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End date: 2019 × Subject: cell culture ×

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    Tailoring three-dimensional architectures by rolled-up nanotechnology for mimicking microvasculatures
    (Cambridge : Royal Society of Chemistry, 2015) Arayanarakool, Rerngchai; Meyer, Anne K.; Helbig, Linda; Sanchez, Samuel; Schmidt, Oliver G.
    Artificial microvasculature, particularly as part of the blood–brain barrier, has a high benefit for pharmacological drug discovery and uptake regulation. We demonstrate the fabrication of tubular structures with patterns of holes, which are capable of mimicking microvasculatures. By using photolithography, the dimensions of the cylindrical scaffolds can be precisely tuned as well as the alignment and size of holes. Overlapping holes can be tailored to create diverse three-dimensional configurations, for example, periodic nanoscaled apertures. The porous tubes, which can be made from diverse materials for differential functionalization, are biocompatible and can be modified to be biodegradable in the culture medium. As a proof of concept, endothelial cells (ECs) as well as astrocytes were cultured on these scaffolds. They form monolayers along the scaffolds, are guided by the array of holes and express tight junctions. Nanoscaled filaments of cells on these scaffolds were visualized by scanning electron microscopy (SEM). This work provides the basic concept mainly for an in vitro model of microvasculature which could also be possibly implanted in vivo due to its biodegradability.
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    Synthesis of biphasic Al/Al2O3 nanostructures under microgravity and laser structuring on Al/Al2O3 surfaces for selective cell guidance
    (Saarbrücken : Universität des Saarlandes, 2013) Lee, Juseok
    The first part of this thesis is dealing with gravity effect on the synthesis of biphasic core/shell Al/Al2O3 composites. By chemical vapor deposition of the precursor [tBuOAlH2]2 at 400°C, only spherical nanoparticles were observed on the substrate surface. The formation of nanowires was observed at 600°C. It is a good agreement with our previous results on earth condition and there is no gravity impact on the chemical reaction. At increased gravity levels, the nanoparticles formed large clusters and the nanowires showed bundle formation while the nanowires at microgravity have predominantly linear structures. It is proposed that the chaotic nature of nanowires and cluster formation of nanoparticles were caused by a dominance of gravity over the thermal creep. In the second part the use of Al/Al2O3 nanowire layers for bio applications is considered. Contact cell guidance and alignment were studied to understand how cells recognize and respond to certain surface patterns. Linear micro channels were created on Al/Al2O3 layer by direct laser writing and laser interference patterning. Although surface topography was altered, the surface chemistry was always identical (Al2O3) due to the unique core/shell nature of Al/Al2O3 nanowires. Human osteoblast, normal human dermal fibroblast and neuronal cells were cultured and investigated. The results indicate that different cell types show diverse responses to the topography independent from the surface chemistry of the material.