DRAWING: Příprava scaffoldů pro regeneraci nervové tkáně
Title Alternative:DRAWING: Fabrication of Scaffolds for Neural Tissue Engineering
Loading...
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Materiály založené na orientovaných vláknech mají velký potenciál pro využití v tkáňovém inženýrství a to zejména u tkání, kde je organizace mezibuněčné hmoty zcela zásadní pro funkčnost tkáně. Velmi vhodnou metodou pro tyto aplikace je metoda drawing. Ten je založen na mechanickém tažení polymerního roztoku z kapky polymeru umístěné na podložce, což vede k vytvoření vlákna o definovaných geometrických charakteristikách. Pro tyto účely byl navržen a vyvinut laboratorní přístroj, který umožňuje tažení vláken za stálých podmínek. Výsledky ukazují, že změnou rychlostí tažení vláken a změnou koncentrací polymerních roztoků lze ovlivnit a regulovat průměr vláken a zároveň i distribuci jejich průměrů. Z in vitro experimentů je patrné, že orientovaná vlákna ovlivňují směr růstu buněk a jejich orientaci na scaffoldu ve směru orientace vláken. Na základě těchto experimentů byly tyto scaffoldy dále funkcionalizovány polypyrrolem, čímž se prokázala jejich univerzálnost pro použití v tkáňovém inženýrství. Výsledky z in vitro experimentů s popyrrolovanými vlákny ukazují, že polypyrrole zvyšuje biokompatibilitu vláken. Popyrrolovaná vlákna byla dále použita pro přípravu nových kompozitních míšních můstků, které byly testovány in vitro a in vivo. Výsledky z in vitro experimentů ukazují, že orientovaná vlákna podporují vedení a růst axonů a orientaci axonův těsném kontaktu okolo vláken. Tento jev je ještě více patrný, pokud jsou vlákna potažená polypyrrolem. In vivo experimenty byly provedeny na myších, jimž byly můstky implantovány do mích. Hodnocení pro-zánětlivých a apoptotických markerů naznačuje, že vlákenné míšní můstky jsou neimunogenní. Tyto výsledky ukazují aktivaci imunitní reakce, která je zodpovědná za procesy hojení v těle, a to u obou vlákenných míšních můstků. Míšní můstky obsahující PCL orientovaná vlákna dokonce vykazují vyšší infiltraci axonů do můstků oproti kontrole bez vláken. Okolo 20 % těchto axonů je myelinizovaných, 75 % z tohoto myelinu je odvozeno od Schwanových buněk. Na druhou stranu, u míšních můstků s popyrrolovanými vlákny je infiltrace axonů do můstků oproti kontrole nižší. Nicméně výsledky ukazují, že orientovaná vlákna zvyšují infiltraci axonů do míšních můstků a že kombinace dostupných přístupů a metod funkcionalizace materiálů budou volbou do budoucna pro tkáňové inženýrství nervové tkáně.
Materials based on orientated fibers have great potential for use in tissue engineering for tissues, where the arrangement of extracellular matrix is fundamental for tissue functionality. The drawing method is extremely suitable method for such applications. It is based on mechanical pulling of a polymer solution out of its base droplet, resulting in a single solidified fiber of determined geometrical characteristics. A new machine designed for lab scale drawing was invented enabling a repeatable quality of drawing conditions. The results demonstrate that by changing the speed of drawing and polymer solution concentration it is possible to influence and define the fiber diameter and its distribution. From the in vitro experiments, it is evident that the aligned fibers guide the cell growth in the direction of the fibers. Moreover, the prepared fibers were functionalized with polypyrrole as an example of their versatility. The results from in vitro experiments show, that polypyrrole enhanced the biocompatibility of the fibers. These fibers were further used for the preparation of the novel composite spinal cord bridges, which were tested in vitro and in vivo. The results from in vitro experiments show that the oriented fibers support the guidance of neurite outgrowth and narrow the axonal spread which is more focused around the fibers. This phenomenon is even more pronounced, if the fibers are coated with polypyrrole. The new spinal cord bridges were successfully implanted into mice' spinal cord for in vivo experiments. The results suggest the non-immunogenicity of the fibrous bridge samples. Moreover, the results show the activation of the pro-healing immune response in the both fibrous bridges. Also, the bridges with PCL fibers show higher axon infiltration compared to control. About 20 % of these axons are myelinated, 75 % of this myelin is derived from the Schwann cells. On the other hand, the axonal infiltration into the bridges with PPy-coated fibers is lower compared to bridges with PCL fibers or compared to control. Nevertheless, the obtained results show, that the oriented fibers enhance the axon infiltration into the spinal cord bridges and that the combination of the currently available approaches with new functionalization methods will be the method of choice for neural tissue engineering.
Materials based on orientated fibers have great potential for use in tissue engineering for tissues, where the arrangement of extracellular matrix is fundamental for tissue functionality. The drawing method is extremely suitable method for such applications. It is based on mechanical pulling of a polymer solution out of its base droplet, resulting in a single solidified fiber of determined geometrical characteristics. A new machine designed for lab scale drawing was invented enabling a repeatable quality of drawing conditions. The results demonstrate that by changing the speed of drawing and polymer solution concentration it is possible to influence and define the fiber diameter and its distribution. From the in vitro experiments, it is evident that the aligned fibers guide the cell growth in the direction of the fibers. Moreover, the prepared fibers were functionalized with polypyrrole as an example of their versatility. The results from in vitro experiments show, that polypyrrole enhanced the biocompatibility of the fibers. These fibers were further used for the preparation of the novel composite spinal cord bridges, which were tested in vitro and in vivo. The results from in vitro experiments show that the oriented fibers support the guidance of neurite outgrowth and narrow the axonal spread which is more focused around the fibers. This phenomenon is even more pronounced, if the fibers are coated with polypyrrole. The new spinal cord bridges were successfully implanted into mice' spinal cord for in vivo experiments. The results suggest the non-immunogenicity of the fibrous bridge samples. Moreover, the results show the activation of the pro-healing immune response in the both fibrous bridges. Also, the bridges with PCL fibers show higher axon infiltration compared to control. About 20 % of these axons are myelinated, 75 % of this myelin is derived from the Schwann cells. On the other hand, the axonal infiltration into the bridges with PPy-coated fibers is lower compared to bridges with PCL fibers or compared to control. Nevertheless, the obtained results show, that the oriented fibers enhance the axon infiltration into the spinal cord bridges and that the combination of the currently available approaches with new functionalization methods will be the method of choice for neural tissue engineering.
Description
Subject(s)
drawing, vlákna, tkáňové inženýrství nervové tkáně, mícha, in vitro, in vivo, drawing, fibers, neural tissue engineering, spinal cord, in vitro, in vivo