<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION"^^ . "Wound healing is a complex, multi-step process. To be able to comprehensively examine the role\r\nof hyaluronic acid (HA) on re-epithelialization it is crucial to isolate re-epithelialization as the process\r\nwhere keratinocytes migrate and proliferate from the other processes during wound healing. The effect\r\nof HA on re-epithelialization is controversially discussed in literature and comparability between\r\nindependent studies is hampered as applied HA concentrations, molecular weight (MW) of HA as well\r\nas cell systems, substrate nature (glass, plastic) and extracellular matrix (ECM) composition all differ\r\nfrom publication to publication. Therefore, in this thesis I comprehensively compared for the first time\r\nthe effect of apical presented HA of different MW (5, 60, 700 and 1800 kDA) and concentrations (5,\r\n50, 500, 1000 μg/mL) within the framework of re-epithelialization using a human keratinocyte cell line\r\n(HaCaT). I showed that HA hampers migration on collagen I-coated glass surfaces in a concentrationdependent\r\nmanner whereas in terms of proliferation HA has a pro-proliferative effect under conditions\r\nof low density on cell culture plastic.\r\nWith the aim to further reduce the complexity of the interplay of HA with other ECM molecules\r\nit is crucial to have a wound healing system comprising of a minimal number of components with the\r\npossibility to stepwise increase complexity. Following a bottom-up approach I employed bifunctionalized\r\nglass surfaces and altered their functional groups: Only HA and a second, integrinaddressing\r\nbinding ligand were presented on an otherwise passivated background. In order to address\r\ndifferent integrin-binding families I proved the established cRGD as well as a novel peptide, EPDIM to\r\nbe suited to mediate HaCaT cell adhesion and subsequent spreading. Additionally, I investigated\r\nwhether end-alkylated HA of 5, 10 and 60 kDA can be bound to azide-presenting surfaces via click\r\nchemistry. Surface saturation with HA was determined via QCM-D experiments and accessibility of\r\nsurface-bound 5 and 10 kDA HA by the hyaladherin aggrecan proved bioactivity of immobilized HA.\r\nSurfaces presenting HA without additional adhesive peptides did not mediate HaCaT cell adhesion. Cell\r\nadhesion and subsequent spreading was observed on bi-functionalized glass surfaces with cRGD or\r\nEPDIM as a binding ligand together with three different concentrations of immobilized HA.\r\nFurthermore, indirect immunofluorescence revealed a direct correlation between immobilized HA and\r\nthe degree of focal adhesion formation.\r\nIn order to mimic the dynamic changes in ECM composition during wound healing (e.g. when\r\nthe provisional matrix evolves into granulation tissue) I developed a two-stage wound model system. I\r\nshowed that formation of confluent monolayers on polycarbonate membranes was achieved within 24 h.\r\nBy cutting such HaCaT-cultivated membranes (2D epidermal models) a real wound site was introduced.\r\nCustomized molds enabled the mechanical fixation of membrane-cultivated HaCaTs on any desired\r\nsurface without the need of collagen I glue thus ensuring a clean and well-controllable ECM\r\nenvironment without unintentional insertion of collateral ECM molecules. I demonstrated that such\r\nvegetated membranes can be used to observe migrational activities of keratinocytes in time-lapse\r\nVI\r\nimaging on collagen I gels, collagen I-coated glass surfaces as well as on minimalistic, highly-defined\r\nECM models, where only one single binding motif is presented. Furthermore, migration was also\r\nmediated upon providing bi-functionalized glass surfaces where the binding ligands cRGD or EPDIM\r\nwere presented orthogonally with HA of varying concentration. In contrast to systems in which cells\r\nform a confluent layer on the same surface they migrate on after wounding, this novel two-stage ECM\r\nsystem ensures that the migration interface is not harmed by the wounding procedure and can be\r\nchemically different than the interface on which the cell monolayer has been cultivated.\r\nCombining the two-stage ECM model with bi-functionalized surfaces creates a two-stage ECM\r\nwound healing model, which can be applied in 2D cell culture as well as 3D tissue systems and has the\r\npotential to reveal HA’s signaling role in cooperation with other ECM molecules on re-epithelialization\r\nin future application."^^ . "2020" . . . . . . . "Franziska"^^ . "Dietrich"^^ . "Franziska Dietrich"^^ . . . . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (PDF)"^^ . . . "Thesis-Franziska Dietrich.pdf"^^ . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (Other)"^^ . . . . . . "preview.jpg"^^ . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (Other)"^^ . . . . . . "medium.jpg"^^ . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (Other)"^^ . . . . . . "small.jpg"^^ . . . "A SYSTEM TO SEGMENT\r\nTHE ROLE OF HYALURONIC ACID\r\nDURING RE-EPITHELIALIZATION (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #29012 \n\nA SYSTEM TO SEGMENT \nTHE ROLE OF HYALURONIC ACID \nDURING RE-EPITHELIALIZATION\n\n" . "text/html" . . . "570 Biowissenschaften, Biologie"@de . "570 Life sciences"@en . .