Effects of infrared and ultraviolet radiation on the viability of cells immobilized in porous TiNi-based alloy scaffold

Сell responses to electromagnetic radiation are due to many factors including the cellular microenvironment. The aim of the present study was to explore the effects of ultraviolet (UV) and infrared (IR) irradiation of low intensity on cultured cells derived from different biological tissues (spleen, bone marrow, and Ehrlich's adenocarcinoma), which were immobilized in a porous TiNi-based alloy scaffold. Accordingly, the following objectives were set: i) to evaluate the impact of low-intensity radiation on cell suspensions, and ii) to carry out a comparative analysis of the viability of cells immobilized in porous TiNibased alloy and IR- and UV-irradiated. The data show that the extracellular environment of bone marrow, tumor and spleen cel

Biocompatibility assessment of coatings obtained in argon and nitrogen atmospheres for TiNi materials

This work aims to study the cytocompatibility of protective coatings obtained in argon and nitrogen atmospheres on a TiNi surface. Particular attention is paid to comparing the interaction of cell culture with coatings and an uncoated TiNi sample, using for comparison the number of viable cells on the surface, the phase composition, structure, wettability, surface charge and topography. The Ti/Ni/Ti nanolaminate was deposited on a TiNi substrate by magnetron sputtering. Reaction annealing of Ti/Ni/Ti nanolaminate on a TiNi substrate, when heated to 900 ◦C in argon, leads to the formation of a dense two-layer coating 2.0–2.1 µm thick: layer I (TiO + Ti2N), layer II (Ti4Ni2 O(N)). Reaction annealing in nitrogen leads to the formation of a thin three-layer nanocoating 250 nm thick: I (TiO2 + TiN), II (Ti4Ni2N(O) + Ti3Ni4), III (TiN). The coating synthesized in nitrogen is more favorable for cell attachment and proliferation because of the moderately hydrophilic rough surface and mixed phase composition of titanium nitrides and oxides

Properties of Coatings Based on Calcium Phosphate and Their Effect on Cytocompatibility and Bioactivity of Titanium Nickelide

Coatings based on calcium phosphate with thicknesses of 0.5 and 2 μm were obtained by high-frequency magnetron sputtering on NiTi substrates in an argon atmosphere. The coating was characterized using X-ray diffraction, scanning electron microscopy, atomic force microscopy, and in vitro cytocompatibility and bioactivity studies. A biphasic coating of tricalcium phosphate (Ca3(PO4)2) and hydroxyapatite (Ca10(PO4)6(OH)2) with a 100% degree of crystallinity was formed on the surface. The layer enriched in calcium, phosphorus, and oxygen was observed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Scanning electron microscopy showed that the surface structure is homogeneous without visible defects. The 2 µm thick coating obtained by sputtering with a deposition time of 4 h and a deposition rate of 0.43 µm/h is uniform, contains the highest amount of the calcium phosphate phase, and is most suitable for the faster growth of cells and accelerated formation of apatite layers. Samples with calcium phosphate coatings do not cause hemolysis and have a low cytotoxicity index. The results of immersion in a solution simulating body fluid show that NiTi with the biphasic coating promotes apatite growth, which is beneficial for biological activity

Microstructural characterization, wettability and cytocompatibility of gradient coatings synthesized by gas nitriding of three-layer Ti/Ni/Ti nanolaminates magnetron sputtered on the TiNi substrate

In the study, gradient coatings with a nanometer thickness were successfully synthesized from Ti/Ni/Ti nanolaminates on the TiNi substrate in a nitrogen atmosphere at 900 °C. A technique for producing a gradient coating includes magnetron sputtering of Ti/Ni/Ti nanolayers with a total thickness of 75 nm and 150 nm on a TiNi substrate and further synthesis of the coating by annealing the sample in a nitrogen atmosphere. The developed technique allows to form stable phases of titanium nitride and intermetallic oxynitrides, which are a reliable barrier to nickel diffusion from the substrate to the surface. No nickel was found on the surface of the synthesized coatings. In the synthesized coating from 150 nm thick nanolaminate, these barriers are Ti4Ni2(N,O) and TiN phases. In the synthesized coating from 75 nm thick nanolaminate, these barriers are two continuous TiN layers. The cytocompatibility of the coating synthesized from Ti/Ni/Ti nanolaminates with a total thickness of 150 nm was positively affected by a mixed-phase composition of titanium nitrides and oxides, moderate roughness and hydrophilicity

Softening Effects in Biological Tissues and NiTi Knitwear during Cyclic Loading

Samples of skin, tendons, muscles, and knitwear composed of NiTi wire are studied by uniaxial cyclic tension and stretching to rupture. The metal knitted mesh behaves similar to a superelastic material when stretched, similar to soft biological tissues. The superelasticity effect was found in NiTi wire, but not in the mesh composed of it. A softening effect similar to biological tissues is observed during the cyclic stretching of the mesh. The mechanical behavior of the NiTi mesh is similar to the biomechanical behavior of biological tissues. The discovered superelastic effects allow developing criteria for the selection and evaluation of mesh materials composed of titanium nickelide for soft tissue reconstructive surgery

Structure and phase composition of a coating synthesized from Ti-Nni-Ti laminate on TiNi substrate

A gradient magnetron-sputtered three-layer laminated Ti–Ni–Ti coating is formed by the method of reactio

Evaluation of allogenic hepato-tissue engineered in porous TiNi-based scaffolds for liver regeneration in a CCl4-induced cirrhosis rat model

The study aimed to explore the in vivo applicability of intracorporeal constructions with hepatocytes cultured in the porous TiNi-based scaffold (PTNS). We also sought to determine whether application of hepatocytes cultured in the PTNS was superior to sham operation or simple hepatocyte injection in terms of restoration of liver functions and survival time in a CCl4-induced hepatitis rat model. Using 12 animals, image analysis of SEM data of in vivo hepatocyte evolution in the PTNS was carried out. In addition, 200 animals were assigned to explore the experimental groups as follows: (1) Group I, control group; (2) Group II, animals with toxic hepatitis; (3) Group III, animals with toxic hepatitis followed by implantation of cell-free PTNS (sham-surgery); 4) Group IV, animals with toxic hepatitis followed by infusion of hepatocytes only (15 × 106 cells ml−1); 5) Group V, animals with toxic hepatitis followed by implantation of hepatocytes cultured in the PTNS. In the SEM analysis, hepatocytes demonstrated good adhesion and proliferation in the pore space of the PTNS. Moreover, mature tissue comprising both colloidal and fibrous components filled the pore body by 95% in 28 days. Concerning restoration of liver function, Group V showed a significant reduction of serum alanine aminotransferase level compared to Group II. Group IV also showed a significant decrease in ALT level at 15 days. However, the level of ALT increased at 30 days, and the level was similar with results of the group II. This situation probably was caused by a short-term effect of hepatocyte injection only. The change patterns of serum protein, lactate, albumin, fibrinogen, and total bilirubin levels were similar to the results of ALT. The survival time of animals was significantly longer in Group V. These findings showed possible abilities of the PTNS as a scaffold to support the hepatocellular metabolism. Overall, this study sheds a different light on how the implantable «auxiliary liver» by engrafting the cultured PTNS substitutes the missing hepatic function without the need to replace the whole liver

Metal-glass-ceramic phases on the surface of porous TiNi-based SHS-material for carriers of cells

Using the methods of SEM, EDS, and optical microscopy, a large number of non-metallic inclusions are revealed on the pore surface of a TiNi-based SHS-alloy. According to the XRD and EDS data, the surface is chemically and structurally inhomogeneous and its composition is close to that of a Ti4Ni2(O,N,C) intermetallic oxycarbonitride. An optical microscopy examination demonstrates that the entire surface is coated with a semi-transparent film. The results of XRD analysis allow assuming that in the formation of the surface of the TiNi-based porous material surface a significant role is played by the glassy phase and wollastonite, which imparts special physical-chemical properties and high biocompatibility to the alloy. SEM examination of morphological features of evolution of the mesenchymal cells on the pore surface of the TiNi-based SHS-material within the period 1–28 days shows that on the 7–14-th day the main elements of loose fibrous connective tissue are formed. Dense connective tissue is formed by the 21-st–28-th day