Cell culture device system and methods of use thereof

A multi-step method of growing, culturing and/or modifying cells within a device comprising a primary container having a first base section, a first top section arranged substantially in parallel with the first base section and a first wall element arranged between the first top section and the first base section and defining a corresponding internal lumen of the first primary container, in which the first wall element of the primary container is compressible with respect to the first top and first base sections, and in which the primary container has at least one optionally sealable inlet, in which the first wall element of the primary container is composed of a flexible material and includes one or more folds;

• and wherein the device further comprises one or more auxiliary containers, wherein each auxiliary container in the one or more auxiliary containers couples with a respective inlet or outlet on the first top section of the primary container, wherein each auxiliary container in the one or more auxiliary containers is external to the primary container and in fluid communication with the primary container, and wherein the one or more auxiliary containers is located on the first top section of the primary container, the multi-step method comprising introducing a cell population of interest into the primary container and sequentially adding one or more reagents from one or more auxiliary containers into the primary container in order to effect the desired growth, culturing and/or modification of the cells.