells on its surface.

Laser Technology of Designing Nanocomposite Implants of the Knee Ligaments

We describe a laser method for constructing a biocompatible implant of the knee ligaments based on synthetic-braided fiber structure of polyethylene terephthalate (PET) coated with a nanocomposite coating. A coating based on albumin aqueous dispersion of carbon nanotubes (CNTs) was applied to the synthetic fibers using ultrasound and then formed by laser evaporation of the aqueous dispersion component. The structure of the nanocomposite implants was studied by optical and atomic force microscopy. Composite implant based on single-walled CNTs (SWCNTs) contains pores with a diameter of 10–20 nm, and based on multi-walled CNTs (MWCNTs)—40–60 nm. We conducted in vitro studies of proliferative activity of human fibroblast cells (HFb) during their colonization on the surface of the implant and into the space between synthetic fibers. The highest value of the HFb proliferation was observed on the implant based on MWCNTs with a large pore size and amounted to 55.435 pcs., in contrast to the implant based on SWCNTs (54.931 pcs.) and control one (54.715 pcs.), as shown by fluorescence microscopy and MTT test. A histological study of the interaction of the nanocomposite implant implanted into rabbit knee joint with bone canal was carried out. The bone germination in the implantation area at 2, 4 and 8 weeks after surgery was shown.

Structure and Biochemical Study of Nanocomposite Bioconstruction for Restoration of Bone-cartilaginous Defects

Porous and strong nanocomposite bioconstructions were formed by laser evaporation of an aqueous dispersion of carbon nanotubes in a protein matrix. The homogeneous dispersion was exposed to laser irradiation to create solid constructions. Continuous laser radiation with a wavelength of 970 nm and a power of 5-7 W was used. The porosity of nanocomposite bioconstructions was studied by the method of lowtemperature nitrogen porosimetry and X-ray microtomography, the tensile strength and relative elongation of bioconstructions were evaluated, and their biocompatibility was tested in vitro. It was found that with an increase of the carbon nanotube’s concentration, a slight decrease in strength (3-15 %), a decrease in the pore size (20- 40 %), and an increase in the degree of deformation (10-12 %) were observed. At the same time, the mechanical parameters of the bioconstructions met the requirements for the materials for the restoration of bone-cartilaginous defects. Using optical microscopy and the MTT-test, proliferative activity and structural features of bone tissue cells on the surface of nanocomposite bioconstructions were evaluated. Studies have shown no toxic or inhibitory effect on cells. The results of the studies can talk about the advantage of nanocomposite bioconstructions using as an implant material for improving the growth of biological cells and regenerating damaged biotissues. Keywords: Nanocomposites, laser radiation, mechanical properties, porosity, X-ray microtomography, biocompatibility

Laser nanocomposites based on proteins and carbon nanotubes for restoration of biological tissues

The study of structural properties of nanocomposites, based on different types of single walled carbon nanotubes (SWCNTs) and proteins (albumin, collagen), was carried out. The binding of protein molecules to the carbon component was described by Raman spectroscopy. Complex analysis of the structure and microporosity of nanocomposites was performed by the X-ray microtomography. The nanoporosity study was carried out using the low-temperature nitrogen porosimetry method. Samples based on SWCNTs with smaller size had the most homogeneity. With an increase in the concentration from 0.01 to 0.1 %, the mean micropore size increased from 45 to 93 μm, porosity in general increased from 16 to 28 %. The percentage of open pores was the same for all samples and was 0.02. As it was shown by Raman spectroscopy the protein component in nanocomposites has undergone irreversible denaturation and can act as a biocompatible binder and serve as a source of amino acids for biological tissues. These nanocomposites are bioresorbable and can be used to repair cartilage and bone tissue. This is especially important in the treatment of diseases of hyaline cartilage and subchondral bone.

Threshold effect in properties of limiters for high-intensity laser radiation

Creation of limiters for intensive laser radiation requires the development of effective methods for testing materials to determine the nonlinear optical parameters characterizing their properties. The limiting threshold, linear and nonlinear absorption coefficients can be determined not only from data of Z-scan with open aperture, but also with the help of a fixed location of the limiter. The use of this method makes it possible to determine the output characteristic of the studied material from which nonlinear optical parameters can be calculated. Characteristics of carbon nanotubes and graphene oxide in water were obtained with the fixed location of the limiter. The experiments were performed using an Nd:YAG laser that generates pulses of 16 ns duration at a wavelength of 532 nm with the linearly polarized laser beam in the horizontal plane and a shape closed to Gaussian type. Theoretical curves for method of fixed location of the sample according to threshold model was calculated and compared with the experimental data. Normalized weakening coefficients, limiting threshold, linear and nonlinear absorption coefficients were found for studied dispersions and calculation of Z-scan with open aperture was made. The value of normalized weakening coefficient was higher in dispersed medium of SWСNTs with water (Knorm≈20) in comparison with oxide graphene in water (Knorm≈14). The dependences of normalized weakening coefficient bias input energy were approximately linear in both cases.

The technology of laser fabrication of cell 3D scaffolds based on proteins and carbon nanoparticles

The technology of cell 3D scaffolds laser fabrication is developed. 3D scaffolds are designed to repair osteochondral defects, which are poorly restored during the organism’s life. The technology involves the use of an installation, the laser beam of which moves along a liquid nanomaterial and evaporates it layer by layer. Liquid nanomaterial consists of the water-protein (collagen, albumin) suspension with carbon nanoparticles (single-walled carbon nanotubes). During laser irradiation, the temperature in the region of nanotubes defects increases and nanotubes are combined into the scaffold. The main component of installation is a continuous laser operating at wavelengh of 810 nm. The laser beam moves along 3 coordinates, which makes it possible to obtain samples of the required geometric shape. The internal and surface structure of the samples at the micro- and nanoscale levels were studied using the X-ray microtomography and scanning electron microscopy. In vitro studies of cell growth during 48 and 72 hours demonstrated the ability of cell 3D scaffolds to support the proliferation of osteoblasts and chondroblasts. Using fluorescence and atomic force microscopy, it was found that the growth and development of cells on a sample with a larger concentration of nanotubes occurred faster compared to samples with a smaller concentration of nanotubes.

The study of the geometric parameters and zeta potential of gold nanorods and nanostars based on light scattering methods

Samples of liquid dispersions of gold nanorods and nanostars with different size and shape were synthesized and studied based on dynamic light scattering, polarization measurements, electrophoretic light scattering.