Browsing by Subject "Micropatterning"
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Item Open Access Contact guidance enhances the quality of a tissue engineered corneal stroma(John Wiley & Sons, Inc., 2008) Vrana, E.; Builles, N.; Hindie, M.; Damour O.; Aydınlı, Atilla; Hasirci, V.Corneal stroma is a very complex structure, composed of 200 lamellae of oriented collagen fibers. This highly complex nature of cornea is known to be important for its transparency and mechanical integrity. Thus, an artificial cornea design has to take into account this complex structure. In this study, behavior of human corneal keratocytes on collagen films patterned with parallel channels was investigated. Keratocytes proliferated well on films and reached confluency after 7 days in the incubation medium. Nearly all of the cells responded to the patterns and were aligned in contrast to the cells on unpatterned surfaces. Collagen type I and keratan sulfate secreted by keratocytes on patterned films appeared to be aligned in the direction of the patterns. The films showed an intermediate degradation over the course of a month. On the whole, transparency of the films increased with degradation and decreased by the presence of the cells. The decrease was, however, low and transparency level was maintained on the patterned films while on the unpatterned films a sharp decrease in transparency was followed by an improvement. This was due to the more organized distribution of cells and the oriented secretion of extracellular matrix molecules on patterned collagen films. Thus, these results suggest that application of contact guidance in cornea tissue engineering may facilitate the remodeling process, hence decrease the rehabilitation period.Item Open Access Selective adsorption of L1210 leukemia cells/human leukocytes on micropatterned surfaces prepared from polystyrene/polypropylene-polyethylene blends(Elsevier, 2014) Atalay, N.; Unal, Hilal Unal; Erbil, H. Y.; Tekinay, Ayse BegumThe objective of this study is to prepare polymeric surfaces which will adsorb L1210 leukemia cells selectively more than that of healthy human leukocytes in order to develop new treatment options for people with leukemia. Chemically heterogeneous and micropatterned surfaces were formed on round glass slides by dip coating with accompanying phase-separation process where only commercial polymers were used. Surface properties were determined by using optical microscopy, 3D profilometry, SEM and measuring contact angles. Polymer, solvent/nonsolvent types, blend composition and temperature were found to be effective in controlling the dimensions of surface microislands. MTT tests were applied for cell viability performance of these surfaces. Polystyrene/polyethylene-polypropylene blend surfaces were found to show considerable positive selectivity to L1210 leukemia cells where L1210/healthy leukocytes adsorption ratio approached to 9-fold in vitro. Effects of wettability, surface free energy, microisland size geometry on the adsorption performances of L1210/leukocytes pairs are discussed.