Monitoring of Nutrients, Metabolites, IgG Titer, and Cell Densities in 10 L Bioreactors Using Raman Spectroscopy and...

Area of Science:

• Biotechnology
• Process Analytical Technology (PAT)
• Spectroscopy

Background:

• Chinese hamster ovary (CHO) cell metabolism is intricate, affected by nutrients and metabolites.
• Real-time monitoring is crucial for optimizing cell culture conditions and product quality.
• Raman spectroscopy offers non-invasive, in situ monitoring capabilities for bioprocesses.

Purpose of the Study:

• To evaluate Raman spectroscopy for real-time monitoring of key metabolic parameters in CHO cell cultures.
• To assess the accuracy of Raman spectroscopy in predicting immunoglobulin G (IgG) titer.
• To demonstrate the potential of Raman spectroscopy for enhancing bioprocess control and consistency.

Main Methods:

• Raman spectroscopy was applied to five 10 L-scale CHO cell cultures.
• Partial least squares (PLS) regression models were developed using data from four batches, including one with induced cell death.
• Models were validated against blind test sets to ensure robustness.

Main Results:

• PLS models demonstrated high predictive accuracy (R² > 0.9) for monitored parameters.
• Reliable predictions were achieved for glucose and IgG titer (RMSEP = 0.51 g/L and 0.12 g/L, respectively).
• Predictions for viable and total cell density were less accurate due to the lack of direct Raman signals.

Conclusions:

• Raman spectroscopy is a viable tool for real-time, in situ bioprocess monitoring, eliminating the need for manual sampling.
• Chemometric analysis, particularly PLS, improves model robustness for automated control systems.
• Raman spectroscopy facilitates continuous feedback regulation of critical nutrients, ensuring consistent critical quality attributes (CQAs) in biopharmaceutical manufacturing.