Inline monitoring of cell cultures with Raman spectroscopy

Importance of the Topic

Cell culture underpins the manufacture of vaccines, monoclonal antibodies and other therapeutic proteins. Monitoring the balance between glucose consumption and lactate production is essential to prevent acidification, maintain cell health and maximize product yield. Inline, reagent-free Raman spectroscopy offers noninvasive real-time insights into culture status without risking contamination or delay.

Objectives and Study Overview

This study demonstrates an inline Raman spectroscopy approach using the Metrohm 2060 Raman Analyzer to track glucose and lactate levels in a bioreactor. It aims to build accurate calibration models against standard reference assays and to deliver minute-by-minute process analytics, supporting tight control of metabolic pathways.

Methodology and Instrumentation

• In situ Raman measurements via a 785 nm laser coupled to an autoclavable immersion probe.
• 2060 Raman Analyzer hardware for spectral acquisition.
• IMPACT and Vision software for data processing and calibration against titration, ion chromatography or HPLC reference methods.
• Spectral sampling frequency set to one measurement per minute for continuous monitoring.

Main Results and Discussion

• Calibration covered glucose concentrations from 0.1 to 40 g/L and lactate from 0 to 5 g/L.
• Prediction performance: glucose bias −0.135 g/L and SEP 0.201 g/L; lactate bias −0.085 g/L and SEP 0.117 g/L.
• Real-time spectra allow prompt adjustments to maintain glycolytic balance and optimal pH, minimizing cellular stress.
• Inline analysis eliminates contamination risks and offline sampling errors, reflecting true process conditions.

Benefits and Practical Applications

• Early detection of process deviations and potential batch failures.
• Simultaneous measurement of multiple parameters with a single, reagent-free technique.
• Noncontact, nondestructive measurement aligns with process analytical technology frameworks.
• Low water interference and distinct Raman fingerprints enable robust analyte identification.

Future Trends and Applications

• Integration of advanced chemometrics and machine learning for enhanced prediction accuracy.
• Expansion to additional metabolites, nutrients and product quality attributes within a single probe.
• Coupling inline Raman data with digital twins and automated control strategies for continuous bioprocessing.
• Application in emerging areas such as cell therapy production and viral vector manufacturing.

Conclusion

Inline Raman spectroscopy with the 2060 Raman Analyzer provides reliable, real-time monitoring of key metabolic parameters in cell cultures. This approach enhances process control, reduces contamination risk and supports consistent high-quality biopharmaceutical production.

References

1. Sigma Aldrich. Cell Culture for Manufacturing. Application Note.
2. Sigma Aldrich. Glucose in Cell Culture. Technical Article.
3. Admin. The Circle of Lactate: How Cancer Cells Can Reuse Their Own Waste. Science in the News, 2018.
4. Li Z M; Fan Z L; Wang X Y; et al. Factors Affecting the Expression of Recombinant Protein and Improvement Strategies in Chinese Hamster Ovary Cells. Front Bioeng Biotechnol 2022;10:880155.