Production of Nonwoven Fabrics by Using Silk Fibres via Electrospinning Technique
Title Alternative:Příprava netkaných textilií s obsahem hedvábných vláken získaných metodou elektrostatického zvlákňování
Loading...
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Technická Univerzita v Liberci
Abstract
Tato dizertační práce se zabývá výrobou nanovlákenných vrstev z fibroinu z přírodního hedvábí (silk fibroin, dále jen SF), a směsí SF s polykaprolaktonem (PCL) připravené metodou bezjehlového elektrostatického zvlákňování (technologie NanospiderTM). V procesu zvlákňování byla zkoumána inovativní metoda přípravy zvlákňovacího roztoku SF za použití rozpouštědla ve formě směsi kyseliny mravenčí a chloridu vápenatého. Výzkum byl zaměřen na vliv koncentrace roztoku fibroinu, použitého napětí a vzdálenosti elektrod na morfologii vzniklých vláken i na samotný proces zvlákňování. In vitro testy za použití 3T3 myších fibroblastů, lidských kožních fibroblastů, MG 63 osteoblastů a lidských endotelových buněk z pupečníkové žíly byly zvoleny pro hodnocení biokompatibility vlákenných vrstev. Dále byla sledována pevnost v tahu a hydrofilita spolu s dalšími fyzikální vlastnostmi vytvořených vlákenných vrstev. Rozpouštědlový systém, který sestával z kyseliny mravenčí a chloridu vápenatého, byl schopen rozpustit SF za pokojové teploty při použití poměru 0,25 g chloridu vápenatého na 1 g SF. Tento rozpouštědlový systém je vhodný pro nanovláken metodou elektrostatického zvlákňování na poloprovozní jednotce Superlab.Průměr vláken, získaných za použití zmíněného rozpouštědlového systému, se pohyboval v rozmezí 100 nm až 2400 nm v závislosti na parametrech zvlákňovacího procesu. Pro přípravu nanovláken prostřednictvím bezjehlového zvlákňování byla optimální koncentrace SF od 8% hmot. do 12% hmot. S rostoucí koncentrací a napětím se zlepšovala zvláknitelnost roztoku a produktivita zvlákňovacího procesu. Zatímco vlákna ze samotného SF měla špatné mechanické vlastnosti, ukázalo se, že ve směsi s PCL docházelo k výraznému zlepšení. Průměr směsných nanovláken byl nižší a pružnost těchto vrstev byla vyšší než v případě čistého SF. Se zvyšujícím se podílem PCL však docházelo ke zhoršení zvlákňovacího procesu.Nanovlákenné vrstvy z čistého SF a ze směsi SF a PCL jsou materiály s potenciálem pro využití v biomedicínských aplikacích, jako jsou kryty ran nebo tkáňové inženýrství zaměřené na regeneraci kostních tkání. In vitro testy s živými buňkami, především MG 63 osteoblasty, potvrdily velmi dobrou biokompatibilitu připravených nanovlákenných vrstev. PCL/SF nanovlákna navíc našla své uplatnění jako nosič pro imobilizaci lakázy Trametes versicolor. Nejen že se tato směsná nanovlákna uplatnila jako nosič pro enzym, ale zároveň měla imobilizovaná lakáza velmi dobré výsledky v oblasti degradace endokrinních disruptorů (bisfenol A a 17?-ethinyl estradiol). Imobilizace lakázy na PCL/SF nanovlákna má potenciál pro využití při čištění odpadních vod.
This dissertation was concerned and focused a fabrication of a silk fibroin (SF) nonwoven sheet and its blending with polycaprolactone (PCL) via a needleless electrospinning technique (technology Nanospider?). The procedure concentrated on a novel method for the preparation of a spinning solution from silk fibroin, by using a mixture of formic acid and calcium chloride as a solvent. The role of concentration of silk fibroin solution, applied voltage and spinning distance are investigated as a function of the morphology of obtained fibres and the spinning performance of the electrospinning process. Biocompatibility of the obtained fibre sheets that resulted from the experiment was evaluated by in vitro testing method, with 3T3 mouse fibroblasts, normal human dermal fibroblasts, MG 63 osteoblasts and human umbilical vein endothelial cells. Tensile strength and hydrophilicity as well as physical properties evaluation of electrospun fibre sheets were performed. The solvent system consists of formic acid and calcium chloride that can dissolve SF at room temperature, a rate of 0.25 gram of calcium chloride per 1 gram of silk fibroin is required to obtain the completely dissolved silk fibroin solution. This solvent system could be potentially employed and used for a preparation of silk fibroin solution for a large-scale production of silk nanofibres, with a needleless electrospinning method. The diameters of the silk electrospun fibres obtained from the formic acid-calcium chloride solvent system had a diameter ranging from 100 nm to 2400 nm depending upon the spinning parameters. Concentrations of silk fibroin in the range of 8 wt% to 12 wt% seem to be a suitable concentration for the preparation of a nanofibre sheet, with needleless electrospinning. Furthermore, increasing the concentration of the silk fibroin solution and the applied voltage improved the spinning ability and the spinning performance in needleless electrospinning. Pure silk fibroin electrospun fibres have poor mechanical properties, while research indicates blending PCL with silk fibroin can improve mechanical properties significantly. The diameters of the blended SF/PCL electrospun fibres were smaller and the elasticity was greater than the pure SF elctrospun fibres. However, an increase of PCL content in the blended solution affected the spinning performance of the process. The spinning performance of the electrospinning process tends to decrease as the polycaprolactone content in the blended solution increases.Silk electrospun fibre sheets and its blends with PCL are promising materials for the biomedical applications such as wound dressing and bone tissue engineering. In vitro tests with living cells show very good biocompatibility of the electrospun fibre sheets, especially with MG 63 osteoblasts. In addition, the PCL/SF blend fibre sheets have been applied as supports for immobilization of laccase from Trametes versicolor. The blended fibre sheet were suitable for enzyme immobilization and the blended fibre sheets with the laccase immobilized showed very good results in the degradation of endocrine disrupting chemicals (bisphenol A and 17?-ethinyl estradiol). The laccase immobilization onto the PCL/SF blend fibre sheets seems to be a promising system for bioremediation of wastewater treatment.
This dissertation was concerned and focused a fabrication of a silk fibroin (SF) nonwoven sheet and its blending with polycaprolactone (PCL) via a needleless electrospinning technique (technology Nanospider?). The procedure concentrated on a novel method for the preparation of a spinning solution from silk fibroin, by using a mixture of formic acid and calcium chloride as a solvent. The role of concentration of silk fibroin solution, applied voltage and spinning distance are investigated as a function of the morphology of obtained fibres and the spinning performance of the electrospinning process. Biocompatibility of the obtained fibre sheets that resulted from the experiment was evaluated by in vitro testing method, with 3T3 mouse fibroblasts, normal human dermal fibroblasts, MG 63 osteoblasts and human umbilical vein endothelial cells. Tensile strength and hydrophilicity as well as physical properties evaluation of electrospun fibre sheets were performed. The solvent system consists of formic acid and calcium chloride that can dissolve SF at room temperature, a rate of 0.25 gram of calcium chloride per 1 gram of silk fibroin is required to obtain the completely dissolved silk fibroin solution. This solvent system could be potentially employed and used for a preparation of silk fibroin solution for a large-scale production of silk nanofibres, with a needleless electrospinning method. The diameters of the silk electrospun fibres obtained from the formic acid-calcium chloride solvent system had a diameter ranging from 100 nm to 2400 nm depending upon the spinning parameters. Concentrations of silk fibroin in the range of 8 wt% to 12 wt% seem to be a suitable concentration for the preparation of a nanofibre sheet, with needleless electrospinning. Furthermore, increasing the concentration of the silk fibroin solution and the applied voltage improved the spinning ability and the spinning performance in needleless electrospinning. Pure silk fibroin electrospun fibres have poor mechanical properties, while research indicates blending PCL with silk fibroin can improve mechanical properties significantly. The diameters of the blended SF/PCL electrospun fibres were smaller and the elasticity was greater than the pure SF elctrospun fibres. However, an increase of PCL content in the blended solution affected the spinning performance of the process. The spinning performance of the electrospinning process tends to decrease as the polycaprolactone content in the blended solution increases.Silk electrospun fibre sheets and its blends with PCL are promising materials for the biomedical applications such as wound dressing and bone tissue engineering. In vitro tests with living cells show very good biocompatibility of the electrospun fibre sheets, especially with MG 63 osteoblasts. In addition, the PCL/SF blend fibre sheets have been applied as supports for immobilization of laccase from Trametes versicolor. The blended fibre sheet were suitable for enzyme immobilization and the blended fibre sheets with the laccase immobilized showed very good results in the degradation of endocrine disrupting chemicals (bisphenol A and 17?-ethinyl estradiol). The laccase immobilization onto the PCL/SF blend fibre sheets seems to be a promising system for bioremediation of wastewater treatment.