scholarly journals Experimental approaches to creating a tissue-specific matrix for a bioartificial liver

2020 ◽  
Vol 22 (3) ◽  
pp. 123-133
Author(s):  
A. M. Grigoriev ◽  
Yu. B. Basok ◽  
A. D. Kirillova ◽  
L. A. Kirsanova ◽  
N. P. Shmerko ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Metabolic Activity ◽  
Human Liver ◽  
Culture Medium ◽  
Alternative Methods ◽  
Tissue Specific ◽  
The Matrix ◽  
Flow Through ◽  
Liver Fragments ◽  
Static Conditions

Shortage of donor organs for liver transplantation in the treatment of end-stage liver disease dictates the need to develop alternative methods that include technologies on tissue engineering and regenerative medicine. Objective: to study the ability of a tissue-specific matrix from decellularized human liver fragments (DHLF) to maintain adhesion and proliferation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and HepG2 under static conditions and in a flow-through bioreactor. Materials and methods. Treatment with surfactants (SAS) – sodium dodecyl sulfate, Triton X-100 – followed by exposure to DNase was used for decellularization of human liver fragments (no more than 8 mm3). Biochemical screening included the determination of DNA quantity in the test samples. Efficiency of surfactant washing was assessed by the cytotoxicity of the matrix in the NIH 3T3 fibroblast culture. Viability and metabolic activity of cells were assessed via vital staining with a complex of fluorescent dyes LIVE/DEAD ® and PrestoBlue™ (Invitrogen, USA). Morphological examination of the liver cell-engineered constructs was carried out through histological staining and scanning electron microscopy with lanthanide contrast. Results. It was shown that the liver decellularization method used allows to obtain a biocompatible matrix with a residual DNA quantity <1%, which is capable of maintaining adhesion and proliferation of hAT-MSCs and HepG2. On day 7 of cultivation in the bioreactor, there was formation of a single conglomerate of the DHLF matrix with numerous groups of viable cells with a high nuclear-cytoplasmic ratio. The urea content in the culture medium is 1.5 ± 0.1 mmol/L, exceeding that of samples obtained under static conditions. This indicates the metabolic activity of HepG2 in the composition of the obtained culture systems. It was shown that constant flow of the culture medium in the perfusion bioreactor increased the proliferative activity of HepG2 and allowed to provide a more uniform colonization by matrix cells in comparison with static cultivation conditions. Conclusion. The conditions for uniform colonization of DHLFs in a flow-through bioreactor with cell cultures were established. The ability of the matrix to maintain adhesion and proliferation of hADSCs and HepG2 for 11 days indicates that it could be used in liver tissue engineering.

scholarly journals Technology features of decellularization of human liver fragments as tissue-specific fine-grained matrix for cell-engineering liver construction

2018 ◽  
Vol 19 (4) ◽  
pp. 70-77 ◽  
Author(s):  
E. A. Nemets ◽  
L. A. Kirsanova ◽  
Ju. B. Basok ◽  
M. Ju. Schagidulin ◽  
E. A. Volkova ◽  
...  
Keyword(s):  
Structural Properties ◽  
Liver Tissue ◽  
Human Liver ◽  
Sodium Dodecyl ◽  
Donor Liver ◽  
Magnetic Stirrer ◽  
Increased Risk ◽  
Liver Fragments ◽  
Static Conditions ◽  
Decellularized Liver

One of the problems when you create a bioengineered liver, as an alternative to transplantation of the donor liver in the treatment of end-stage liver failure, is the matrix, able to temporarily perform the functions of the natural extracellular matrix (ECM) and provide the necessary conditions to maintain the viability of the liver cells. The main disadvantage of resorbable biopolymer matrices is the absence of tissue specifi c properties and the impossibility of reproducing the unique structure of the ECM of the liver.Aim:to develop technology for decellularization of liver tissue fragments, saving the structural properties of native ECM of the liver.Materials and methods.The decellularization of mechanically grinded human liver fragments was carried out in three changes of buffer solution (pH = 7.4) containing 0.1% sodium dodecyl sulfate and increasing the concentration of Triton X100 (1%, 2% and 3%, respectively). During technology development were investigated the effects of duration, conditions (static, dynamic, rotary system, magnetic stirrer) washing and methods of liver tissue grinding on the completeness of removal of cellular elements and detritus preserving the the liver ECM structure. Slices of decellularized liver tissue samples were stained by hematoxylin and eosin, and Masson method for the detection of connective-tissue elements.Results.Histological analysis methods showed that the best from the point of view of effi ciency of decellularization and the safety of the structure of own human liver ECM, is a mode of washing of liver fragments for three days at room temperature in static conditions, accompanied by stirring by a magnetic stirrer for 2–3 times a day for one hour. Longer time or a large multiplicity of mixing mode is accompanied by increased risk of liver tissue damage. On the basis of the experimental results obtained the algorithm of preliminary study of donor human liver designed to optimize the process of obtaining decellularization fragments of liver tissue was elaborated.Conclusion.It was elaborated the algorithm and technology of obtaining of decellularized liver tissue fragments from the human donor liver which saved the structural properties of native ECM of the liver and complete removal of cellular elements and detritus. 

Effect of supercritical carbon dioxide on the in vivo biocompatible and resorptive properties of tissue-specific scaffolds from decellularized pig liver fragments

2021 ◽  
Vol 11 ◽  
pp. 20-31
Author(s):  
E. A. Nemets ◽  
◽  
A. P. Malkova ◽  
G. A. Dukhina ◽  
A. E. Lazhko ◽  
...  
Keyword(s):  
Medical Devices ◽  
Supercritical Co2 ◽  
Cellular Component ◽  
Pig Liver ◽  
Tissue Specific ◽  
Proliferation And Differentiation ◽  
The Matrix ◽  
Liver Fragments ◽  
Highly Porous

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 detergent residues removing (96 hours of washing in phosphate-salt buffer (PBS) or combined: 24 hours in PBS and 8 hours 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.

On Some Properties of Semi-rings

2018 ◽  
pp. 35-50
Author(s):  
A. I. Belousov
Keyword(s):  
Linear Equations ◽  
Oriented Graph ◽  
Theoretical Computer Science ◽  
Alternative Methods ◽  
Main Role ◽  
Cost Matrix ◽  
Sequential Elimination ◽  
The Matrix ◽  
Systems Of Linear Equations ◽  
The Cost

The main objective of this paper is to prove a theorem according to which a method of successive elimination of unknowns in the solution of systems of linear equations in the semi-rings with iteration gives the really smallest solution of the system. The proof is based on the graph interpretation of the system and establishes a relationship between the method of sequential elimination of unknowns and the method for calculating a cost matrix of a labeled oriented graph using the method of sequential calculation of cost matrices following the paths of increasing ranks. Along with that, and in terms of preparing for the proof of the main theorem, we consider the following important properties of the closed semi-rings and semi-rings with iteration.We prove the properties of an infinite sum (a supremum of the sequence in natural ordering of an idempotent semi-ring). In particular, the proof of the continuity of the addition operation is much simpler than in the known issues, which is the basis for the well-known algorithm for solving a linear equation in a semi-ring with iteration.Next, we prove a theorem on the closeness of semi-rings with iteration with respect to solutions of the systems of linear equations. We also give a detailed proof of the theorem of the cost matrix of an oriented graph labeled above a semi-ring as an iteration of the matrix of arc labels.The concept of an automaton over a semi-ring is introduced, which, unlike the usual labeled oriented graph, has a distinguished "final" vertex with a zero out-degree.All of the foregoing provides a basis for the proof of the main theorem, in which the concept of an automaton over a semi-ring plays the main role.The article's results are scientifically and methodologically valuable. The proposed proof of the main theorem allows us to relate two alternative methods for calculating the cost matrix of a labeled oriented graph, and the proposed proofs of already known statements can be useful in presenting the elements of the theory of semi-rings that plays an important role in mathematical studies of students majoring in software technologies and theoretical computer science.

scholarly journals Fluid Flow Mechanical Stimulation-Assisted Cartridge Device for the Osteogenic Differentiation of Human Mesenchymal Stem Cells

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 927
Author(s):  
Ki-Taek Lim ◽  
Dinesh-K. Patel ◽  
Sayan-Deb Dutta ◽  
Keya Ganguly
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Fluid Flow ◽  
Osteogenic Differentiation ◽  
Flow Condition ◽  
Cultured Cells ◽  
Human Mesenchymal Stem Cells ◽  
Proliferation And Differentiation ◽  
Static Conditions

Human mesenchymal stem cells (hMSCs) have the potential to differentiate into different types of mesodermal tissues. In vitro proliferation and differentiation of hMSCs are necessary for bone regeneration in tissue engineering. The present study aimed to design and develop a fluid flow mechanically-assisted cartridge device to enhance the osteogenic differentiation of hMSCs. We used the fluorescence-activated cell-sorting method to analyze the multipotent properties of hMSCs and found that the cultured cells retained their stemness potential. We also evaluated the cell viabilities of the cultured cells via water-soluble tetrazolium salt 1 (WST-1) assay under different rates of flow (0.035, 0.21, and 0.35 mL/min) and static conditions and found that the cell growth rate was approximately 12% higher in the 0.035 mL/min flow condition than the other conditions. Moreover, the cultured cells were healthy and adhered properly to the culture substrate. Enhanced mineralization and alkaline phosphatase activity were also observed under different perfusion conditions compared to the static conditions, indicating that the applied conditions play important roles in the proliferation and differentiation of hMSCs. Furthermore, we determined the expression levels of osteogenesis-related genes, including the runt-related protein 2 (Runx2), collagen type I (Col1), osteopontin (OPN), and osteocalcin (OCN), under various perfusion vis-à-vis static conditions and found that they were significantly affected by the applied conditions. Furthermore, the fluorescence intensities of OCN and OPN osteogenic gene markers were found to be enhanced in the 0.035 mL/min flow condition compared to the control, indicating that it was a suitable condition for osteogenic differentiation. Taken together, the findings of this study reveal that the developed cartridge device promotes the proliferation and differentiation of hMSCs and can potentially be used in the field of tissue engineering.

scholarly journals Macroporous chitosan/methoxypoly(ethylene glycol) based cryosponges with unique morphology for tissue engineering applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pradeep Kumar ◽  
Viness Pillay ◽  
Yahya E. Choonara
Keyword(s):  
Tissue Engineering ◽  
Polymer Network ◽  
Three Dimensional ◽  
Hysteresis Loops ◽  
Interpenetrating Polymer Network ◽  
Morphological Data ◽  
Porous Scaffolds ◽  
Morphological Variations ◽  
Molecular Stability ◽  
The Matrix

AbstractThree-dimensional porous scaffolds are widely employed in tissue engineering and regenerative medicine for their ability to carry bioactives and cells; and for their platform properties to allow for bridging-the-gap within an injured tissue. This study describes the effect of various methoxypolyethylene glycol (mPEG) derivatives (mPEG (-OCH3 functionality), mPEG-aldehyde (mPEG-CHO) and mPEG-acetic acid (mPEG-COOH)) on the morphology and physical properties of chemically crosslinked, semi-interpenetrating polymer network (IPN), chitosan (CHT)/mPEG blend cryosponges. Physicochemical and molecular characterization revealed that the –CHO and –COOH functional groups in mPEG derivatives interacted with the –NH2 functionality of the chitosan chain. The distinguishing feature of the cryosponges was their unique morphological features such as fringe thread-, pebble-, curved quartz crystal-, crystal flower-; and canyon-like structures. The morphological data was well corroborated by the image processing data and physisorption curves corresponding to Type II isotherm with open hysteresis loops. Functionalization of mPEG had no evident influence on the macro-mechanical properties of the cryosponges but increased the matrix strength as determined by the rheomechanical analyses. The cryosponges were able to deliver bioactives (dexamethasone and curcumin) over 10 days, showed varied matrix degradation profiles, and supported neuronal cells on the matrix surface. In addition, in silico simulations confirmed the compatibility and molecular stability of the CHT/mPEG blend compositions. In conclusion, the study confirmed that significant morphological variations may be induced by minimal functionalization and crosslinking of biomaterials.

scholarly journals Influenza Virus Hemagglutinin and Neuraminidase, but Not the Matrix Protein, Are Required for Assembly and Budding of Plasmid-Derived Virus-Like Particles

2007 ◽  
Vol 81 (13) ◽  
pp. 7111-7123 ◽  
Author(s):  
Benjamin J. Chen ◽  
George P. Leser ◽  
Eiji Morita ◽  
Robert A. Lamb
Keyword(s):  
Influenza Virus ◽  
Culture Medium ◽  
Matrix Protein ◽  
Culture Media ◽  
Protein Composition ◽  
Multivesicular Body ◽  
Viral Proteins ◽  
Dominant Negative ◽  
The Matrix ◽  
Overexpression System

ABSTRACT For influenza virus, we developed an efficient, noncytotoxic, plasmid-based virus-like particle (VLP) system to reflect authentic virus particles. This system was characterized biochemically by analysis of VLP protein composition, morphologically by electron microscopy, and functionally with a VLP infectivity assay. The VLP system was used to address the identity of the minimal set of viral proteins required for budding. Combinations of viral proteins were expressed in cells, and the polypeptide composition of the particles released into the culture media was analyzed. Contrary to previous findings in which matrix (M1) protein was considered to be the driving force of budding because M1 was found to be released copiously into the culture medium when M1 was expressed by using the vaccinia virus T7 RNA polymerase-driven overexpression system, in our noncytotoxic VLP system M1 was not released efficiently into the culture medium. Additionally, hemagglutinin (HA), when treated with exogenous neuraminidase (NA) or coexpressed with viral NA, could be released from cells independently of M1. Incorporation of M1 into VLPs required HA expression, although when M1 was omitted from VLPs, particles with morphologies similar to those of wild-type VLPs or viruses were observed. Furthermore, when HA and NA cytoplasmic tail mutants were included in the VLPs, M1 failed to be efficiently incorporated into VLPs, consistent with a model in which the glycoproteins control virus budding by sorting to lipid raft microdomains and recruiting the internal viral core components. VLP formation also occurred independently of the function of Vps4 in the multivesicular body pathway, as dominant-negative Vps4 proteins failed to inhibit influenza VLP budding.

A Novel Coreflood Test to Evaluate EOR Potential of Wettability-Altering Surfactants in Oil-Wet Heterogeneous Carbonate Reservoirs

2021 ◽  
Author(s):  
Yue Shi ◽  
Kishore Mohanty ◽  
Manmath Panda
Keyword(s):  
Oil Recovery ◽  
Carbonate Reservoirs ◽  
Wettability Alteration ◽  
Low Permeability ◽  
High Permeability ◽  
Matrix Permeability ◽  
Rock Heterogeneity ◽  
The Matrix ◽  
Flow Through ◽  
Main Factors

Abstract Oil-wetness and heterogeneity (i.e., existence of low and high permeability regions) are two main factors that result in low oil recovery by waterflood in carbonate reservoirs. The injected water is likely to flow through high permeability regions and bypass the oil in low permeability matrix. In this study, systematic coreflood tests were carried out in both "homogeneous" cores and "heterogeneous" cores. The heterogeneous coreflood test was proposed to model the heterogeneity of carbonate reservoirs, bypassing in low-permeability matrix during waterfloods, and dynamic imbibition of surfactant into the low-permeability matrix. The results of homogeneous coreflood tests showed that both secondary-waterflood and secondary-surfactant flood can achieve high oil recovery (&gt;50%) from relatively homogenous cores. A shut-in phase after the surfactant injection resulted in an additional oil recovery, which suggests enough time should be allowed while using surfactants for wettability alteration. The core with a higher extent of heterogeneity produced lower oil recovery to waterflood in the coreflood tests. Final oil recovery from the matrix depends on matrix permeability as well as the rock heterogeneity. The results of heterogeneous coreflood tests showed that a slow surfactant injection (dynamic imbibition) can significantly improve the oil recovery if the oil-wet reservoir is not well-swept.

Influence of different concentrations of fibrinogen on the properties of a fibrin matrix for vascular tissue engineering

2021 ◽  
Vol 29 (1) ◽  
pp. 21-34
Author(s):  
Vera G. Matveeva ◽  
Mariam Yu. Khanova ◽  
Tatyana V. Glushkova ◽  
Larisa V. Antonova
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Metabolic Activity ◽  
Vascular Tissue ◽  
Physical And Mechanical Properties ◽  
Vascular Tissue Engineering ◽  
Test Machine ◽  
Fibrin Matrix ◽  
Before And After ◽  
The Difference

Aim. To evaluate the potential utility of fibrin matrices containing 10, 20, and 25 mg/ml of fibrinogen (fibrin-10, fibrin-20, and fibrin-30, respectively) in vascular tissue engineering (VTE). Materials and Methods. Fibrinogen was isolated using the method of ethanol cryoprecipitation and polymerized using a solution of thrombin and CaCl2. The fibrin structure was studied in a scanning electron microscope, and the physical and mechanical properties of the material were tested on a Zwick/Roell test machine. The metabolic activity of endothelial cells (EC) on the fibrin surface was evaluated by the MTT assay, and the viability of fibroblasts in the thickness of fibrin and possibility for migration by in fluorescent and light microscopy. Percent of fibrin shrinkage was determined from the difference in the sample volumes before and after removal of moisture. Results. The fiber diameter did not differ among all fibrin samples, but the pore diameter in fibrin-30 was smaller than those in fibrin-10 and fibrin-20. A possibility for migration of fibroblasts into the depth of the fibrin matrix and preservation of 97-100% viability of cells at a depth 5 mm was confirmed. The metabolic activity of EC on the surface of fibrin-20 and fibrin-30 exceeded that on collagen, fibronectin, and fibrin-10. All fibrin samples shrank in volume to 95.5-99.5%, and the highest shrinkage was seen in fibrin-10. The physical and mechanical properties of fibrin were inferior to those of human A. mammaria by a factor of 10. Conclusion. Fibrin with fibrinogen concentrations of 20 and 30 mg/ml maintains a high metabolic and proliferative activity of EC on the surface and also a high viability of fibroblasts in the matrix. Its availability, ease of preparation, and a number of other favorable properties make fibrin a promising material for VTE. However, the problem of insufficient strength requires further investigations.

Sign in / Sign up

Export Citation Format

Share Document