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Intelligent nanofibres functionalized with growth factors and blood derivatives for dermatology applications
Vocetková, Karolína ; Amler, Evžen (advisor) ; Rosina, Jozef (referee) ; Arenberger, Petr (referee)
Platelet derivatives are an attractive source of natural growth factors and they are widely used in various tissue engineering and regenerative medicine applications. The aim of this study was to optimize cell culture conditions using platelet lysate and to develop platelet-functionalized fibrous scaffolds as a controlled drug delivery system for native growth factors. Fibrous scaffolds were prepared by electrostatic and centrifugal spinning of PCL and they were functionalized by the platelets by surface adhesion or their encapsulation using emulsion spinning techniques. The cell culture study determined the 7% platelet lysate to be the optimum concentration as a medium supplement in keratinocyte and fibroblast culture. Additionally, following surface adhesion of the platelets to PCL electrospun nanofibres, the platelets were activated due to their contact with the nanofibre nanotopography, resulting in formation of fibrin network. Fibrin served as a reservoir of the growth factors, prolonging the half-time of EGF release to 1.7 days. Such platelet-functionalized samples fostered proliferation of keratinocytes, fibroblasts and melanocytes. Furthermore, adhesion of platelets to centrifugally spun nanofibrous scaffolds resulted in almost two-fold increase in the amount of immobilized platelet-derived...
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Nanofibrous Separators for Lithium-Ion Batteries
Pléha, David ; Míka, Martin (referee) ; Janderka,, Pavel (referee) ; Novák, Vítězslav (advisor)
Nanofibrous separators use in lithium-ion batteries brings many advantages. In contrast to contemporary used commercial separators, nanofibrous ones exhibit higher temperature resistance,ionic conductivity and higher electrolyte uptake. Better ionic conductivity is ensured by porous structure and large specific surface. Fibers creates channels for the ionic species motion. Amorphous texture of nanofibers allows quick lithium ionic species motion within the polymeric matrix of separator. Furthermore, these separators exhibit higher volume of uptaken electrolyte. Further advantage of electrospinned nanofibrous separators are both high porosity and chemical stability.
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Plasma modification of functionalized PVA nanofibers for the enhancement of mesenchymal stem cell adhesion, viability and proliferation.
Bezděková, Dagmar ; Amler, Evžen (advisor) ; Gášková, Dana (referee)
Electrospinning is widely used technique to produce nanoscale constructs for tissue engineering. This technique can be used to spin wide range of polymers. One of them is polyvinyl alcohol (PVA), which has very good properties for use in this field. PVA is nontoxic, has good mechanical strength and it's degradable and biocompatible. Electrospun PVA nanofibers have limitations because of their -OH side groups. These groups cause solubility of PVA in water. The solubility can be adjusted with crosslinking techniques, but PVA still remains very hydrophilic, which is causing low adhesion of cells. In recent research we decided to reduce the hydrophilicity of PVA using plasma modification. Polymer modification with cold plasma is an economic and quite simple process to change the surface chemistry without side effects that come with conventional chemical treatment. With radical, formed by discharge, we have deposited hydrocarbons on the PVA surface and we rapidly increased hydrophobicity of the polymer surface. The change of surface chemistry has only a little effect on the fiber morphology. The increase of hydrophobicity allowed better adhesion of mesenchymal stem cells on plasma modified PVA as compared to non-modified PVA and a huge change in cell morphology was observed. These changes suggest that we...
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Characterization of functionalized fibres for mesenchymal stem cells cultivation and differentiation
Greplová, Jarmila ; Amler, Evžen (advisor) ; Rosina, Jozef (referee)
Modification of nanofibers is an actual trend in tissue engineering. Polyvinylacohol (PVA) is nontoxic and biodegradable polymer suitable for preparation of submicron fibers by electrospinning. Main disadvantage of PVA fibers is rapid degradation in aqueous environment. On the other hand surface of fibers contains free hydroxyl group that could be chemically modified. In recent work, chemical modification of PVA nanofibers prepared by needleless electrospinning was investigated. Polyethylenglykol (PEG) linker was introduced to the fiber surface by acylation (PVA-PEG) and further modified by biotin (PVA-PEG-b) as a function agent. Process of chemical modification does not affected fibrous morphology of samples. Interestingly, linkage of PEG-b linker promoted stability of PVA in aqueous environment. PVA-PEG-b sample was stable for 41 days. Stability of samples was strongly dependent on amount of introduced PEG-b linker, thus proposed method of modification allows to prepare nanofibers of different solubility. Additionally, biocompatibility of chemically modified nanofibers with both mesenchymal stem cells (MSC) and chondrocytes was determined. Proliferation of both cell types was not sufficient and number of cells decreased in time, probably because of high hydrophility of modified PVA scaffold. To...
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Application of nanofiber scaffolds for vesel regeneration
Bezděková, Dagmar ; Amler, Evžen (advisor) ; Holzerová, Kristýna (referee)
Although plenty of systems for vessel regeneration have been developed, no system is successful in small diameter (under 6 mm) vessel replacement yet. Synthetic materials, such as Dacron and ePTFE, have good results in large vessels replacement, but they cause thrombosis in small vessels. In addition, they are not degradable and do not allow a natural remodeling of the vessel system. Furthemore, endothelial cells, which are essential for creating natural antithrombogenic endothelium, do not adhere on these materials, as well as smooth muscle cells. Decellularized xenogenic material is the non-synthetic alternative for vessel regeneration. Appropriate detergent removes donor's cells and only extracellular matrix remains, which is able to host acceptor's cells. The main disadvantages of this system are difficulties with animal's nurture and structure violations after detergent is used. It appears that electrospun materials are the best alternative. The relatively simple process can be modified in many ways and provides then a scaffold, which mimics extracellular matrix. A big advantage of this process is the possibility to incorporate bioactive substances into a fiber. The substances serve there as an attractant for blood cells or as an anticoagulation factor. In combination with the progenitor cells seems...
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The Rheological Behavior of Polymer Solutions Suitable for Electrospinning
Divínová, Nikol ; Voráč,, Zbyněk (referee) ; Chamradová, Ivana (advisor)
This diploma thesis deals with preparation and characterization of aqueous solutions of polyvinyl alcohol suitable for electrospinning. In the theoretical part method of electrospinning is described, including parameters which influence this process. Literary research also includes a chapter about rheology, which deals with the rheological properties of polymers, specifically PVA. The experimental part describes the preparation and rheological study of of aqueous solutions of polyvinyl alcohol, which were then spun. The morphology of prepared nanofibers was studied by using scanning electron microscopy (SEM). The effect of molecular weight, the solvent, concentration of solution, rheological properties, electrical conductivity and surface tension on the spinability, diameter and morphology of nanofibers is discussed.
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Heating Module for the Electrospinning Electrode
Lukesle, Václav ; Musil, Vladislav (referee) ; Pokorný,, Marek (advisor)
The thesis deals with the principal heating design of the electrospinning electrode. These electrodes are fed with high voltage (tens of kV), which is an essential part of the device for the nanofibres production. This thesis presents the research of possible solutions of the heating and also it analyzes some principles of the nanofibre production. Furthermore, the work presents electrical schematics and PCB of the heating module. The aim of this work is to propose such a solution of heating that makes spinning from melt realizable in the device for 4SPIN ® nanofibres production.
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