A new computer-controlled air-liquid interface cultivation system for the generation of differentiated cell cultures of the airway epithelium

The increased application of in vitro systems in pharmacology and toxicology requires cell culture systems that facilitate the cultivation process and ensure stable, reproducible and controllable cultivation conditions. Up to now, some devices have been developed for the cultivation of cells under submersed conditions. However, systems meeting the requirements of an air-liquid interface (ALI) cultivation for the special needs of bronchial epithelial cells for example are still lacking. In order to obtain in vivo like organization and differentiation of these cells they need to be cultivated under ALI conditions on microporous membranes in direct contact with the environmental atmosphere. For this purpose, a Long-Term-Cultivation system was developed (CULTEX® LTC-C system) for the computer-controlled cultivation of such cells. The transwell inserts are placed in an incubator module (24 inserts), which can be adjusted for the medium level (ultrasonic pulse-echosensor), time and volume-dependent medium exchange, and frequency for mixing the medium with a rotating disc for homogeneous distribution of medium and secretion components. Normal primary freshly isolated bronchial epithelial cells were cultivated for up to 38 days to show the efficiency of such a cultivation procedure for generating 3D cultures exhibiting in vivo-like pseudostratified organization of the cells as well as differentiation characteristics like mucus-producing and cilia-forming cells.