A two-layer bioresorbable vascular graft (BVG) with an internal diameter of 2 mm has been developed from biopolymer bioresorbable materials: synthetic polymer polycaprolactone and high-molecular compound of natural origin—gelatin. BVG has a highly porous structure, physical and mechanical characteristics close to a natural blood vessel of a similar diameter, and water permeability of less than 10 mL/(cm2 min). The graft is biocompatible and, when implanted into the infrarenal aorta of a rat, demonstrates blood flow parameters (systolic and diastolic velocity and resistivity index) close to the corresponding parameters of the rat aorta. Under in vivo functioning conditions, the two-layer vascular graft is resistant to stratification and does not provoke an inflammatory reaction, and after 8 weeks of functioning, the formation of neointima is observed on the inner surface of the BVG against the background of the integration of the graft into the body’s surrounding tissues.

A technology fo the formation of porous tubular polymer scaffolds (PTPS) made of polycaprolactone (PCL) with the necessary physical and mechanical characteristics (Young’s modulus 5.5 ± 1.1 MPa, breaking force 10.9 ± 1.6 N and maximum elongation 477 ± 38 %) has been developed. Samples obtained by electrospinning from 2 ml of a 10 % PCL solution in dichloromethane (voltage between electrodes 25 kV, solution delivery rate 4 ml/h, distance to the collector 100 mm, rotation speed of the substrate rod 1000 rpm) showed a minimum surgical permeability of 30.4 ± 1.5 ml/(cm2·min). It is proved that the proposed bioactive coating based on heparin and platelet lysate does not affect the surface structure and physical and mechanical characteristics of the scaffold. It has been shown in vitro that samples of modified PTPS do not exhibit cytotoxicity and hemolytic activity, and improvement of hemocompatible properties occurs due to a decrease in the number and degree of activation of adhered platelets.

Objective: To create 2-mm diameter multilayer porous tubular scaffolds (PTS) with characteristics that resemble small-diameter native blood vessels in terms of characteristics.Materials and methods. PTS made of polycaprolactone (PCL, MM 80000) with a PCL-made sealing coat/layer with gelatin addition (PCL-gelatin) with a diameter of 2 mm were created by electrospinning (NANON-01A). Bioactive coating was applied to the PTS surface by sequential incubation in solutions of bovine serum albumin, heparin (Hp), and platelet lysate (PL). Cytotoxicity was investigated under conditions of direct contact of PTS with a monolayer of NIH/3T3 mouse fibroblasts. Viability of human umbilical vein endothelial cells (EA.hy926) was evaluated using Live/Dead® Viability/Cytotoxicity Kit. Permeability and blood flow parameters of the PTS implanted in the infrarenal section of the rat aorta were recorded using Doppler imaging.Results. A three-layer PTS construct with an inner diameter of 2 mm was developed. Its inner and outer layers were formed from 0.2 mL of PCL solution, and the middle sealing coat/layer was from 0.5 mL of PCL with addition of 30% (by weight of polymer) gelatin. Introduction of the sealing coat/layer reduced surgical porosity (SP) from 56.2 ± 8.7 mL/(cm2·min) for a single-layer PTS made of pure PCL to 8.9 ± 2.6 mL/(cm2·min) for a three-layer PTS. The resulting PTS demonstrated physicomechanical characteristics similar to those of native blood vessels; it also showed no cytotoxicity. Application of a bioactive coating of Hp and PL allowed for increased in vitro adhesion and proliferation of endothelial cells. The technique of implantation of 10 mm long fragments of three-layer PTS into the infrarenal section of a rat aorta was corrected, thus minimizing blood loss and narrowing the anastomosis site. In an acute experiment, it was proven that the prostheses were patent and that blood flow parameters (systolic and diastolic velocity, resistivity index) were close to the corresponding indicators of native rat aorta.Conclusion. The developed three-layer PTS constructs have low SP and physicomechanical properties close to those of native blood vessels. Bioactive coating improves the in vitro matrix properties of PTS relative to human endothelial cells. At short-term implantation into the aorta of experimental animals, PTS showed no early thrombosis, while blood flow parameters were close to those of native rat aorta. Thus, three-layer PTS with bioactive coating can be used as a scaffold for creation of in situ tissue-engineered construct of a small-diameter blood vessel.

Objective : to study the effect of trypsin pretreatment in the porcine articular cartilage decellularization protocol on the ability to restore the biochemical composition and functional properties of the resulting finely dispersed tissue-specific scaffold when co-cultured with human adipose-derived stem cells (hADSCs). Materials and methods . Porcine articular cartilage was micronized to a maximum size of 250 μm. The resulting porcine articular cartilage microparticles (CMps) were treated with trypsin (0.05, 0.25, 0.50%) / EDTA solution at +37 °C for 24 hours. Then, the CMps were successively incubated for 24 hours in three surfactant solutions containing 0.1% sodium dodecyl sulfate and increasing concentration of Triton X-100 (1, 2, 3%) at room temperature and in DNase I solution at +37 °C for 48 hours. The degree of change in the biochemical composition and the ability of decellularized CMps (DCMps) scaffolds within cell-engineered constructs (CECs) to support hADSC adhesion and proliferation, as well as their potential ability to exert a stimulatory regenerative effect, were then assessed. DNA, glycosaminoglycans (GAGs) and collagen content in the DCMps and CECs were examined. The morphology of the samples was examined using histological and immunohistochemistry staining. Results . Histological analysis showed that there were no cells and detritus in the DCMp samples. Pretreatment of CMps samples гыштп a solution with the lowest content of trypsin (0.05%) / EDTA in the samples retained 5.14 ± 0.87 ng/mg DNA in the samples, while GAG content decreased to 5.34 ± 0.9 μg/mg and collagen to 154 ± 34 μg/mg. By day 28 of CEC cultivation, adherent cells had produced their own extracellular matrix (ECM) containing GAGs and collagen. The amount of DNA in it was 6.30 ± 0.11 μg/CEC and that of GAGs was 19.36 ± 0.73 μg/CEC. Conclusion . Pretreatment with trypsin allows achieving uniformly complete decellularized CMps. At the same time, onset of changes in the ECM composition indicates a decrease in the ability of hADSCs to synthesize GAGs and type II collagen during co-culturing with DCMps. The increased proliferative activity of adherent hADSCs, as well as the tissue specificity of the DCMp scaffold will allow further research towards a hydrogel matrix capable of enhancing the specific and stimulating regenerative potential when co-cultured with cells of the same phenotype.

At present, the search for effective ways of restoring peripheral nerves with anatomical damage continues. Autoplasty still remains the gold standard, which, however, is not without its drawbacks. The use of nerve implants for promoting directional axon growth is essential and promising. Objective: to study the biomechanical properties of laboratory samples of an artificial nerve conduit (NGC) made of hybrid biomaterials and to, on cadaveric material, assess the technical feasibility of using them in surgical practice to repair extended peripheral nerve defects. Material and methods . The objects of the study were three electrospun NGC samples: from synthetic material (polycaprolactone, PCL) and hybrid biomaterials (PCL + gelatin or PCL + collagen). The work compared the physical and mechanical properties of NGC: stiffness, plasticity, elasticity, brittleness, resistance to chemical attack, their ability to be impregnated with liquid media, permeability, possibility of making an anastomosis between the implant and the nerve during surgical procedure. Cadaveric material was the object of the study: we used a dissected superficial sensory branch of the human right radial nerve, 2 mm in diameter, isolated on the forearm, about 12 cm in length, because it most corresponded to the diameter of the NGC samples tested. After surgery, the echogenic features of the implants and their anastomoses with the nerve were assessed by ultrasound imaging. Results. It was found that hybrid NGC samples, based on their biomechanical properties, are fundamentally suitable for use in surgical practice, to ensure growth and replacement of a peripheral nerve defect. However, the best composition of a nerve guide can be established after comparative preclinical study of the biocompatible and functional properties of hybrid material samples. Conclusion. The physical and mechanical properties of the investigated NGC samples made of hybrid biomaterials meet the technical requirements for implantable nerve conduits for surgical application.

High surgical porosity (SP) is one of the causes of significant blood loss, as well as hematoma formation. So, reducing the SP of small-diameter vascular grafts (VGs) is a crucial task. The objective of this work was to develop a technology for the formation of polycaprolactone (PCL)-based small-diameter VGs with a bioactive coating with reduced SP. Materials and methods . Porous VGs with an inner diameter of 3 mm were fabricated by electrospinning from 5% PCL solution with addition of 5–30% gelatin (PCL/G) on an NANON-01A unit (MECC CO, Japan). Bioactive coating was applied by sequential incubation of VGs in solutions of bovine serum albumin, heparin and platelet lysate with fixation in a glutaric aldehyde solution. The surface structure and mechanical properties of the samples were investigated. Functional properties of the bioactive VGs were evaluated in relation to their interaction with cell cultures in vitro. Results . It was found that introduction of gelatin into the working solution reduces SP from 30.4 ± 1.5 mL/(cm2 ·min) to 2.8 ± 0.5 ml/(cm2 ·min). It was shown that at a PCL/gelatin ratio of 9 : 1, the outer and inner sides of the bioactive VGs samples are characterized by surface uniformity (no defects), mechanical properties close to blood vessels of the same diameter (Young’s modulus 6.7 ± 2.1 MPa, tensile strength 26.7 ± 4.9 N and elongation to break 423 ± 80%) and ability to support adhesion and proliferation of human umbilical vein endothelial cell line, EA.hy926. Conclusion . Introduction of 10% gelatin content (by the polymer weight) into PCL solution reduces the SP of small-diameter VGs, leads to uniformity in their inner and outer surface, improvement in their mechanical properties without reducing their ability to support adhesion and proliferation of vascular endothelial cells.

A significant lack of donor organs restricts the opportunity to obtain tissue-specific scaffolds for tissue-engineering technologies. One of the acceptable solutions is the development of decellularization protocols for a human donor pancreas unsuitable for transplantation. A protocol of obtaining a biocompatible tissue-specific scaffold from decellularized fragments with pronounced human pancreas lipomatosis signs with preserved basic fibrillary proteins of a pancreatic tissue extracellular matrix was developed. The scaffold supports the adhesion and proliferation of human adipose derived stem cell (hADSCs) and prolongs the viability and insulin-producing function of pancreatic islets. Experiments conducted allow for the reliance on the prospects of using the donor pancreas unsuitable for transplantation in the technologies of tissue engineering and regenerative medicine, including the development of a tissue equivalent of a pancreas.

Structural and morphological changes in the film samples of poly(oxybutyrate-co-oxyvalerate) (P(OB-OV)) and poly-ε-caprolactone (PCL) during accelerated oxidative degradation in the Fenton reagent are studied by IR spectroscopy, DSC, and scanning electron microscopy. It is shown that phase separation of the P(OB-OV) and PCL components is observed in the initial mixture. The melting of different phases of P(OB-OV) is observed at 147 and 157°C, and PCL melts at 61°C. The degrees of crystallinity of P(OB-OV) and PCL in the mixture are 67 and 50%, respectively. It is found that the degradation of P(OB-OV) predominates during the incubation of the samples of the composite in the Fenton solution for 2 to 12 weeks. It is possible to substantially change the rate of oxidative degradation and the molecular weight and degree of crystallinity of a P(OB-OV):PCL polymer composite material by varying the ratio of the components.

In contrast to decellularization of soft tissues for use as tissue-specific matrices in the creation of tissue-engineered constructs, decellularization of cartilage tissue requires several processing techniques, which can negatively affect the biocompatibility and functional properties of the native extracellular matrix (ECM).Objective: to study the biocompatible and functional properties of microdispersed tissue-specific 3D matrix from a porcine cartilage that is decellularized by sequential use of chemical, physical and enzymatic techniques.Materials and methods. For decellularization, microdispersed cartilage particles (MCPs), obtained by cryomilling, were incubated in detergent solutions (sodium dodecyl sulfate and Triton X-100), then treated with supercritical carbon dioxide (scCO2) with 10% ethanol and DNase I. The Ames test (Salmonella typhimurium reverse mutation assay) was used to determine the genotoxicity of decellularized microdispersed cartilage particles (dMCPs). Local and general toxic effects, as well as resorption of dMCPs were studied in vivo on sexually mature outbred rats. Decellularized MCP specimens (10 mg) were implanted into the thigh muscle tissue. Viability of human adipose-derived mesenchymal stem/stromal cells (hAdMSCs), when cultured on dMCPs, was analyzed by in vivo microscopy, stained with fluorescent Calcein AM dye. Cell metabolic activity was assessed using PrestoBlue™ Cell Viability Reagent.Results. It has been proven that porcine dMCPs implanted in rat muscle after treatment with scCO2 do not exhibit local and general toxic effects, and do not show genotoxicity and negative effects on the reproductive system of animals. After 6 months of in vivo experiment, most (87%) of the implanted decellularized cartilage was resorbed. It was shown that the resulting matrices are able to support adhesion and proliferation of hAdMSCs. Conclusion. Porcine dMCP specimens are suitable for biocompatible medical products in terms of local and general toxic effects, genotoxicity and reproductive toxicity, and can be used as a matrix for creating cell- and tissue-engineered cartilage constructs.

One of the approaches to restoring the structure of damaged cartilage tissue is an intra-articular injection of tissue-engineered medical products (TEMPs) consisting of biocompatible matrices loaded with cells. The most interesting are the absorbable matrices from decellularized tissues, provided that the cellular material is completely removed from them with the maximum possible preservation of the structure and composition of the natural extracellular matrix. The present study investigated the mechanical, biochemical, and biological properties of decellularized porcine cartilage microparticles (DCMps) obtained by techniques, differing only in physical treatments, such as freeze-thaw cycling (Protocol 1), supercritical carbon dioxide fluid (Protocol 2) and ultrasound (Protocol 3). Full tissue decellularization was achieved, as confirmed by the histological analysis and DNA quantification, though all the resultant DCMps had reduced glycosaminoglycans (GAGs) and collagen. The elastic modulus of all DCMp samples was also significantly reduced. Most notably, DCMps prepared with Protocol 3 significantly outperformed other samples in viability and the chondroinduction of the human adipose-derived stem cells (hADSCs), with a higher GAG production per DNA content. A positive ECM staining for type II collagen was also detected only in cartilage-like structures based on ultrasound-treated DCMps. The biocompatibility of a xenogenic DCMps obtained with Protocol 3 has been confirmed for a 6-month implantation in the thigh muscle tissue of mature rats (n = 18). Overall, the results showed that the porcine cartilage microparticles decellularized by a combination of detergents, ultrasound and DNase could be a promising source of scaffolds for TEMPs for cartilage reconstruction.

Introduction. Developing a tissue-engineered pancreatic construct (TEPC) involves a search for matrices/scaffolds capable of mimicking the structure and composition of the natural extracellular matrix (ECM), which is an important component of the tissue microenvironment. A cell-free, tissue-specific matrix obtained from pancreas decellularization seems to be the most suitable for creation of a TEPC. The choice of pancreatic tissue decellularization protocol should take into account the morphological characteristics of the original pancreas. Preservation of the architectonics and composition of the native tissue in the decellularized pancreas matrix (DPM), and the presence of native ECM components allow for creation of conditions for prolonged vital activity of functionally active islet (insulin-producing) cells when creating TEPC. Objective : to determine the optimal parameters for decellularization of deceased donor pancreas with fibrosis, lipomatosis, and without pronounced signs of fibrosis and lipomatosis. Materials and methods . We used the caudal part of the pancreas obtained after multiorgan procurement from deceased donors, which was unsuitable for transplantation. Tissue-specific matrix was obtained by a combination of physical and chemical methods of pancreatic decellularization. A freeze-thaw cycle protocol and two protocols using osmotic shock were used. Samples of initial pancreatic tissue and decellularized fragments were subjected to histological analysis. Result s. It was shown that a physico-chemical method with freeze-thaw cycles is suitable for effective pancreatic decellularization in severe lipomatosis; a physico-chemical method using osmotic shock, but different protocol variants, is suitable for pancreas with diffuse fibrosis and for pancreas without pronounced signs of fibrosis and lipomatosis. Conclusion . For complete human pancreatic decellularization, the protocol should be correlated with histological features of the original tissue.

The creation of bioengineered tissue/organ equivalents is closely related to the development of biodegradable, highly porous 3D scaffolds, which to some extent provide the microenvironment necessary to maintain the viability of the cellular component. According to many researchers, the most interesting are tissue-specific matrices that can selectively support the adhesion, proliferation, and differentiation of tissue cells of those organs from which they are obtained by decellularization. It was shown that, during intramuscular implantation in rats of decellularized pig liver fragments (DLFp), independent of the method of removal of detergent residues (96 h of washing in phosphate-buffered saline (PBS) or combined: 24 h in PBS and 8 h with supercritical CO2 (sc-CO2)), the samples meet the requirements for medical devices in terms of local and general toxic effects. Thus, the use of sc-CO2 made it possible to reduce the duration of the technology for producing biocompatible tissue-specific matrices based on DLFp by 3 times. Moreover, when using sc-CO2 at the stage of washing the DLFp matrix, a “mild reaction” of the tissue to the sample is observed during 2 months of intramuscular implantation of the matrix in rats with its complete resorption after 3 months of the experiment. Under the same conditions, the duration of a similar local action of DLFp washed in the PBS on the tissue is 3 months with degradation of 63% of the matrix of the sample size.

In terms of method of production, collagen carriers are subdivided into materials obtained on the basis of extracellular matrix (ECM) components, particularly collagen-containing hydrogels and decellularized tissue. Objective : to compare in vitro the ability of biopolymer microheterogeneous collagen-containing hydrogel (BMCH) and tissue-specific matrix from decellularized porcine articular cartilage (DPAC) to support adhesion, proliferation and chondrogenic differentiation of human adipose-derived mesenchymal stem cells (hAMSCs). Materials and methods . For cartilage decellularization, we carried out treatment with surfactants (sodium dodecyl sulfate, Triton X-100) followed by exposure in DNAase. The metabolic activity of hAMSCs was assessed by PrestoBlue™ (Invitrogen, USA) staining. The morphological study of cell-engineered constructs (CECs) formed by culturing hAMSCs in the presence of matrices was performed using histological staining and scanning electron microscopy (SEM) with lanthanide contrasting. Results . The number of cells on the surface of both BMCH and DPAC increased within 14 days. Mitochondrial activity of the cells was 1.7, 1.7, and 1.3 times higher on days 3, 10, and 14 when cultured on DPAC compared to BMCH, respectively. On day 14 of cultivation in the chondrogenic culture medium, hAMSCs formed cell layers on the DPAC surface and on the BMCH surface. Cytoplasm of the cells included numerous granules, which, when stained, resembled the matrix itself. On the DPAC matrix surface, cells were more evenly distributed, whereas in the case of BMCH, cell adhesion and proliferation were observed only in certain areas. The ECM produced by the cells contained collagen and glycosaminoglycans (GAGs). Conclusion . The ability of DPAC obtained according to the developed protocol to form CECs with hAMSCs with uniform distribution of cells and their production of specific collagen- and GAG-containing ECM suggests that DPAC is effective in regeneration of damaged cartilage. Chondrogenic differentiation of hAMSCs was observed both when cultured with BMCH and with DPAC. When creating a tissue equivalent of cartilage in vitro, the advantage of using tissue-specific matrix over BMCH should be considered.

The creation of a tissue-engineered structure of the pancreas based on isolated pancreatic islets is hindered by problems associated with maintaining their viability and insulin-producing function. Both biopolymer and tissue-specific scaffolds can contribute to the preservation of the structure and function of pancreatic islets in vitro and in vivo . Comparative morphofunctional analysis in vitro of two different types of tissue-engineered structures of the pancreas, which represent culture systems of isolated islets with biomimetics of an extracellular matrix - a biopolymer collagen-containing scaffold and a tissue-specific scaffold obtained as a result of pancreatic decellularization, - was performed. The results showed that the use of scaffolds in the creation of a tissue-engineered design of the pancreas contributes not only to the preservation of the viability of the islets, but also to the prolongation of their insulin-producing functions, compared to the monoculture of the islets in vitro . A significant increase was found in the basal and stimulated (under glucose load) insulin concentrations in the tissue of engineered structures studied, at the same time the advantage of using a tissue-specific scaffold compared to a biopolymer collagen-containing scaffold was shown. We think that these studies will become a platform for creating a tissue-engineered design of the human pancreas for treatment of type 1 diabetes mellitus.

Objective: to investigate the efficacy of supercritical carbon dioxide (sc-CO2) for enhancштп the biocompatibility of biopolymer scaffolds from biodegradable materials and tissue-specific scaffolds from decellularized porcine liver slices (PLSs) or fine porcine cartilage particles (FPCPs).Materials and methods. Biopolymer scaffolds of a polyoxy(butyrate-co-valerate) and gelatin copolymer composition, 4 mm in diameter and 80 mm in length, were formed by electrospinning (NANON-01A, MECC CO, Japan) and stabilized by incubation in glutaraldehyde vapor for 48 hours at room temperature. For decellularization, PLSs and FPCPs were incubated under periodic stirring in buffer (pH = 7.4) solutions of sodium dodecyl sulfate (0.1%) and Triton X-100 with increasing concentrations (1, 2, and 3%). Treatment in a sc-CO2 atmosphere was done at 150–300 bar pressure, 35 °C temperature, and 0.25–2.5 mL/min flow rate of sc-CO2 for 8–24 hours. 10% ethanol was introduced as a polarity modifier. Cytotoxicity was studied according to GOST ISO 10993-5-2011. The growth of NIH/3T3 in the presence of samples was studied using an interactive optical system IncuCyte Zoom.Results. The effect of the sc-CO2 flow rate and pressure, and the effect of addition of ethanol, on the biocompatibility of scaffolds was investigated. It was found that treatment at a low sc-CO2 flow rate (0.25 mL/min) does not achieve the required cytotoxicity. Complete absence of cytotoxicity in biopolymer scaffolds was achieved in the presence of 10% ethanol, at a sc-CO2 flow rate of 2.5 mL/min, 300 bar pressure and 35 °C temperature after 8 hours of treatment. Effective removal of cytotoxic detergents from decellularized liver occurs already at a 150-bar pressure and does not require the addition of ethanol. Adding ethanol to sc-CO2 eliminates not only the cytotoxic, but also the cytostatic effect of tissue-specific scaffolds.Conclusion. Sc-CO2 treatment is an effective way to enhance the biocompatibility of three-dimensional porous matrices produced using cytotoxic substances: bifunctional crosslinking agents for biopolymer scaffolds and surfactants in the case of tissue-specific matrices. Addition of ethanol as a polarity modifier improves the treatment efficiency by eliminating both cytotoxic and cytostatic effects.

The main problem with decellularization of liver tissue as a tissue-specific matrix/scaffold in liver bioengineered structures is the need to maximize the preservation of the original three-dimensional structure of the tissue and the main components of its extracellular matrix (ECM) while removing cells and genetic material. The attempts to use the existing protocols for the decellularization of other tissues and organs have been unsuccessful. The aim of the work is to develop a method for creation of a tissue-specific microdispersed matrix from decellularized porcine liver (TMM DLp). The protocol for decellularization of porcine liver (Lp) fragments has been developed on the basis of the complex application of chemical (sodium dodecyl sulfate and Triton X100), biochemical (DNase I), and physical (supercritical CO2) methods for treatment of the initial tissue. As a result of the found optimal conditions for decellularization of Lp with subsequent cryomicronization of decellularized DLp, an injectable form of the microdispersed tissue-specific matrix was obtained, which represents decellularized porcine liver microparticles with the size of 100–200 μm with the residual amount of DNA no more than 10 ± 1.5 ng/mg (less than 1.0%), with the preservation of the microstructure and basic composition of the liver ECM. According to the in vitro assessment, biocompatible properties of tissue-specific matrix samples meet the criteria of biological safety for cytotoxicity and hemolytic activity.

Objective: to develop a method for modifying composite small-diameter porous tubular biopolymer scaffolds based on bacterial copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and gelatin modified with a double-layered bioactive coating based on heparin (Hp) and platelet lysate (PL) that promote adhesion and proliferation of cell cultures.Materials and methods. Composite porous tubular biopolymer scaffolds with 4 mm internal diameter were made by electrospinning from a 1 : 2 (by volume) mixture of a 10% solution of poly(3-hydroxybutyrateco- 3-hydroxyvalerate) copolymer, commonly known as PHBV, and a 10% solution of gelatin, respectively, in hexafluoro-2-propanol. The structure of the scaffolds was stabilized with glutaraldehyde vapor. The scaffolds were modified with a bioactive Hp + PL-based coating. The surface morphology of the samples was analyzed using scanning electron microscopy. Biological safety of the modified scaffolds in vitro (hemolysis, cytotoxicity) was evaluated based on the GOST ISO 10993 standard. Interaction with cultures of human endothelial cell line (EA. hy926) and human adipose-derived mesenchymal stem cells (hADMSCs) was studied using vital dyes.Results. We developed a method for modifying small-diameter composite porous tubular biopolymer scaffolds obtained by electrospinning from a mixture of PHBV and gelatin modified with double-layered bioactive coating based on covalently immobilized Hp and human PL. The modified scaffold was shown to have no cytotoxicity and hemolytic activity in vitro. It was also demonstrated that the developed coating promotes hADMSC adhesion and proliferation on the external surface and EA.hy926 on the internal surface of the composite porous tubular biopolymer scaffolds in vitro.Conclusion. The developed coating can be used for the formation of in vivo tissueengineered small-diameter vascular grafts.

Mesenchymal stromal cells (MSCs) have shown a high potential for cartilage repair. Collagen-based scaffolds are used to deliver and retain cells at the site of cartilage damage. The aim of the work was a comparative analysis of the capacity of the MSCs from human adipose tissue to differentiate into chondrocytes in vitro and to stimulate the regeneration of articular cartilage in an experimental model of rabbit knee osteoarthrosis when cultured on microheterogenic collagen-based hydrogel (MCH) and the microparticles of decellularized porcine articular cartilage (DPC). The morphology of samples was evaluated using scanning electron microscopy and histological staining methods. On the surface of the DPC, the cells were distributed more uniformly than on the MCH surface. On day 28, the cells cultured on the DPC produced glycosaminoglycans more intensely compared to the MCH with the synthesis of collagen type II. However, in the experimental model of osteoarthrosis, the stimulation of the cartilage regeneration was more effective when the MSCs were administered to the MCH carrier. The present study demonstrates the way to regulate the action of the MSCs in the area of cartilage regeneration: the MCH is more conducive to stimulating cartilage repair by the MSCs, while the DPC is an inducer for a formation of a cartilage-like tissue by the MSCs in vitro.

A method for obtaining a microdispersed tissue-specific matrix from decellularized porcine articular cartilage while maintaining morphological and functional properties of the extracellular matrix with no signs of cytotoxicity was developed. The cartilage particle size distribution in suspension after cryogenic grinding was determined using laser diffraction analysis. The range of sizes of the obtained cartilage microparticles suggests the possibility of their administration by injection (<220 μm). The combination of stages, including three freeze/thaw cycles (–196/37°C) followed by treatment with solutions of surface-active substances (surfactants), sodium dodecyl sulfate and Triton X-100, and DNase resulted in the complete removal of non-decellularized microparticles. The residual DNA content was 9.11 ± 1.13 ng/mg of tissue. The effectiveness of surfactant washing was assessed by the cytotoxicity of the matrix on the culture of human adipose derived mesenchymal stromal cells (hADSCs). To assess the hemocompatibility of the obtained samples, their hemolytic activity was studied in vitro. The adhesion and proliferation of hADSCs on the matrix surface were studied on day 21 of cultivation. The matrix did not exhibit hemolytic activity and cytotoxicity with respect to hADSCs. hADSCs in the samples were actively proliferating on the matrix surface. The biocompatibility and hemocompatibility of the obtained matrix in vitro indicate its potential for application in cartilage regenerative medicine.

The spin-probe method is applied to estimate the rate and degree of sorption of water vapor by gelatin-based polymers. The rate and the sorption degree of gelatins are shown to be affected by the extent that they are crosslinked. Cross-linked gelatin swells in water vapor at 300 K for a time period that is thrice as long as the time for which native gelatin swells in the same conditions.