21 results on '"Stankevich KS"'
Search Results
2. Evolution of the Radio Emission from Young SNRs according to Observational Data
- Author
-
Stankevich, KS, primary
- Published
- 1979
- Full Text
- View/download PDF
3. Comparison of the Influence of 'Solvent/Non-Solvent' Treatment for the Attachment of Signal Molecules on the Structure of Electrospun PCL and PLLA Biodegradable Scaffolds
- Author
-
Goreninskii Semen, Stankevich Ksenia, Bolbasov Evgeny, Danilenko Nadezhda, Filimonov Victor, and Tverdokhlebov Sergei
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Electrospun biodegradable scaffolds (matrixes) made of poly(ε-caprolactone) (PCL) and poly(L-lactic acid) (PLLA) are three-dimensional fibrous structures that are commonly used in regenerative medicine and drug delivery systems. Modification of such structures allows manipulating with biological and immune response. Previously, our team suggested a number of surface modification strategies for thin films made of PLLA. One of the proposed strategies are based on treatment of the material with “solvent/non-solvent” mixture that allows absorbing biologically active molecules or linkers on the surface of the sample. The aim of this work was to compare the influence of “solvent/non-solvent” treatment on the structure and crystallinity of the elecrospun biodegradable PCL and PLLA scaffolds. For that purpose, original PCL and PLLA scaffolds were treated with mixture of toluene and ethanol in different proportions. Morphology of the obtained samples was studied using scanning electron microscopy. It was shown that “solvent/non-solvent” treatment doesn’t lead to changes in scaffolds morphology such as gluing or cutting of the matrix fibers. By means of X-ray diffraction analysis it was shown that treatment of the samples with selected mixtures doesn’t change material crystallinity. Thus, it was demonstrated that proposed composition of the “solvent/nonsolvent” mixture can be used for the modification of electrospun PCL and PLLA scaffolds.
- Published
- 2016
- Full Text
- View/download PDF
4. Catalytic dinitrogen reduction to hydrazine and ammonia using Cr(N 2 ) 2 (diphosphine) 2 complexes.
- Author
-
Beasley CH, Duletski OL, Stankevich KS, Arulsamy N, and Mock MT
- Abstract
The synthesis, characterization of trans -[Cr(N
2 )2 (depe)2 ] (1) is described. 1 and trans -[Cr(N2 )2 (dmpe)2 ] (2) catalyze the reduction of N2 to N2 H4 and NH3 in THF using SmI2 and H2 O or ethylene glycol as proton sources. 2 produces the highest total fixed N for a molecular Cr catalyst to date.- Published
- 2024
- Full Text
- View/download PDF
5. Low-cost, versatile, and highly reproducible microfabrication pipeline to generate 3D-printed customised cell culture devices with complex designs.
- Author
-
Hagemann C, Bailey MCD, Carraro E, Stankevich KS, Lionello VM, Khokhar N, Suklai P, Moreno-Gonzalez C, O'Toole K, Konstantinou G, Dix CL, Joshi S, Giagnorio E, Bergholt MS, Spicer CD, Imbert A, Tedesco FS, and Serio A
- Subjects
- Microfluidics methods, Printing, Three-Dimensional, Lab-On-A-Chip Devices, Microtechnology, Cell Culture Techniques
- Abstract
Cell culture devices, such as microwells and microfluidic chips, are designed to increase the complexity of cell-based models while retaining control over culture conditions and have become indispensable platforms for biological systems modelling. From microtopography, microwells, plating devices, and microfluidic systems to larger constructs such as live imaging chamber slides, a wide variety of culture devices with different geometries have become indispensable in biology laboratories. However, while their application in biological projects is increasing exponentially, due to a combination of the techniques, equipment and tools required for their manufacture, and the expertise necessary, biological and biomedical labs tend more often to rely on already made devices. Indeed, commercially developed devices are available for a variety of applications but are often costly and, importantly, lack the potential for customisation by each individual lab. The last point is quite crucial, as often experiments in wet labs are adapted to whichever design is already available rather than designing and fabricating custom systems that perfectly fit the biological question. This combination of factors still restricts widespread application of microfabricated custom devices in most biological wet labs. Capitalising on recent advances in bioengineering and microfabrication aimed at solving these issues, and taking advantage of low-cost, high-resolution desktop resin 3D printers combined with PDMS soft lithography, we have developed an optimised a low-cost and highly reproducible microfabrication pipeline. This is thought specifically for biomedical and biological wet labs with not prior experience in the field, which will enable them to generate a wide variety of customisable devices for cell culture and tissue engineering in an easy, fast reproducible way for a fraction of the cost of conventional microfabrication or commercial alternatives. This protocol is designed specifically to be a resource for biological labs with limited expertise in those techniques and enables the manufacture of complex devices across the μm to cm scale. We provide a ready-to-go pipeline for the efficient treatment of resin-based 3D-printed constructs for PDMS curing, using a combination of polymerisation steps, washes, and surface treatments. Together with the extensive characterisation of the fabrication pipeline, we show the utilisation of this system to a variety of applications and use cases relevant to biological experiments, ranging from micro topographies for cell alignments to complex multipart hydrogel culturing systems. This methodology can be easily adopted by any wet lab, irrespective of prior expertise or resource availability and will enable the wide adoption of tailored microfabricated devices across many fields of biology., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Hagemann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2024
- Full Text
- View/download PDF
6. Hydrogel Cross-Linking via Thiol-Reactive Pyridazinediones.
- Author
-
Bahou C, Spears RJ, Ramírez Rosales AM, Rochet LNC, Barber LJ, Stankevich KS, Miranda JF, Butcher TC, Kerrigan AM, Lazarov VK, Grey W, Chudasama V, and Spicer CD
- Subjects
- Humans, Cross-Linking Reagents chemistry, Hydrogels chemistry, Sulfhydryl Compounds chemistry
- Abstract
Thiol-reactive Michael acceptors are commonly used for the formation of chemically cross-linked hydrogels. In this paper, we address the drawbacks of many Michael acceptors by introducing pyridazinediones as new cross-linking agents. Through the use of pyridazinediones and their mono- or dibrominated analogues, we show that the mechanical strength, swelling ratio, and rate of gelation can all be controlled in a pH-sensitive manner. Moreover, we demonstrate that the degradation of pyridazinedione-gels can be induced by the addition of thiols, thus providing a route to responsive or dynamic gels, and that monobromo-pyridazinedione gels are able to support the proliferation of human cells. We anticipate that our results will provide a valuable and complementary addition to the existing toolkit of cross-linking agents, allowing researchers to tune and rationally design the properties of biomedical hydrogels.
- Published
- 2023
- Full Text
- View/download PDF
7. Highly diastereo- and branched-selective rearrangement of substituted N -alloc- N -allyl ynamides.
- Author
-
Jackson OD, Stankevich KS, and Cook MJ
- Subjects
- Ligands, Catalysis, Nitriles, Carbon
- Abstract
An auto-tandem catalytic, branched-selective rearrangement of substituted N -alloc- N -allyl ynamides was developed. This reaction provides ready access to complex quaternary nitrile products with vinylogous stereocentres in excellent diastereoselectivity, including contiguous all-carbon quaternary centres. The stereochemical outcome is determined via a Pd(0) catalysed dipolar ketenimine aza-Claisen rearrangement and computational studies exemplify the key role ligand geometry plays.
- Published
- 2022
- Full Text
- View/download PDF
8. A Highly Stereospecific Claisen-Sakurai Approach to Densely Functionalized Cyclopentenols.
- Author
-
Stankevich KS and Cook MJ
- Subjects
- Cyclization, Stereoisomerism
- Abstract
The formation of highly substituted cyclopentenols was developed using a Claisen-Sakurai reaction. Both elements of the reaction can be performed in a one-pot sequence that provides the corresponding cyclized products in high stereoselectivity. The stereochemical outcome is defined by a combination of Claisen stereospecificity and stereoelectronic effects in the Sakurai cyclization that promotes reactivity via an anti -S
E ' antiperiplanar transition state. This was determined by examination of the product stereochemistry and through detailed DFT analysis.- Published
- 2022
- Full Text
- View/download PDF
9. Design, synthesis and biological evaluation of novel O-substituted tryptanthrin oxime derivatives as c-Jun N -terminal kinase inhibitors.
- Author
-
Schepetkin IA, Kovrizhina AR, Stankevich KS, Khlebnikov AI, Kirpotina LN, Quinn MT, and Cook MJ
- Abstract
The c-Jun N -terminal kinase (JNK) family includes three proteins (JNK1-3) that regulate many physiological processes, including inflammatory responses, morphogenesis, cell proliferation, differentiation, survival, and cell death. Therefore, JNK represents an attractive target for therapeutic intervention. Herein, a panel of novel tryptanthrin oxime analogs were synthesized and evaluated for JNK1-3 binding (K
d ) and inhibition of cellular inflammatory responses (IC50 ). Several compounds exhibited submicromolar JNK binding affinity, with the most potent inhibitor being 6-(acetoxyimino)indolo[2,1- b ]quinazolin-12(6 H )-one ( 1j ), which demonstrated high JNK1-3 binding affinity (Kd = 340, 490, and 180 nM for JNK1, JNK2, and JNK3, respectively) and inhibited lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) transcription activity in THP-1Blue cells and interleukin-6 (IL-6) production in MonoMac-6 monocytic cells (IC50 = 0.8 and 1.7 μM, respectively). Compound 1j also inhibited LPS-induced production of several other proinflammatory cytokines, including IL-1α, IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF) in MonoMac-6 cells. Likewise, 1j inhibited LPS-induced c-Jun phosphorylation in MonoMac-6 cells, directly confirming JNK inhibition. Molecular modeling suggested modes of binding interaction of selected compounds in the JNK3 catalytic site that were in agreement with the experimental JNK3 binding data. Our results demonstrate the potential for developing anti-inflammatory drugs based on these nitrogen-containing heterocyclic systems., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Schepetkin, Kovrizhina, Stankevich, Khlebnikov, Kirpotina, Quinn and Cook.)- Published
- 2022
- Full Text
- View/download PDF
10. Intramolecular amination via acid-catalyzed rearrangement of azides: a potent alternative to intermolecular direct electrophilic route.
- Author
-
Stankevich KS, Lavrinenko AK, and Filimonov VD
- Subjects
- Amination, Amines chemistry, Catalysis, Nitrogen chemistry, Protons, Quantum Theory, Stilbenes chemistry, Amines chemical synthesis, Azides chemistry, Diazonium Compounds chemistry
- Abstract
Although acid-catalyzed intramolecular rearrangement of organic azides is an attractive route to amines, its mechanism and synthetic prospective are still debated. Herein, through computational and experimental studies, we demonstrated that azide intramolecular rearrangement could serve as a potent synthetic route to a sought-after amine functionality including preparation of difficult to access and valuable heterocyclic amines. Using quantum chemical calculations at MP2/aug-cc-pVTZ and B3LYP/aug-cc-pVDZ levels, we discovered that this reaction proceeds via a concerted transition state with nitrogen elimination and alkyl/aryl migration occurring at the same time. Two conformers of protonated azides - syn- and anti- - were shown to precede corresponding transition states. It was shown that the reaction follows Curtin-Hammett scenario as the energy gap required for conformer interconversion was substantially lower than activation barrier of either transition state. Intramolecular amination via azide rearrangement was predicted to be a selective process with migratory aptitude increasing in a row alkyl
- Published
- 2021
- Full Text
- View/download PDF
11. Solution blow spinning of PLLA/hydroxyapatite composite scaffolds for bone tissue engineering.
- Author
-
Popkov AV, Kulbakin DE, Popkov DA, Gorbach EN, Kononovich NA, Danilenko NV, Stankevich KS, Choynzonov EL, Zheravin АА, Khlusov IA, Bondar LN, Perelmuter VM, Bolbasov EN, and Tverdokhlebov SI
- Subjects
- Animals, Biotechnology methods, Bone Substitutes chemistry, Bone Substitutes pharmacology, Bone and Bones drug effects, Male, Rats, Rats, Wistar, Durapatite chemistry, Durapatite pharmacology, Osteogenesis drug effects, Polyesters chemistry, Polyesters pharmacology, Tissue Engineering methods, Tissue Scaffolds chemistry
- Abstract
Composite poly-L-lactide acid-based scaffolds with hydroxyapatite (HAp) content up to 75 wt.% were fabricated via solution blow spinning. The influence of HAp concentration on structure, wettability, mechanical properties and chemical and phase composition of the produced materials was examined. It was found that with an increase of HAp content the average fiber diameter was increased, the uniaxial strength and relative elongation were reduced, while the phase composition and surface wettability did not change. The performance of the scaffolds during implantation in the parietal bone of a rat skull for a period from 15 to 90 days was studied. The materials have shown high ability to integrate with both soft and hard tissues. It was found that scaffolds with 25 wt.% HAp content significantly enhance osteogenesis during scarification (damage) of the periosteum. Overall, the fabricated scaffolds proved to be highly efficient for replacing bone defects in long tubular bones., (© 2021 IOP Publishing Ltd.)
- Published
- 2021
- Full Text
- View/download PDF
12. Pd-Catalyzed Rearrangement of N -Alloc- N -allyl Ynamides via Auto-Tandem Catalysis: Evidence for Reversible C-N Activation and Pd(0)-Accelerated Ketenimine Aza-Claisen Rearrangement.
- Author
-
Alexander JR, Shchepetkina VI, Stankevich KS, Benedict RJ, Bernhard SP, Dreiling RJ, and Cook MJ
- Abstract
An auto-tandem catalytic double allylic rearrangement of N -alloc- N -allyl ynamides was developed. This reaction proceeds through two separate and distinct catalytic cycles with both decarboxylative Pd-π-allyl and Pd(0)-promoted aza-Claisen rearrangements occurring. A detailed mechanistic study supported by computations highlights these two separate mechanisms. Previously unreported reversible C-N ionization and a Pd(0)-catalyzed [3,3]-sigmatropic rearrangement were discovered. This study provides new reaction pathways for both π-allyl and sigmatropic rearrangements.
- Published
- 2021
- Full Text
- View/download PDF
13. Composite Ferroelectric Membranes Based on Vinylidene Fluoride-Tetrafluoroethylene Copolymer and Polyvinylpyrrolidone for Wound Healing.
- Author
-
Tverdokhlebova TS, Antipina LS, Kudryavtseva VL, Stankevich KS, Kolesnik IM, Senokosova EA, Velikanova EA, Antonova LV, Vasilchenko DV, Dambaev GT, Plotnikov EV, Bouznik VM, and Bolbasov EN
- Abstract
Wound healing is a complex process and an ongoing challenge for modern medicine. Herein, we present the results of study of structure and properties of ferroelectric composite polymer membranes for wound healing. Membranes were fabricated by electrospinning from a solution of vinylidene fluoride/tetrafluoroethylene copolymer (VDF-TeFE) and polyvinylpyrrolidone (PVP) in dimethylformamide (DMF). The effects of the PVP content on the viscosity and conductivity of the spinning solution, DMF concentration, chemical composition, crystal structure, and conformation of VDF-TeFE macromolecules in the fabricated materials were studied. It was found that as PVP amount increased, the viscosity and conductivity of the spinning solutions decreased, resulting in thinner fibers. Using FTIR and XRD methods, it was shown that if the PVP content was lower than 50 wt %, the VDF-TeFE copolymer adopted a flat zigzag conformation (TTT conformation) and crystalline phases with ferroelectric properties were formed. Gas chromatography results indicated that an increase in the PVP concentration led to a higher residual amount of DMF in the material, causing cytotoxic effects on 3T3L1 fibroblasts. In vivo studies demonstrated that compared to classical gauze dressings impregnated with a solution of an antibacterial agent, ferroelectric composite membranes with 15 wt % PVP provided better conditions for the healing of purulent wounds.
- Published
- 2020
- Full Text
- View/download PDF
14. Modification of PCL Scaffolds by Reactive Magnetron Sputtering: A Possibility for Modulating Macrophage Responses.
- Author
-
Stankevich KS, Kudryavtseva VL, Bolbasov EN, Shesterikov EV, Larionova IV, Shapovalova YG, Domracheva LV, Volokhova AA, Kurzina IA, Zhukov YM, Malashicheva AB, Kzhyshkowska JG, and Tverdokhlebov SI
- Subjects
- Macrophages, Polyesters, Tissue Engineering, Tissue Scaffolds
- Abstract
Direct current (DC) reactive magnetron sputtering is as an efficient method for enhancing the biocompatibility of poly(ε-caprolactone) (PCL) scaffolds. However, the PCL chemical bonding state, the composition of the deposited coating, and their interaction with immune cells remain unknown. Herein, we demonstrated that the DC reactive magnetron sputtering of the titanium target in a nitrogen atmosphere leads to the formation of nitrogen-containing moieties and the titanium dioxide coating on the scaffold surface. We have provided the possible mechanism of PCL fragmentation and coating formation supported by XPS results and DFT calculations. Our preliminary biological studies suggest that DC reactive magnetron sputtering of the titanium target could be an effective tool to control macrophage functional responses toward PCL scaffolds as it allows to inhibit respiratory burst while retaining cell viability and scavenging activity.
- Published
- 2020
- Full Text
- View/download PDF
15. Poly(ε-caprolactone) Scaffolds Doped with c-Jun N-terminal Kinase Inhibitors Modulate Phagocyte Activation.
- Author
-
Stankevich KS, Schepetkin IA, Goreninskii SI, Lavrinenko AK, Bolbasov EN, Kovrizhina AR, Kirpotina LN, Filimonov VD, Khlebnikov AI, Tverdokhlebov SI, and Quinn MT
- Abstract
The modulation of phagocyte responses is essential for successful performance of biomaterials in order to prevent negative outcomes associated with inflammation. Herein, we developed electrospun poly(ε-caprolactone) (PCL) scaffolds doped with the novel potent c-Jun N-terminal kinase (JNK) inhibitors 11 H -indeno[1,2- b ]quinoxalin-11-one oxime ( IQ-1 ) and 11 H -indeno[1,2- b ]quinoxalin-11-one O -( O -ethylcarboxymethyl) oxime( IQ-1E ) as a promising approach for modulating phagocyte activation. Optimized electrospinning parameters allowed us to produce microfiber composite materials with suitable mechanical properties. We found that embedded compounds were bound to the polymer matrix via hydrophobic interactions and released in two steps, with release mostly controlled by Fickian diffusion. The fabricated scaffolds doped with active compounds IQ-1 and IQ-1E effectively inhibited phagocyte inflammatory responses. For example, they suppressed human neutrophil activation by the biomaterials, as indicated by decreased neutrophil reactive oxygen species (ROS) production and Ca
2+ mobilization. In addition, they inhibited lipopolysaccharide (LPS)-induced NF-κB/AP-1 reporter activity in THP-1Blue cells and interleukin (IL)-6 production in MonoMac-6 cells without affecting cell viability. These effects were attributed to the released compounds rather than cell-surface interactions. Therefore, our study demonstrates that doping tissue engineering scaffolds with novel JNK inhibitors represents a powerful tool for preventing adverse immune responses to biomaterials as well as serves as a platform for drug delivery.- Published
- 2019
- Full Text
- View/download PDF
16. "Solvent/non-solvent" treatment as a method for non-covalent immobilization of gelatin on the surface of poly(l-lactic acid) electrospun scaffolds.
- Author
-
Goreninskii SI, Guliaev RO, Stankevich KS, Danilenko NV, Bolbasov EN, Golovkin AS, Mishanin AI, Filimonov VD, and Tverdokhlebov SI
- Subjects
- Biocompatible Materials pharmacology, Cell Adhesion drug effects, Cells, Cultured, Gelatin pharmacology, Humans, Microscopy, Fluorescence, Particle Size, Polyesters pharmacology, Stem Cells drug effects, Surface Properties, Biocompatible Materials chemistry, Gelatin chemistry, Polyesters chemistry, Solvents chemistry
- Abstract
In the present study, we report a simple and efficient method of gelatin immobilization on the surface of PLA electrospun fibers using pre-treatment with a mixture of toluene and ethanol allowing to form swelled surface layer followed by gelatin adsorption from its solution in PBS. Our results demonstrate that gelatin immobilization leads to a decrease in the water contact angle from 120° to 0°, enhances scaffold strength up to 50%, and doubles the number of adhered cells and their average area. We observed that the maximum amount of gelatin (0.07 ± 0.01 mg per cm
3 of the scaffold) was immobilized during the first five minutes of exposure to the gelatin solution. Modified scaffolds demonstrated increased strength., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
17. Flexible intramedullary nails for limb lengthening: a comprehensive comparative study of three nails types.
- Author
-
Bolbasov EN, Popkov DA, Kononovich NA, Gorbach EN, Khlusov IA, Golovkin AS, Stankevich KS, Ignatov VP, Bouznik VM, Anissimov YG, Tverdokhlebov SI, and Popkov AV
- Subjects
- Animals, Bone Lengthening methods, Bone and Bones, Calcium Phosphates, Cell Adhesion, Cell Differentiation, Coated Materials, Biocompatible chemistry, Durapatite chemistry, Humans, Materials Testing, Mesenchymal Stem Cells cytology, Mice, Mice, Inbred BALB C, Osteoblasts cytology, Osteogenesis, Spectroscopy, Fourier Transform Infrared, Steel, Surface Properties, X-Ray Diffraction, Bone Lengthening instrumentation, Bone Nails, External Fixators
- Abstract
This study aims to investigate the comparative study of calcium phosphate coatings for flexible intramedullary nails (FINs) used to lengthen long tubular bones. The presence of a calcium phosphate coating deposited by micro-arc oxidation (MAO) or a composite coating based on a co-polymer of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) and hydroxyapatite (HA) on the surface of the FIN significantly enhanced the regeneration of bone in the area of osteotomy during limb lengthening by combined osteosynthesis. The investigation of the physico-chemical properties of the FIN coated with calcium phosphate via MAO demonstrated that the improved bone tissue formation resulted from favourable conditions for adhesion, proliferation and differentiation of multipotent stem cells into osteoblasts on the coating surface. The composite coatings only stimulated the formation of bone tissue in vivo, primarily because of the piezoelectric properties of the VDF-TeFE co-polymer.
- Published
- 2019
- Full Text
- View/download PDF
18. The determination of enantiomer composition of 1-((3-chlorophenyl)-(phenyl)methyl) amine and 1-((3-chlorophenyl)(phenyl)-methyl) urea (Galodif) by NMR spectroscopy, chiral HPLC, and polarimetry.
- Author
-
Kuksenok VY, Shtrykova VV, Filimonov VD, Druganov AG, Bondarev AA, and Stankevich KS
- Abstract
For the first time, a method for enantiomer resolution of the anticonvulsant Galodif (1-((3-chlorophenyl)(phenyl)methyl) urea) by chiral HPLC was developed, whereas the enantiomeric composition of 1-((3-chlorophenyl)(phenyl)methyl) amine-precursor in Galodif synthesis-cannot be resolved by this method. However, starting 1-((3-chlorophenyl)(phenyl)methyl) amine quantitatively forms diastereomeric N-((3-chlorophenyl)(phenyl)methyl)-1-camphorsulfonamides in reaction with chiral (1R)-(+)- or (1S)-(-)-camphor-10-sulfonyl chlorides. The diastereomeric ratio of obtained camphorsulfonamides can be easily determined by NMR
1 H and13 C spectroscopy. The DFT calculations of specific rotation of Galodif enantiomers showed good agreement with experimental data. The absolute configuration of enantiomers was proposed for the first time., (© 2018 Wiley Periodicals, Inc.)- Published
- 2018
- Full Text
- View/download PDF
19. Surface modification of electrospun poly-(l-lactic) acid scaffolds by reactive magnetron sputtering.
- Author
-
Bolbasov EN, Maryin PV, Stankevich KS, Kozelskaya AI, Shesterikov EV, Khodyrevskaya YI, Nasonova MV, Shishkova DK, Kudryavtseva YA, Anissimov YG, and Tverdokhlebov SI
- Subjects
- Animals, Biocompatible Materials chemistry, Electrochemical Techniques, Hydrophobic and Hydrophilic Interactions, Male, Nitrogen chemistry, Plasma Gases pharmacology, Polyesters chemistry, Rats, Rats, Wistar, Surface Properties drug effects, Tissue Engineering, Biocompatible Materials pharmacology, Polyesters pharmacology, Prostheses and Implants, Subcutaneous Fat surgery, Tissue Scaffolds
- Abstract
In this study, we modified the surface of bioresorbable electrospun poly-(l-lactic) acid (PLLA) scaffolds by reactive magnetron sputtering of a titanium target under a nitrogen atmosphere. We examined the influence of the plasma treatment time on the structure and properties of electrospun PLLA scaffolds using SEM, XRF, FTIR, XRD, optical goniometry, and mechanical testing. It was observed that the coating formed did not change physicomechanical properties of electrospun PLLA scaffolds and simultaneously, increased their hydrophilicity. No adverse tissue reaction up to 3 months after subcutaneous implantation of the modified scaffolds was detected in in-vivo rat model. The rate of scaffold replacement by the recipient tissue in-vivo was observed to depend on the plasma treatment time., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
20. A new approach for the immobilization of poly(acrylic) acid as a chemically reactive cross-linker on the surface of poly(lactic) acid-based biomaterials.
- Author
-
Stankevich KS, Danilenko NV, Gadirov RM, Goreninskii SI, Tverdokhlebov SI, and Filimonov VD
- Subjects
- Animals, Cattle, Serum Albumin, Bovine chemistry, Acrylic Resins chemistry, Biodegradable Plastics chemistry, Drug Delivery Systems, Polyesters chemistry
- Abstract
A new approach for the immobilization of poly(acrylic) acid (PAA) as a chemically reactive cross-linker on the surface of poly(lactic) acid-based (PLA) biomaterials is described. The proposed technique includes non-covalent attachment of a PAA layer to the surface of PLA-based biomaterial via biomaterial surface treatment with solvent/non-solvent mixture followed by the entrapment of PAA from its solution. Surface morphology and wettability of the obtained PLA-PAA composite materials were investigated by AFM and the sitting drop method respectively. The amount of the carboxyl groups on the composites surface was determined by using the fluorescent compounds (2-(5-aminobenzo[d]oxazol-2-yl)phenol (ABO) and its acyl derivative N-(2-(2-hydroxyphenyl)benzo[d]oxazol-5-yl)acetamide (AcABO)). It was shown that it is possible to obtain PLA-PAA composites with various surface relief and tunable wettability (57°, 62° and 66°). The capacity of the created PAA layer could be varied from 1.5nmol/cm
2 to 0.1μmol/cm2 depending on the modification conditions. Additionally, using bovine serum albumin (BSA) it was demonstrated that such composites could be modified with proteins with high binding density (around 0.18nmol/cm2 ). Obtained fluoro-labeled PLA-PAA materials, as well as PLA-PAA composites themselves, are valuable since they can be used for biodegradable polymer implants tracking in living systems and as drug delivery systems., (Copyright © 2016 Elsevier B.V. All rights reserved.)- Published
- 2017
- Full Text
- View/download PDF
21. Surface modification of biomaterials based on high-molecular polylactic acid and their effect on inflammatory reactions of primary human monocyte-derived macrophages: perspective for personalized therapy.
- Author
-
Stankevich KS, Gudima A, Filimonov VD, Klüter H, Mamontova EM, Tverdokhlebov SI, and Kzhyshkowska J
- Subjects
- Cells, Cultured, Cytokines immunology, Elastic Modulus, Hardness, Humans, Macrophage Activation drug effects, Macrophages drug effects, Materials Testing, Molecular Weight, Patient-Centered Care methods, Polyesters, Structure-Activity Relationship, Surface Properties, Tensile Strength, Biocompatible Materials chemistry, Biocompatible Materials pharmacology, Lactic Acid chemistry, Lactic Acid pharmacology, Macrophage Activation immunology, Macrophages immunology, Polymers chemistry, Polymers pharmacology
- Abstract
Polylactic acid (PLA) based implants can cause inflammatory complications. Macrophages are key innate immune cells that control inflammation. To provide higher biocompatibility of PLA-based implants with local innate immune cells their surface properties have to be improved. In our study surface modification technique for high-molecular PLA (MW=1,646,600g/mol) based biomaterials was originally developed and successfully applied. Optimal modification conditions were determined. Treatment of PLA films with toluene/ethanol=3/7 mixture for 10min with subsequent exposure in 0.001M brilliant green dye (BGD) solution allows to entrap approximately 10(-9)mol/cm(2) model biomolecules. The modified PLA film surface was characterized by optical microscopy, SERS, FT-IR, UV and TG/DTA/DSC analysis. Tensile strain of modified films was determined as well. The effect of PLA films modified with BGD on the inflammatory reactions of primary human monocyte-derived macrophages was investigated. We developed in vitro test-system by differentiating primary monocyte-derived macrophages on a coating material. Type 1 and type 2 inflammatory cytokines (TNFα, CCL18) secretion and histological biomarkers (CD206, stabilin-1) expression were analyzed by ELISA and confocal microscopy respectively. BGD-modified materials have improved thermal stability and good mechanical properties. However, BGD modifications induced additional donor-specific inflammatory reactions and suppressed tolerogenic phenotype of macrophages. Therefore, our test-system successfully demonstrated specific immunomodulatory effects of original and modified PLA-based biomaterials, and can be further applied for the examination of improved coatings for implants and identification of patient-specific reactions to implants., (Copyright © 2015. Published by Elsevier B.V.)
- Published
- 2015
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.