Laser fabrication of composite layers from biopolymers with branched 3D networks of single-walled carbon nanotubes for cardiovascular implants
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15.03.2021 |
Gerasimenko A.Y.
Kurilova U.E.
Savelyev M.S.
Murashko D.T.
Glukhova O.E.
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Composite Structures |
10.1016/j.compstruct.2020.113517 |
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© 2020 Elsevier Ltd A laser technology has been developed for fabricating structures from composite layers based on biopolymers: albumin, collagen, and chitosan with single-walled carbon nanotubes (SWCNT). The structures are intended for cardiovascular devices and tissue-engineered implants. This is evidenced by the results of studies. The composite layers were fabricated due to the phase transition of biopolymers and SWCNT aqueous dispersion under the influence of laser pulses. At the same time branched 3D networks of SWCNT were formed in the biopolymer matrix. The threshold energy fluence of laser pulses was determined (0.032–0.083 J/cm2) at which a bimodal distribution of pores was observed. The calculation of contact resistances between nanotubes at percolation units of 3D networks (20–100 kOhm) was carried out. Composite layers fabricated by laser demonstrated conductivity values that were higher (12.4 S/m) than those for layers by thermostat (4.7 S/m). The maximum hardness of the composite layers with SWCNT (0.01 wt%) by laser was 482 ± 10, 425 ± 10, and 407 ± 15 MPa for albumin, collagen and chitosan, respectively. The hardness of the thermostat layers was less than 100 MPa. The viability of endothelial cells in composite layers was improved. The composite layers ensured a normal level of hemolysis during interaction with erythrocytes.
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Heart phantom with electrical properties of heart muscle tissue
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01.09.2018 |
Korn L.
Lyra S.
Rüschen D.
Pugovkin A.
Telyshev D.
Leonhardt S.
Walter M.
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Current Directions in Biomedical Engineering |
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© 2018 Leonie Korn et al. The weakened heart is supported by a left ventricular assist device (LVAD) to supply the heart muscle with oxygenated blood. In case the heart muscle recovers during LVAD therapy, the patient has to be weaned from the device. To date, there is no adequate method to detect heart muscle recovery in LVAD therapy. In order to establish a novel method based on the measurement of electric conductivity, this study presents a silicone model of a ventricle mock-up to simulate the electrical properties of cardiac muscle tissue. Previously, it has been shown that the electrical properties of myocardial tissue change during ischemia, so that these changes are a possible estimate for measuring the condition of myocardial tissue. To this purpose, this study presents a casting process for a ventricle model and describes the materials used to imitate the electrical properties of the heart muscle to obtain conductive material. Initial results showed that the higher the carbon concentration in the silicone, the higher the conductivity of the silicone samples. The measurements were performed at different frequencies and the samples were analyzed for homogenization.
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Stimulation of the specific conductivity of the biocompatible nanomaterial layers by laser irradiation
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01.01.2018 |
Ichkitidze L.
Glukhova O.
Savostyanov G.
Gerasimenko A.
Podgaetsky V.
Selishchev S.
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Proceedings of SPIE - The International Society for Optical Engineering |
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© 2018 SPIE. The conductivity of layers (thickness ∼ 0.5-20 μm) of composite nanomaterials consisting of bovine serum albumin (BSA) with single-walled carbon nanotubes (SWCNTs) has been studied. The BSA/SWCNT composite nanomaterial was prepared according to a route map, some steps of which are: the preparation of an aqueous dispersion based on BSA and SWCNT; preparation of substrates; deposition of BSA/SWCNT dispersion on substrates; application of water paste from SWCNT on substrates; irradiation of layers by lasers when they were in a liquid state; drying of samples; carrying out electrical and temperature measurements. Half of the layer was covered with a light-tight hollow box and the other half of the layer was laser irradiated. The laser irradiation of the layer was carried out for about 20 sec, at which time the layers completely became dry, while the other half of the layer remained in liquid. Conductivity was increased (70 ÷ 650) % by laser irradiation of the layers when they were in the liquid state. Maximum values of specific conductivity for BSA/SWCNT-1 S/m layers, and for layers SWCNT - 70 kS/m. The investigated electrically conductive layers of 99 wt.% BSA/0.3 wt.% SWCNT are promising for medical practice.
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Electrical conductivity of the nanocomposite layers for use in biomedical systems
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01.01.2018 |
Ichkitidze L.
Gerasimenko A.
Podgaetsky V.
Selishchev S.
Dudin A.
Pavlov A.
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Materials Physics and Mechanics |
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4 |
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© 2018, Peter the Great St. Petersburg Polytechnic University. Nanocomposite layers consisting of an acrylic paint and single-walled carbon nanotubes (∼1.5 wt.%) have been investigated. The investigated samples had a disk shape with a diameter of 20-30 mm and a thickness of 2-50 μm. After exposure in water for 350 h, the layer mass remained almost invariable (a mass loss of ≤ 1.5%) and the layer samples exhibited high adhesion to glass substrates and a conductivity of ∼ 40 S/m. The layers consisting of the nanotubes and acrylic paint exfoliated from the substrates for ∼1 h. After heat treatment at a temperature of 140 °C, all the layers exhibited a semiconductor-type temperature dependence of the resistance. The prospects of using these layers in various medical products, e.g. implants for wireless energy transmission, have been discussed.
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