Robust on-line sampling and analysis during long-term perfusion cultivation of mammalian cells

•A novel platform has been developed to address the unmet need for robust automated on-line sampling and analysis of mammalian cell bioreactors.•This includes sterile sampling, sample preparation and transport to online analyzers, and communication with process automation systems.•Robust operation of the automated sampling and analysis platform has been demonstrated in a 102 day perfusion process.•This higher resolution data set generated by this system can help accelerate process development by intensifying decision making.•In a commercial facility, this advance can enable successful realization of PAT both as a diagnostic tool and for routine process monitoring.

In an attempt to support robust automated sampling and analysis of mammalian cell bioreactors, an integrated platform, BaychroMAT®, was developed which includes an innovative sterile sampling device, automated sample transport, a sample preparation module, online analyzers, and communication interfaces to process automation systems. The robustness of this platform was verified by applying it to a laboratory-scale perfusion bioreactor that was operated for over 100 days. Both manual and automated samples were collected over the course of the run and a comparison was made for cell density, viability, glucose, and lactate concentrations. The highest variability (14.4%) was seen for cell density estimates while those for viability, glucose, and lactate were 0.7, 12.9, and 8.2%, respectively. In addition, cell density set-point changes were made towards the end of the perfusion culture and the high frequency automated samples provided a higher resolution description of the dynamics of cell density change compared to less frequent manual sampling. Overall, our results indicate stable and robust operation of the BaychroMAT® platform in a long-term perfusion culture. This success should readily translate to shorter duration fed-batch cultures thereby enabling feed-back control based on real-time nutrient measurements.