(75g) Enhancement of Cell Adhesion and Proliferation Through Surface Roughness Modification in CHO Cell Cultures in PMMA-PDMS Micro-Devices

Recently, the production of therapeutic proteins, particularly monoclonal antibodies, has grown significantly in the biopharmaceutical market. Chinese Hamster Ovary cells (CHO cells) are considered to be the standard mammalian cell host for the production of recombinant proteins. At the lab scale, this cell line is usually grown in bioreactors and Erlenmeyer flasks, where the culture medium has to be changed periodically. Culture of CHO cells in micro-devices could be a cost-effective strategy for screening and eventually commercial production of therapeutic proteins.

We document the continuous perfusion culture of a normally non-adherent cell line, CHO C8F4-A2, producer of a monoclonal antibody (mAb), in PMMA-PDMS micro-devices. Cell morphology, cell production, and mAb productivity of CHO C8F4-A2 cells were evaluated in PMMA-PDMS micro-devices. Three different designs were analyzed: wave, zigzag, and spherical. Surface Micro-devices surfaces were textured with 15 µm diameter pores. A textured surface was key to promote cell anchorage, since a non-adherent cell line was employed.  Cell adhesion, cell proliferation, and mAb production over time were evaluated under different operative conditions: (a) two different flow rates (0.1 µl min^-1 or 3 µl min^-1), and (b) with or without fibronectin coating in the micro-device surface. Computational Fluid Dynamics (CFD) was used to characterize the velocity field within the different micro-device designs.

For cell production and mAb productivity, the best results were achieved when applying fibronectin coating at low flow rate. In the absence of fibronectin coating, a considerable amount of cells were detached from surface during perfusion operation. Remarkably, under the best set of operative conditions, mAb productivity was comparable to that measured in stirred tank suspended culture (1.34 mg L^-1 h^-1). Results demonstrated that non-adherent cell lines can be successfully culture on textured surfaces coated with fibronectin under a continuous perfusion system. Our findings suggest that continuous perfusion systems with micro-devices can be used for the production of high added value biopharmaceuticals, as well as for screening purposes.