Using CellSeed's UpCell® temperature-responsive cell cultureware, cells that have been grown to confluency can be detached from the surface of the cultureware as a single sheet. These sheet-like clusters of cells are called "cell sheets". With conventional techniques, cultured cell clusters were disassociated into their constituent cells when harvested because a proteolytic enzyme was used to detach them from the cultureware surface. To address this problem, Professor Teruo Okano of Tokyo Women's Medical University (and a director of CellSeed) developed temperature-responsive cell cultureware, an innovative concept that is entirely different from the existing technology, a method for culturing cells based on this technology, and pioneered the new field of cell sheet engineering. CellSeed has aggressively tackled the commercialization of this labware.