A concept for continuous virus manufacture using a moving bed bioreactor: Growth of MDCK cells to confluence on paper as a model support

Abstract A moving-bed bioreactor (MBB) could intensify growth of adherent mammalian cells for viral vaccines. A continuously fed sterile paper passing through a thin liquid layer as a flexible cell substrate is a new concept for bioprocess intensification (BPI). Paper could enable cell expansion with reduced footprint and reduced media consumption as the first stage of a 2-stage growth + infection continuous process. This study focused only on cell growth (stage 1). We report a simple 32 mm paper disc method to evaluate growth of adherent Madin Darby canine kidney cells (MDCK CCL-34) adapted to 5% FBS to confluence on unmodified papers to screen substrates. Bibulous paper was found to be the best substrate for proliferation of MDCK. An MBB process was simulated using paper discs to test growth to confluence (stage 1). Growth was characterized using staining, image analysis; confocal microscopy. Cells grew on the surface of bibulous paper to a confluence of >90% in 192 h. Extending this concept by stabilizing MDCK on paper (end of stage 1) by engineering cells to survive freezing or lyoprotection would enable live cells to be shipped as modules to multiple manufacturing sites for infection resulting in rapid, reproducible viral vaccine manufacture.