The increased use of antibodies for human therapy has driven rational approaches to accelerate bioprocess development in producing cost effective and highly productive antibodies. The potential of microwell based systems and miniature bioreactors (MBR) to mimic the scalability and operations of conventional bench reactors are seen as an alternative. This study has investigated the microtitre plate (MTP), microMatrix and MBR (HEL-BioXplore) as scale-down mimic for rapid and accurate reproduction of Chinese hamster ovary (CHO) cell growth and product yields in bench scale stirred tank reactors. A microtitre plate with sandwich lid CR1524a (for slow growing animal cells) was found to be suitable for CHO cell cultivation. An evaluation of feeding approaches in MTP showed that bolus addition resulted in 9.19 x 106 cell mL-1 and 38 % higher IgG titres compared to addition of FeedBeads. In order to enable scale translation, the engineering parameters for the MBR were characterised with regard to mixing time, volumetric oxygen transfer coefficient and power input. The MBR system was fitted with either direct driven impeller or magnetically driven impeller with singular hole impeller or horseshoe sparger. The combination of the direct driven impeller and horseshoe type sparger with bolus addition was selected as the best configuration and produced 8.89 x 106 cell mL-1 and 0.84 gL-1 IgG titres. Additionally, a prototype micro-Matrix system was characterised for its performance in a cell culture process. The micro-Matrix with controlled aeration and continuous feeding supported a cell concentration of 8.67 x 106 cell mL-1 and viability >90 % after 264 hours. Furthermore, scale translations of the studied systems were evaluated at the matched mixing time of 6 s with conventional lab scale 5L stirred tank reactors (STR). The scale-up studies demonstrated that the miniature systems were able to mimic the performance of the conventional bench reactors. Results from the scale-up studies between the MTP, MBR and STR with bolus feeding addition showed a comparable viable cell concentration of 9.30 x 106 cell mL-1 , 9.56 x 106 cell mL-1 and 10.04 x 106 cell mL-1 and IgG titres of 0.92, 0.69 and 0.83 gL-1 respectively. Whereas, scale translation studies between micro-Matrix and MBR with continuous feeding gave equivalent viable cell concentration with 11.1 x 106 cell mL-1 and 9.76 x 106 cell mL-1 and IgG titres of 0.50 gL-1 and 0.64 gL-1 respectively. Overall, the miniature bioreactors evaluated have the potential for cell screening and optimisation studies which could generate early data for bioprocess development.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:763065 |
| Date | January 2015 |
| Creators | Sani, M. H. B. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1473531/ |
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