Gelatin is a natural polymer used in pharmaceutical and medical applications, especially in the production of biocompatible and biodegradable wound dressings and drug delivery systems. Gelatin granules hydrate, swell and solubilize in water, and rapidly degrade in vivo. The durability of these materials could, however, be prolonged by cross-linking by aldehydes, carbodiimides, and aldose sugars, but the biocompatibility of collagenous biomaterials is profoundly influenced by the nature and extent of cross-linking. In this study, gelatin sponges were prepared by using various cross-linkers such as glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDAC), and D-fructose. The effects of the type and the amount of cross-linker on thermal and mechanical properties, stability, and cytotoxicity were investigated. The mechanical analysis data showed that an increase in the amount of GA in the sponge structures caused a slight increase in the modulus of elasticity but had almost no effect on the tensile strength. Increase in the EDAC concentration produced a maximum in the modulus of elasticity and tensile strength values. The stability of the sponges and the time required for complete degradation in aqueous media increased in parallel with the cross-linker content. In vitro studies carried out with fibroblast cells demonstrated a higher cell viability for the samples cross-linked with low concentrations of GA than for those cross-linked with EDAC.

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Objective: For in vitro tissue engineering in urology, stem cells are commonly isolated from tissue specimens obtained during open or endoscopic surgery. Within the context of the present study our aim was to isolate cells from human urine by an alternative and safe technique rather than using the indicated method. Material and methods:After human urine samples had been collected from young and healthy donors via urethral catheterization, cells were precipitated by centrifugation and cultured. Following this isolation procedure, cells were characterized by immunocytochemical method using specific antibodies.Results: When these cells were characterized by immunocytochemical methods using specific antibodies some of them were positive for mesenchymal stem cell marker CD90 while the others were labelled with urothelial marker cytokeratin 7. When all these results were taken into consideration, urothelial cells together with stem cells were observed in the urine-derived cell population. Conclusion:According to the results obtained from this study human urine may be preferred as an alternative stem cell and urothelial cell source in that this method is and easily reproducible non-invasive method.

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