Solujen kasvun vertailu tekstiili-skaffoldeilla in vitro kudosteknologisiin sovelluksiin

Biotextiles are fibrous structures created from synthetic or natural materials, which are used as biodegradable temporary scaffolds in tissue engineering. The function of such cell-seeded devices is to heal or replace damaged organs or tissues. Biocompatibility and retention of mechanical properties in the relatively hostile environment is required from the fiber materials. Porosity, pore sizes and pore shapes affect cell coverage and distribution on the scaffolds. Textile manufacturing techniques provide a vast variety of available structures in both small and large scale production. The aim of this thesis was to compare cell viability and distribution on textile scaffolds. For this purpose melt spinning method was used to process poly-L/D-lactide 96/4 (PLDLA 96/4) fibers. A 36-week hydrolytic degradation experiment was conducted for the gamma irradiated fibers to evaluate retention of mechanical properties and changes in crystallinity and thermal properties. Tensile testing method was used for mechanical properties and differential scanning calorimetry (DSC) for the two last mentioned. The fibers were used to manufacture braided, knitted and woven fabrics. Heat sealing and compression at elevated temperature was used to prepare multi-layered scaffolds with approximately 1 mm thickness. Recovery after heat treatment and swelling in cell culture medium was evaluated for the scaffolds. Human urothelial cells (hUCs) and human foreskin fibroblasts (hFFs) were used in the cell culture experiment. Live/Dead analysis and crystal violet staining were used to assess cell viability and distribution. Tensile strength of the PLDLA 96/4 fibers decreased during degradation as did strain at maximum load. Crystallinity increased with a few percent. Glass transition temperature decreased, as was predicted based on previous studies. Unexpectedly, the melting temperature showed a slight increase during degradation. In the recovery and swelling experiments, unwanted changes were not observed. The cell culture experiment demonstrated good biocompatibility for the fibers. After 2 weeks of incubation, the less porous braided and woven scaffolds had the most attached hUC and hFF cells. The large pores of knitted scaffolds remained mostly cell free for both cell types throughout the experiment. The experiments conducted for this thesis demonstrated that PLDLA 96/4 fiber bundles can be processed into biodegradable braided, knitted and woven textile scaffolds. These structures support viability of cells in vitro. The number of attached cells was the largest in braided and woven structures that had significantly smaller pores in comparison to knitted scaffolds

Impact of oxidation-induced ordering on the electrical and mechanical properties of a polythiophene co-processed with bistriflimidic acid

The interplay between the nanostructure of a doped polythiophene with oligoether side chains and its electrical as well as mechanical properties is investigated. The degree of order of the polymer is found to strongly vary when co-processed with bistriflimidic acid (H-TFSI). The neat polythiophene as well as strongly oxidized material are largely disordered while intermediate concentrations of H-TFSI give rise to a high degree of π-stacking. The structural disorder of strongly oxidized material correlates with a decrease in the kinetic fragility with H-TFSI concentration, suggesting that positive interactions between TFSI anions and the polymer reduce the ability to crystallize. The electrical conductivity as well as the Young\u27s modulus first increase upon the addition of 4-10 mol% of H-TFSI, while the loss of π-stacking observed for strongly oxidized material more significantly affects the latter. As a result, material comprising 25 mol% H-TFSI displays an electrical conductivity of 58 S cm−1 but features a relatively low Young\u27s modulus of only 80 MPa. Decoupling of the electrical and mechanical properties of doped conjugated polymers may allow the design of soft conductors that are in high demand for wearable electronics and bioelectronics

Building blocks of microphysiological system to model physiology and pathophysiology of human heart

Microphysiological systems (MPS) are drawing increasing interest from academia and from biomedical industry due to their improved capability to capture human physiology. MPS offer an advanced in vitro platform that can be used to study human organ and tissue level functions in health and in diseased states more accurately than traditional single cell cultures or even animal models. Key features in MPS include microenvironmental control and monitoring as well as high biological complexity of the target tissue. To reach these qualities, cross-disciplinary collaboration from multiple fields of science is required to build MPS. Here, we review different areas of expertise and describe essential building blocks of heart MPS including relevant cardiac cell types, supporting matrix, mechanical stimulation, functional measurements, and computational modelling. The review presents current methods in cardiac MPS and provides insights for future MPS development with improved recapitulation of human physiology.Peer reviewe

Recent Advances and Prospects in the Differentiation of Pancreatic Cells From Human Embryonic Stem Cells

Recent studies with human embryonic stem (hES) cells have established new protocols for substantial generation of pancreatic progenitors from definitive endoderm. These findings add to the efficient derivation of definitive endoderm, which is controlled by Wnt and Nodal pathways, and delineate a step forward in the quest for alternative β-cell sources. It also indicates that critical refining of the available strategies might help define a universal protocol for pancreatic differentiation applicable to several cell lines, therefore offering the possibility for transplantation of immune-matched or patient-specific hES–derived β-cells. We appraise here the fundamental role that bone morphogenetic protein, fibroblast growth factor, and retinoid signaling play during pancreas development, and describe a fundamental emergence of their combination in recent studies that generated pancreatic cells from hES cells. We finally enumerate some prospects that might improve further differentiation of the progenitor cells into functional β-cells needed in diabetes cell therapy

Solujen kasvun vertailu tekstiili-skaffoldeilla in vitro kudosteknologisiin sovelluksiin

Biotextiles are fibrous structures created from synthetic or natural materials, which are used as biodegradable temporary scaffolds in tissue engineering. The function of such cell-seeded devices is to heal or replace damaged organs or tissues. Biocompatibility and retention of mechanical properties in the relatively hostile environment is required from the fiber materials. Porosity, pore sizes and pore shapes affect cell coverage and distribution on the scaffolds. Textile manufacturing techniques provide a vast variety of available structures in both small and large scale production. The aim of this thesis was to compare cell viability and distribution on textile scaffolds. For this purpose melt spinning method was used to process poly-L/D-lactide 96/4 (PLDLA 96/4) fibers. A 36-week hydrolytic degradation experiment was conducted for the gamma irradiated fibers to evaluate retention of mechanical properties and changes in crystallinity and thermal properties. Tensile testing method was used for mechanical properties and differential scanning calorimetry (DSC) for the two last mentioned. The fibers were used to manufacture braided, knitted and woven fabrics. Heat sealing and compression at elevated temperature was used to prepare multi-layered scaffolds with approximately 1 mm thickness. Recovery after heat treatment and swelling in cell culture medium was evaluated for the scaffolds. Human urothelial cells (hUCs) and human foreskin fibroblasts (hFFs) were used in the cell culture experiment. Live/Dead analysis and crystal violet staining were used to assess cell viability and distribution. Tensile strength of the PLDLA 96/4 fibers decreased during degradation as did strain at maximum load. Crystallinity increased with a few percent. Glass transition temperature decreased, as was predicted based on previous studies. Unexpectedly, the melting temperature showed a slight increase during degradation. In the recovery and swelling experiments, unwanted changes were not observed. The cell culture experiment demonstrated good biocompatibility for the fibers. After 2 weeks of incubation, the less porous braided and woven scaffolds had the most attached hUC and hFF cells. The large pores of knitted scaffolds remained mostly cell free for both cell types throughout the experiment. The experiments conducted for this thesis demonstrated that PLDLA 96/4 fiber bundles can be processed into biodegradable braided, knitted and woven textile scaffolds. These structures support viability of cells in vitro. The number of attached cells was the largest in braided and woven structures that had significantly smaller pores in comparison to knitted scaffolds

Kolmannen ja neljännen kompressioluokan painesukat : Valmistusmenetelmät, rakenteet ja paineen mallintaminen

Opinnäytetyön tarkoitus oli koota tietoa painesukkien valmistamisesta, rakenteista, niiden valmistukseen käytetyistä raaka-aineista ja puristuspaineen mallintamisesta. Sisällön tavoitteena on tukea Tampereen teknillisessä yliopistossa käynnissä olevaa projektia. Opinnäytetyössä keskitytään kolmannen ja neljännen kompressioluokan painesukkiin. Jalkojen laskimo-oireita hoitavien ja ennaltaehkäisevien painesukkien toiminta perustuu puristuspaineeseen, joka on suurimmillaan nilkan kohdalla ja laskee siitä jalkaa ylöspäin noustessa. Oikeanlainen painejakauma on erittäin oleellinen painesukan lääkinnällisen tehokkuuden kannalta, mutta jalkojen yksilöllisten erojen vuoksi hoidon kannalta te-hokkaan paineen luominen ja sen ylläpitäminen on haastavaa. Painesukat jaotellaan kompressioluokkiin ja yleisesti käytössä oleva eurooppalainen esistandardi jakaa pai-nesukat viiteen kompressioluokkaan. Kolmannen ja neljännen kompressioluokkien pai-nesukkia kutsutaan myös lääkinnällisiksi kompressiosukiksi. Ne määrää yleensä lääkäri ja niitä käytetään vaikeisiin vaivoihin. Suurin osa painesukista on kudeneuloksia ja ne valmistetaan pyörö- ja tasoneuloksina. Yleisesti käytettyjä sidoksia ovat muun muassa interlock-sidos, sileä neulos ja joustin-neulos. Puristuspaine luodaan elastisen vuorilangan avulla, joka voidaan valmistaa ela-taanista, elastodieenistä tai luonnonkumista, kun muut langat valmistetaan puuvillasta ja polyamidista. Antimikrobisten ominaisuuksien saamiseksi lanka tai kuidut voidaan päällystää hopealla. Painesukkien peseminen ja käyttö vaikuttavat painejakaumaan ja puristuspaineen suuruuteen. Puristuspaineen laskennallinen mallintaminen tapahtuu parhaiten Laplacen yhtälön avulla, kun lasketaan puristuspaine tietyssä pisteessä. Tuo-tekehitystyön haaste on yksilöiden ja yksittäisten tapausten erojen ja tarpeiden huomi-oon ottaminen, jotta painejakaumat ja puristuspaineen suuruudet olisivat hoidon kannal-ta optimaalisia jokaiselle potilaalle.The purpose of this study was to gather information about manufacturing, structures, raw-materials and pressure modeling of compression stockings. The objective is to sup-port a ongoing project in Tampere University of Technology. The focus is on compres-sion stockings of third and fourth compression classes. The function of compression stockings is based on pressure, that gradually decreases from the ankle up. For medical purposes it is important for the pressure reduction to be accurate. Because of individual differences of human legs it is challenging to create and maintain effective pressure and pressure reduction for the treatment. Compression stockings can be used to prevent and treat venous diseases in legs. Compression stock-ings are devided into compression classes. The Commonly used European prestandard for Medical compression hosiery uses five compression classes. Compression stockings of the third and fourth compression classes are usually prescribed by a physician and are used for serious illnesses. Most compression stockings are weft knitted and made as circular or flat knitted fabrics. Common stitches used are interlock, single and rib. The pressure is created with a elastic inlay-yarn made of elastane, elastodiene or natural gum. Other yarns are made of cotton or polyamide. To achieve antimicrobial activity the yarns or fibers can be coated with silver. Washing and usage of the compression stockings will affect the pressure reduction and amount of applied pressure. Best result for mathematical modeling of applied pressure is achieved when Laplaces law is used to compute applied pressure in a single point. The biggest challenge in the field is to take into consideration the differ-ences between individual patients and their needs to achieve optimal applied pressures and pressure distribution

Exploring orange peel treatment with deep eutectic solvents and diluted organic acids

The disintegration of orange peel waste in deep eutectic solvents and diluted organic acids is presented in this work. The albedo and flavedo layers of the peel were studied separately, showing faster disintegration of the latter. Addition of water to the deep eutectic solvents lowered the amount of remaining solids and improved the disintegration times. These improvements are subscribed to a decrease in viscosity upon deep eutectic solvent dilution. Each of the individual deep eutectic solvent components were diluted and subjected to the same disintegration tests. The corresponding diluted organic acids showed similar orange peel disintegration performance as the tested deep eutectic solvents, whereas dilutions of the other counterparts did not show any activity. Hence, the active deep eutectic solvent components during orange peel treatment are considered to be their organic acids. Flavonoids and essential oils were released during the treatment, offering new opportunities for the development of orange peel waste valorisation routes

Tailoring of the physical and mechanical properties of biocompatible graphene oxide/gelatin composite nanolaminates : Via altering the crystal structure and morphology

Despite substantial progress being made relating to 2D-nanofiller-based composite nanolaminates, the fabrication of composite nanolaminates with enhanced ductility and toughness is still challenging. In this study, layered structure graphene oxide (GO)/gelatin powder (GP) composites nanolaminates with enhanced ductility and toughness have been achieved by a simple vacuum filtration of aqueous dispersion of GO/GP composite solution containing 5 wt% of GO. The composite film containing 5 wt% GO shows outstanding improvement of 200% in the stress at break value, with simultaneous enhancement of 52% of the strain at break value compared to GP film. A significant improvement in toughness from 2.2 MJ m-3 to 9.5 MJ m-3 is observed in the composite film containing 5 wt% GO. These significant enhancements of the mechanical properties of the composite film are obtained via the formation of an intercalated nanolaminate structure, H-bonding interactions, and the tailoring of the crystal structure of GP in the composite film, as proved via field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, and wide-angle X-ray diffraction studies. The growing of fibroblast cells on the composite films signifies that they are not cytotoxic. These GO/GP composites with significant mechanical properties and biocompatibility are very promising for various biomedical applications. This journal ispublishedVersionPeer reviewe

Synthesis, structures and luminescence properties of two gallium(III) complexes with 5,7-dimethyl-8-hydroxyquinoline

<p>Luminescent gallium(III) complexes featuring 5,7-dimethyl-8-hydroxyquinoline (DimOx) are systematically compared and their structural features are correlated with their photophysical properties. The two complexes are chemically identical; however, contain various number of solvent molecules in the crystalline lattice which is representative of the bulk material confirmed by both nuclear magnetic resonance and elemental analysis. Detailed structural comparisons highlight the effect which the solvent molecules have on the intra- and intermolecular interactions. A distinct number of interactions are found for the gallium complex (<b>1</b>) containing more than one solvent molecule for unit cell. Variation in complex morphology is similarly observed via SEM micrographs. The distinct luminescent properties of the two gallium complexes appear directly related to octahedral coordination of the 8-hydroxyquinoline ligand as well as the number of identical coordinated solvent molecules.</p