| CPC C12M 27/02 (2013.01) [B01F 27/054 (2022.01); B01F 27/0727 (2022.01); B01F 27/11251 (2022.01); B01F 27/2124 (2022.01); B01F 35/513 (2022.01); C12M 23/26 (2013.01); B01F 2101/44 (2022.01)] | 12 Claims | 

| 
               1. A method of culturing cells using a collapsible cell culture vessel, comprising: 
            providing a flexible portion containing nutrients that support in vitro cultivation of cells; 
                providing a mixing element disposed within the flexible portion to mix a cell culture, wherein the mixing element comprises a foldable sheet, the foldable sheet comprising a protrusion configured to create vigorous flow of a fluid within the flexible portion; 
                inflating the flexible portion; and 
                unfolding the foldable sheet. 
               |