Novel micro‐bioreactor high throughput technology for cell culture process development: Reproducibility and scalability assessment of fed‐batch CHO cultures

Abstract

With increasing timeline pressures to get therapeutic and vaccine candidates into the clinic, resource intensive approaches such as the use of shake flasks and bench-top bioreactors may limit the design space for experimentation to yield highly productive processes. The need to conduct large numbers of experiments has resulted in the use of miniaturized high-throughput (HT) technology for process development. One such high-throughput system is the SimCell platform, a robotically driven, cell culture bioreactor system developed by BioProcessors Corp. This study describes the use of the SimCell micro-bioreactor technology for fed-batch cultivation of a GS-CHO transfectant expressing a model IgG4 monoclonal antibody. Cultivations were conducted in gas-permeable chambers based on a micro-fluidic design, with six micro-bioreactors (MBs) per micro-bioreactor array (MBA). Online, non-invasive measurement of total cell density, pH and dissolved oxygen (DO) was performed. One hundred fourteen parallel MBs (19 MBAs) were employed to examine process reproducibility and scalability at shake flask, 3- and 100-L bioreactor scales. The results of the study demonstrate that the SimCell platform operated under fed-batch conditions could support viable cell concentrations up to least 12 x 10(6) cells/mL. In addition, both intra-MB (MB to MB) as well as intra-MBA (MBA to MBA) culture performance was found to be highly reproducible. The intra-MB and -MBA variability was calculated for each measurement as the coefficient of variation defined as CV (%) = (standard deviation/mean) x 100. The % CV values for most intra-MB and intra-MBA measurements were generally under 10% and the intra-MBA values were slightly lower than those for intra-MB. Cell growth, process parameters, metabolic and protein titer profiles were also compared to those from shake flask, bench-top, and pilot scale bioreactor cultivations and found to be within +/-20% of the historical averages.

Assessment of AMBR<sup>TM</sup> as a model for high-throughput cell culture process development strategy

“…The typical cell inoculation density was 3.0 -5.0 × 10 5 cells/mL and the culture was routinely passaged three times per week. For MAb3 cell line the cultures were maintained and propagated as described in [9].…”

“…Recent literature have demonstrated availability of various designs of micro-scale reactors from a simpler standard plate with integrated sensors called Microtiter plate based bioreactors (MTB) [6][7][8][9][10][11][12] to more advanced cell culture systems such as the Stirred Mini Bioreactors (MBR) with control capabilities close to bench-top bioreactors for high throughput cell culture screening and optimization studies [13][14][15][16][17]. MBRs possess the advantage of being able to closely mirror the bench-scale bio-reactors in their monitoring and control capabilities and hence are considered as a preferred alternative vessel over shake flasks or MTBs for early stage process development.…”

Tailoring recombinant protein quality by rational media design

“…With respect to cell-line engineering, opting for media optimization considerably reduces development timelines and the complexity of product quality comparability considerations, which typically results from redevelopment of cell lines. High-throughput cell culture systems opened the door for testing many conditions simultaneously [266][267][268] . The technology developed for media optimization in 96-deepwell plates (96-DWP) fed-batch cultures 26,27,251 can also be applied for product quality modulation 25,64 .…”

Scale-down of CHO cell fed-batch cultures

“…Such systems can drastically decrease the time requirement and labor intensity on the sampling actions of mL-scale systems. Advanced online cell culture monitoring technologies are available, including online dielectric spectroscopy 246 and light scattering 191 , which can be used to measure viable cell density and viable cell volume, and online Raman spectroscopy 247 and infrared spectroscopy 248 , which can be used to monitor several culture metabolites and glycoprotein titer. Integration of these technologies into mL-scale bioreactors can reduce the liquid handling activities, solve the problem related to the small sample volume, and more importantly, increase the data throughput and resolution.…”

“…The mL-scale systems were originally designed for quick screening of clones, media, and culture parameters such as pH and temperature. In recent years, many studies 165,172,190,191 have shown that these mL-scale systems are quite representative for the bioreactors ranging from L-scale to kL-scale.…”