Viable cell density on-line auto-control in perfusion cell culture aided by in-situ Raman spectroscopy

In-situ Raman spectroscopy emerged as an innovative tool and robust technique to monitor and control the mammalian cell culture process in real-time. Here, the state-of-the-art perfusion cell culture and Raman integrated system was set up where metabolites on-line monitoring and viable cell density on-line auto-control were achieved, which have profound effects on in-process product quality control. Most key metabolites, i.e. glucose, lactate, osmolality, and IgG could be predicted accurately with root mean square error of prediction (RMSEP) of 0.71 g/L, 0.24 g/L, 4.73 mosmo/kg and 147.48 mg/L respectively utilizing the model calibrated from just one batch. We also demonstrated that 2nd derivative preprocessing on the Raman spectra could lead to better performance in the VCD prediction than 1st derivative in the perfusion cell culture, which were also proved statistically in Hotelling's T-2 profile, then a feasible auto-control strategy for VCD in perfusion mammalian cell culture was achieved where the on-line and off-line VCD were maintained around the target VCD of 50 x 10(6) viable cells/mL, i.e. 50.98 +/- 1.76 viable cells/mL and 50.67 +/- 2.67 viable cells/mL respectively for 11 days. Our findings proved that statistical verified model with high accuracy and regular P.I.D algorithm were adequate to fulfill auto-bleeding using Raman in perfusion cell culture. Those results help to deepen our understanding of perfusion cell culture process control, broaden the application for Raman spectroscopy in the continuous manufacturing, and offer a powerful control strategy which might benefit the shaping of the product quality.

Automated summary

The study established a perfusion cell culture and Raman integrated system for real-time monitoring of metabolites and auto-control of viable cell density, maintaining online and offline VCD around the target value. This control strategy offers strong support for product quality control.