(567i) Adherent Cell Culture for Nonadherent Cells in PDMS Microdevices

Chinese Hamster Ovary cells (CHO cells) are the most frequently used mammalian cells for the production of biopharmaceuticals. We document the culture of a non-adherent CHO DG44 cell line, producer of a monoclonal antibody (mAb), in PDMS micro-devices. At the lab scale, CHO DG44 cells are normally grown in T-flasks. This culture strategy requires a high amount of medium, which needs to be changed periodically. Anchorage dependant culture in micro-devices can minimize media requirements, and make possible continuous perfusion culture at a small scale for screening applications. Four different strategies to achieve cell adhesion on PDMS surfaces were tested: (1) suspension in an adherent cell medium (CHO III A); (2) suspension in CHO III A medium supplemented with 10% of fetal bovine serum; (3) suspension in CHO III A medium added with a factor attachment applied to the PDMS surface; and (4) suspension in CHO III A medium supplemented with 10% of fetal bovine serum and factor attachment applied to the PDMS surface. Cell attachment, cell density, and mAb productivity were evaluated for different flow rate regimes and attachment strategies. Results showed that strategies (2) and (4), yield the highest amount of cells adhered to the wall surface. Cells tolerated continuous flow rates up to 5 µL/min without significant detachment or decrease in productivity. Since option (4) required the use of fetal bovine serum, which is not recommended for biopharmaceutical commercial production, option (2) is suggested as the best strategy for adhesion of CHO DG44 cells on PDMS surfaces.