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The effect of ultrashort laser radiation parameters on the process of biomaterial formation based on dispersed media of bovine serum albumin and carbon nanotubes was studied. It is noted that, in contrast to the use of continuous laser radiation of comparable power, the composite nanomaterial is formed when lower temperatures are reached, which provides additional advantages and a smaller change in the protein structure. This effect can also be associated with a pulse repetition rate of 80 MHz, in the interval, which is about 12.5 ns, partial cooling of the material can occur, while this effect is sufficient for the formation of a biomaterial. The hardness of this material is comparable to that of native tissue. A strong twofold change in the elasticity of such a material in comparison with drying in air indicates the formation of an inner framework of carbon nanotubes. The possibility of this effect is also confirmed by spectral studies, according to which, at the used wavelength of 810 nm, the radiation is absorbed mainly by carbon nanotubes and only as a result of heat transfer is transmitted to bovine serum albumin and is spent on water evaporation. In vitro studies of cell growth in the presence of biomaterial were carried out by quantitative (MTT test) and qualitative (microscopy) methods. It was found that the number of cells grown on the composites exceeds the number of cells in the control after 72 hours of incubation. The cells on the composites formed a monolayer, their morphology does not differ from the morphology of the cells in the control. In vitro studies indicate a positive effect of the biomaterial on cell adhesion and proliferation and, consequently, on the possibility of their use for tissue regeneration.

The structural parameters and vibrational IR and Raman spectra of the molecular unit of the chitosan polymer, chitosan dimer, and chitosan dimer in complex with SWCN fragment were calculated. It is shown that the interaction of the chitosan dimer with SWCNTs leads to a change in the valence angle of the COS linking the elementary units of the chitosan biopolymer and the valence angle of the hydrogen bond bridge C ... .NO. In the IR spectra, an increase in the intensity of the absorption bands in the region of ~1000 cm-1 is observed, and in the Raman spectra – an increase in the intensity of the lines in the low-frequency region of ~400-600 cm-1.

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.

Laser radiation limiters can be made on the basis of working substances, which have strong nonlinear effects after reaching a certain critical value (threshold limiting). Thus, it becomes possible to obtain a high transmission for a safe beam and a sharply reduced transmission for a hazardous beam. To determine the nonlinear and linear optical properties of these materials there were carried out comprehensive spectroscopic studies, experiments by Z-scan methods with an open aperture and a fixed location of the limiter. Working substances was developed which is suspension of conjugates J-type phthalocyanine dimers Zn or Mg with single-walled carbon nanotubes (SWCNTs) in water. Created conjugates can be used not only for protecting eyes and light-sensitivity elements, but for forming three-dimensional tissueengineered structures. Using conjugates J-type phthalocyanine dimers Zn and Mg with SWCNTs will increase the optical absorption in the wavelength range of laser processing by reducing the thermal effect on other substances in the composition of this structure. The Nd:YAG laser was used as the laser radiation source for generating pulses of 16 ns duration at a wavelength of 532 nm with the linearly polarized laser beam in the horizontal plane and a shape of Gaussian type. The threshold of limiting, linear and nonlinear absorption coefficients were determined by output characteristic, that was obtained by fixed location of the limiter. Created working substances have values of the following order: linear absorption coefficient ~ 3 cm-1 for layer of 0.2 cm thickness, low limiting threshold ~ 1 MW·cm-2 and high value of the nonlinear absorption coefficient ~ 550 cm GW-1 . Knowing the nonlinear optical parameters, Z-scan data with an open aperture can be calculated for comparison with experimental data.

The results of experimental creation of nanocomposites using femtosecond laser are presented. We have theoretically proved the formation of a carbon nanotube frame in a protein matrix during laser structuring of single-walled carbon nanotubes. We have selected the technological parameters of synthesis of nanocomposites, which provide the proliferation of living cells.

Creation of effective means of protection from laser radiation of high power requires the development of optical materials (working substance), with their transparence being decreased sharply above a certain critical value of the laser intensity due to the appearance of non-linear optical properties (limiting threshold). Based on the threshold model, the working substance of the optical limiter was characterized. Experimental data of z-scan with open aperture are used to determine the nonlinear optical parameters of solutions of dimeric phthalocyanine complexes of Mg and Zn of J-type in tetrahydrofuran (THF) and thin films of their conjugates with single-walled carbon nanotubes (SWCNTs). The output characteristic (output (peak) fluence vs input (peak) fluence), that describes the basic properties of optical limiters, was obtained with the fixed location of the optical limiter. Dimeric phthalocyanine complexes were found to have low limiting threshold ~ 2 MW·cm-2 and high value of the nonlinear absorption coefficient ~ 330 and 370 cm GW-1, respectively. Conjugates of these dimeric phthalocyanines with SWCNTs have been produced for the improving of the limiting parameters and increasing of the optical nonlinearity. Size of J-type dimeric phthalocyanine complexes of Mg and Zn were determined by the scanning electron microscopy (SEM). The atomic force microscopy (AFM) allowed to determine the dimensions of nanotubes. The structure parameters, such as diameter and defects as well as the strength of aggregates were estimated with the Raman spectroscopy. For our experiments, the lens with a focal length of 20 cm was used. As the laser radiation source, the Nd:YAG laser was used to generate 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. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

3-D bioconstructions were created using the evaporation method of the water-albumin solution with carbon nanotubes (CNTs) by the continuous and pulsed femtosecond laser radiation. It is determined that the volume structure of the samples created by the femtosecond radiation has more cavities than the one created by the continuous radiation. The average diameter for multi-walled carbon nanotubes (MWCNTs) samples was almost two times higher (35-40 nm) than for single-walled carbon nanotubes (SWCNTs) samples (20-30 nm). The most homogenous 3-D bioconstruction was formed from MWCNTs by the continuous laser radiation. The hardness of such samples totaled up to 370 MPa at the nanoscale. High strength properties and the resistance of the 3-D bioconstructions produced by the laser irradiation depend on the volume nanotubes scaffold forming inside them. The scaffold was formed by the electric field of the directed laser irradiation. The covalent bond energy between the nanotube carbon molecule and the oxygen of the bovine serum albumin aminoacid residue amounts 580 kJ/mol. The 3-D bioconstructions based on MWCNTs and SWCNTs becomes overgrown with the cells (fibroblasts) over the course of 72 hours. The samples based on the both types of CNTs are not toxic for the cells and don't change its normal composition and structure. Thus the 3-D bioconstructions that are nanostructured by the pulsed and continuous laser radiation can be applied as implant materials for the recovery of the connecting tissues of the living body.

Laser welding device for biological tissue has been developed. The main device parts are the radiation system and adaptive thermal stabilization system of welding area. Adaptive thermal stabilization system provided the relation between the laser radiation intensity and the weld temperature. Using atomic force microscopy the structure of composite which is formed by the radiation of laser solder based on aqua- albuminous dispersion of multi-walled carbon nanotubes was investigated. AFM topograms nanocomposite solder are mainly defined by the presence of pores in the samples. In generally, the surface structure of composite is influenced by the time, laser radiation power and MWCNT concentration. Average size of backbone nanoelements not exceeded 500 nm. Bulk density of nanoelements was in the range 10 6 -10 8 sm -3 . The data of welding temperature maintained during the laser welding process and the corresponding tensile strength values were obtained. Maximum tensile strength of the suture was reached in the range 50-55°C. This temperature and the pointwise laser welding technology (point area ~ 2.5mm) allows avoiding thermal necrosis of healthy section of biological tissue and provided reliable bonding construction of weld join. In despite of the fact that tensile strength values of the samples are in the range of 15% in comparison with unbroken strips of pigskin leather. This situation corresponds to the initial stage of the dissected tissue connection with a view to further increasing of the joint strength of tissues with the recovery of tissue structure; thereby achieved ratio is enough for a medical practice in certain cases.

Dispersive and composite nanomaterials based on multi-walled and single-walled carbon nanotubes and its conjugates with dye of zinc phthalocyanine were produced. The composition and the structure of dispersive and composite materials were investigated using analytical methods of spectroscopy and microscopy. Nonlinear characteristic of nanomaterials of limiters by direct nonlinear scanning and Z-scan method were investigated. Studies suggest the possibility of using such nanomaterials in laser intensity limiters. Proposed threshold model characterizing limiters of powerful laser radiation takes into account the threshold nature of nonlinear interaction of irradiation with the nonlinear material. Threshold effect of nonlinear interaction of laser irradiation with several nonlinear material based on multi-walled and single-walled carbon nanotubes was experimentally found. It was shown that threshold model fit better with experimental data of Z-scan.