Epithelia act in the organism as biological barriers. All of them are exposed to different environments at the
luminal and basal side. To simulate such a tissue-specific situation Minusheet® gradient perfusion culture was developed.
For pharmaceutical research, biomaterial testing and tissue engineering epithelial cells are cultured on individually selected
supports (1). Growing epithelia are stabilized within a tissue carrier (2). Long term culture is performed in a gradient
perfusion container (3). To expose epithelia to a tissue-specific environment fresh media of different composition are
transported parallel to the luminal and basal compartment of the gradient container. During culture leakage, edge damage
and pressure differences have to be avoided. Harvest of intact epithelia is promoted by the use of biocompatible supports
and innovative equipment such as transport of oxygen-rich and gas bubble-free medium. Actual literature demonstrates
that gradient perfusion culture is an effective method to investigate barrier functions under realistic conditions. Examples
of application comprise renal epithelia, retina, blood-air barrier, blood-brain barrier including aspects of tissue-specific
development and regeneration.