A. D. Shepelev

Migration and Proliferative Activity of Mesenchymal Stem Cells in 3D Polylactide Scaffolds Depends on Cell Seeding Technique and Collagen Modification

We analyzed viability of mesenchymal stem cells seeded by static and dynamic methods to highly porous fibrous 3D poly-L-lactide scaffolds with similar physical and chemical properties, but different spatial organization modified with collagen. Standard collagen coating promoted protein adsorption on the scaffold surface and improved adhesive properties of 100 μ-thick scaffolds. Modification of 600-μ scaffolds with collagen under pressure increased proliferative activity of mesenchymal stem cells seeded under static and dynamic (delivery of 100,000 cells in 10 ml medium in a perfusion system at a rate of 1 ml/min) conditions by 47 and 648%, respectively (measured after 120-h culturing by MTT test). Dynamic conditions provide more uniform distribution of collagen on scaffold fibers and promote cell penetration into 3D poly-L-lactide scaffolds with thickness >600 μ.

Rheological Features of Fiber Spinning from Polyacrylonitrile Solutions in an Electric Field. Structure and Properties

Spatially ordered fibers of diameter 260-990 nm were produced by electrospinning from polyacrylonitrile (PAN) solutions. The influence of the rheological properties of solutions of PAN and its copolymers was investigated over a broad range of molecular weights during fiber spinning in an electric field. The structural and tensile properties of the fibers were studied.

Proliferative and Differentiation Potential of Multipotent Mesenchymal Stem Cells Cultured on Biocompatible Polymer Scaffolds with Various Physicochemical Characteristics

Biocompatibility of film and fibrous scaffolds from polylactide-based polymers and the relationship between their architecture and the functional characteristics of mesenchymal stem cells were studied. Cell culturing on polylactide-based film and fibrous matrixes did not deteriorate cell morphology and their proliferation and differentiation capacities. The rate of cell proliferation and penetration in microporous 3D matrices with the same porosity parameters and pore size depended on their spatial organization. The above materials can be used as scaffolds for mesenchymal stem cells for creation of tissue engineering implants. The scaffold size and structure should be determined by the defects in the organs in which the regeneration processes have to be stimulated.

Synthesis and Structure of Composite Fibers Based on Silicon and Carbon Obtained by Electrospinning

Composite polymer fibers with a composition of Si-C-O obtained by electrospinning of precursors solution containing polycarbosilane or phenol formaldehyde resins with an admix of organic-silicon compounds were synthesized in order to find efficient new electrode materials for lithium ion batteries. The composition and structure of pyrolized composite fibers were studied by means of X-ray dispersive analysis and X-ray diffraction, Raman spectroscopy, and by AFM and SEM. It was shown that the composite fibers (with a diameter of 0.5–1.5 μm) were nanostructured materials with carbon and silicon-oxy-carbide areas about 2–5 nm in size. A model of the nanostructure of a skeleton for composite fibers synthesized is proposed.

In vitro assessment of electrospun polyamide‐6 scaffolds for esophageal tissue engineering

Artificial tissue-engineered grafts offer a potential alternative to autologous tissue grafts for patients, which can be traumatic. After decellularizing Papio hamadryas esophagus and studying the morphology and physical properties of the extracellular matrix (ECM), we generated electrospun polyamide-6 based scaffolds to mimic it. The scaffolds supported a greater mechanical load than the native ECM and demonstrated similar 3D microstructure, with randomly aligned fibers, 90% porosity, 29 μm maximal pore size, and average fiber diameter of 2.87 ± 0.95 µm. Biocompatibility studies showed that human adipose- and bone marrow-derived mesenchymal stromal cells (AD-MSC and BMD-MSC) adhered to the scaffold surface and showed some proliferation: scaffold cell coverage was 25% after 72 h of incubation when seeded with 1000 cells/mm2 ; cells elongated processes along the polyamide-6, although they flattened 1.67-4 times less than on cell culture plastic. Human umbilical vein endothelial cells, however, showed poor adherence and proliferation. We thus provide in vitro evidence that polyamide-6 scaffolds approximating the esophageal biomechanics and 3D topography of nonhuman primates may provide a biocompatible substrate for both AD-MSC and BMD-MSCs, supporting their adhesion and survival to some degree.

Evaluation properties of bioelectrodes based on carbon superfine materials containing model microorganisms Gluconobacter

We have studied the properties of a bioelectrode formed by the immobilization of Gluconobacter oxydans bacterial cells on carbon superfine materials (CSMs). We use three types of CSMs (as adopted by the working classification CSM 1–3) with different carbonization rates. The bioelectrode is formed by covering the surface of the CSM suspension of bacteria in a chitosan gel. The properties of samples are evaluated by measuring the physiological state of the bacteria immobilized: (a) recording the intensity of cellular respiration, (b) for measuring the charge transport characteristics of electrode (bioelectrocatalysis), and (c) by measuring the electrode impedance. Measurements (b) and (c) are made on two and three-electrode circuits in the oxidation of ethanol in the presence of 2,6-dichlorophenol bacteria electron transport mediator. For CSMs 1 and 2 the electron transport by the oxidation of the substrate is not registered, while for CSM 3 the current generation occurs. The resistance of CSM 3 bioelectrode is below the resistance of CSMs 1 and 2 both before (39.6 kΩ/cm2 for CSM 3, 630 Ω/cm2 for CSM 2, and 1329 Ω/cm2 for CSM 1) and after the addition of the substrate (2.9 kΩ/cm2 for CSM 3, 45 kΩ/cm2 for CSM 2, and 58 kΩ/cm2 for CSM 1). The bioelectrode made of CSM 3 has a capacitance of 196 μF/cm2—greater than two orders of magnitude of the bioelectrode capacity of CSMs 1 and 2 (0.51 and 0.58 μF/cm2, respectively). It is important to further study the properties of the CSM class of materials, which are promising as the basis of mechanically flexible electrodes with controlled parameters.

Nonwoven Materials Produced by Electrospinning for Modern Medical Technologies (Review)

The results from the use of nonwoven materials produced by electrospinning in modern medical technologies are presented. The applications of such materials range from filtration mediums in medical establishments to direct medical articles. Examples of novel dressings are presented. Considerable attention is paid to the use of nonwoven materials in the form of flat multilayered and tubular matrixes in such vigorously developing regions of science as regenerative medicine.

Electrochemical properties and morphology of composite fibers based on silicon and carbon obtained by electroforming

Pyrolized Si/C composite fibers and films were studied in the processes of lithium intercalation-extraction during the operation of rechargeable lithium-ion batteries and supercapacitors. It was found that their electrochemical characteristics differ from those of pure silicon and pure carbon. Analysis of these parameters under charge-discharge conditions allowed us to determine the optimum composition of precursors: FM-1 and TEOS mixtures used as silicon-containing components. The optimum modes and temperatures of fiber pyrolysis were found to have a Si/C ratio of 3/2 in the pyrolyzed fibers and an oxygen content not much greater than 20 at %. The prospects for applying fibers in the form of film electrodes (the best stability in cycling) and adhesives with developed structural networks are shown.

Ozone Resistance of Nonwoven Polypropylene Fibrous Material

The efficiency of ozone absorption by nonwoven polypropylene fibrous material prepared by industrial spunbond technology and changes of its chemical composition and structure after ozone treatment were studied. The effects of ozone treatment at low (250 μg/m3) and high (25 g/m3) ozone concentrations were compared. It was found that oxidative destruction in both instances was localized primarily on the fiber surface. The conditions under which the propylene nonwoven spunbond material was resistant to ozone were determined.

Biocompatibility of Experimental Polymeric Tracheal Matrices

Biocompatibility of a new tracheal matrix is studied. The new matrix is based on polymeric ultra-fiber material colonized by mesenchymal multipotent stromal cells. The experiments demonstrate cytoconductivity of the synthetic matrices and no signs of their degradation within 2 months after their implantation to recipient mice. These data suggest further studies of the synthetic tracheal matrices on large laboratory animals.