The present invention provides for a bioreactor system (3, 4) that is suited for one time use. The bioreactor system (3, 4) comprises a first bioreactor vessel (1), a second bioreactor vessel (20), a tissue retainer (35), and a cap (40). Advantageously, the bioreactor system (3, 4) of the present invention provides a sterile environment that is maintained over the course of cell seeding applications.