Recent advances in miniaturized cell culture systems have facilitated the screening of media additives on productivity and protein quality attributes of mammalian cell cultures. However, intracellular components are not routinely measured due to the limited throughput of available analytical techniques. In this work, time profiling of intracellular nucleotides and nucleotide sugars of CHO-S cell fed-batch processes in a micro-scale bioreactor system was carried out using a recently developed high-throughput method based on matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF-MS). Supplementation of various media additives significantly altered the intracellular nucleotides and nucleotide sugars that are inextricably linked to the process of glycosylation. The results revealed that UDP-Gal synthesis appeared to be particularly limiting whereas the impact of elevated UDP-GlcNAc and GDP-Fuc levels on the final glycosylation patterns was only marginally important. In contrast, manganese and asparagine supplementation altered the glycan profiles without affecting intracellular components. The combination of miniaturized cell cultures and high-throughput analytical techniques serves therefore as a useful tool for future quality driven media optimization studies.

Department of Chemical Engineering University of Chemistry and Technology Technicka 5 166 28 Prague Czech Republic

Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich CH 8093 Zurich Switzerland

Laboratory of Organic Chemistry Department of Chemistry and Applied Biosciences ETH Zurich CH 8093 Zurich Switzerland

Merck Serono SA Corsier sur Vevey Biotech Process Sciences ZI B CH 1809 Fenil sur Corsier Switzerland

References provided by Crossref.org