FIG. 1.

Conventional static two-dimensional (2D) culture conditions (A) and dynamic three-dimensional (3D) perfusion tissue-density conditions (B). The smallest interwoven capillary membrane unit exhibiting the compartments II to IV is shown; interweaving allows scale-up by multiplication of these units. The cell aggregate size in the cell compartment I is limited by the space between the capillaries. Each capillary membrane compartment can be perfused separately (medium perfusion compartment II, medium perfusion compartment IV, and oxygenation compartment III), addressing the reduction of substance gradient distances between the capillary units and enhancing mass exchange. Color images available online at www.liebertonline.com/ten.