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Mikrooptische Systeme erhalten in unserer Zeit eine immer wichtigere Bedeutung. Es müssen dafür die bisherigen Herstellungsmethoden überdacht und nach neuen Prinzipien geforscht werden. Mikrolinsen werden in Detektoren, Glasfaserkupplungen oder auch in der Sensortechnik eingesetzt. In dieser Arbeit wird die prinzipielle Machbarkeit geprüft, Mikrolinsen mit Hilfe eines Tintenstrahl- und Tampondruck- Prozesses herzustellen, indem ein hybrid-organisch-anorganisches Sol auf einem Glassubstrat abgesetzt wird. Viskosität, Lösungsmittelverdunstung, Benetzungseigenschaften und Substrattemperaturen spielen eine große Rolle in der reproduzierbaren Herstellung von Mikrolinsen. Beim Tintenstrahl-Verfahren ist die Herstellung von Einzellinsen und 2D Linsenfeldern aus Solen mit niedrigen Viskositäten möglich. Die Strukturen wurden mittels Profilometrie und Rasterkraftmikroskopie bestimmt. Die optischen Eigenschaften wurden mittels Mikroskopie und spektroskopischen Methoden ermittelt. Die Linsen besitzen Durchmesser von 70 bis 2000 μm, Brennweiten von 165 μm bis 15,8 mm. Das Kapillar (GLT)- Dosiersystem oder das Tampondruck- Verfahren erlaubt z.B. Zylinderlinsen oder größere Linsendimensionen herzustellen.
The microvascular endothelium of the gut barrier plays a crucial role during inflammation in inflammatory bowel disease. We have modified a commonly used intestinal cell model based on the Caco-2 cells by adding microvascular endothelial cells (ISO-HAS-1). Transwell filters were used with intestinal barrier-forming Caco-2 cells on top and the ISO-HAS-1 on the bottom of the filter. The goal was to determine whether this coculture mimics the in vivo situation more closely, and whether the model is suitable to evaluate interactions of, for example, prospective nanosized drug vehicles or contrast agents with this coculture in a physiological and inflamed state as it would occur in inflammatory bowel disease. We monitored the inflammatory responsiveness of the cells (release of IL-8, soluble intercellular adhesion molecule 1, and soluble E-selectin) after exposure to inflammatory stimuli (lipopolysaccharide, TNF- α, INF-γ, IL1-β) and a nanoparticle (Ba/Gd: coprecipitated BaSO4 and Gd(OH)3), generally used as contrast agents. The barrier integrity of the coculture was evaluated via the determination of transepithelial electrical resistance and the apparent permeability coefficient (Papp) of NaFITC. The behavior of the coculture Caco-1/ISO-HAS-1 was compared to the respective monocultures Caco-2 and ISO-HAS-1. Based on transepithelial electrical resistance, the epithelial barrier integrity of the coculture remained stable during incubation with all stimuli, whereas the Papp decreased after exposure to the cytokine mixture (TNF-α, INF-γ, IL1-β, and Ba/Gd). Both the endothelial and epithelial monocultures showed a high inflammatory response in both the upper and lower transwell-compartments. However, in the coculture, inflammatory mediators were only detected on the epithelial side and not on the endothelial side. Thus in the coculture, based on the Papp, the epithelial barrier appears to prevent a potential inflammatory overreaction in the underlying endothelial cells. In summary, this coculture model exhibits in vivo-like features, which cannot be observed in conventional monocultures, making the former more suitable to study interactions with external stimuli.
