Inline monitoring of cell cultures with Raman spectroscopy

Importance of the Topic

Inline Raman spectroscopy offers a reagent-free, non-contact approach to monitor critical cell culture parameters in real time, ensuring optimal biopharmaceutical production processes by preventing contamination and improving data reliability.

Objectives and Study Overview

This application note demonstrates the use of the 2060 Raman Analyzer to track glucose consumption and lactate accumulation inside a bioreactor, comparing inline Raman measurements against conventional reference methods to establish robust calibration models.

Methodology and Instrumentation

Inline measurements were performed using a 785 nm laser with an autoclavable immersion probe connected to the 2060 Raman Analyzer. Spectral data were acquired every minute and processed with Metrohm’s Vision and IMPACT software to build calibration models correlating Raman spectra with reference values from titration and ion chromatography.

Used Instrumentation

• 2060 Raman Analyzer with high-throughput spectrometer and stable laser source
• Autoclavable immersion probe for inline deployment in the bioreactor
• Metrohm Vision and IMPACT software for spectral processing and calibration

Results and Discussion

Calibration models delivered accurate predictions across the operational ranges: glucose from 0.1 to 40 g/L and lactate from 0 to 5 g/L. Bias values were –0.1349 g/L for glucose and –0.0849 g/L for lactate, with standard error of prediction (SEP) of 0.2009 g/L and 0.1166 g/L, respectively. These figures demonstrate tight agreement with reference methods and stable inline performance.

Benefits and Practical Applications

• Real-time detection of process deviations and early identification of batch failures
• Simultaneous monitoring of multiple analytes from a single spectrum
• Reduced contamination risk by eliminating manual sampling
• Minimal interference from water, enhancing data quality in aqueous media

Future Trends and Applications

Advancements in inline Raman spectroscopy may include integration with automated process control systems, expanded analyte libraries via machine learning, and miniaturized probes for diverse bioprocess scales, further accelerating pharmaceutical development cycles and ensuring consistent product quality.

Conclusion

The inline 2060 Raman Analyzer enables non-destructive, reagent-free monitoring of glucose and lactate, delivering near real-time insights into cell culture health and supporting high-quality biopharmaceutical manufacturing.

References

• Cell Culture for Manufacturing, Sigma-Aldrich
• Glucose in Cell Culture, Sigma-Aldrich
• The Circle of Lactate: How Cancer Cells Can Reuse Their Own Waste, Science in the News, 2018
• Li ZM, Fan ZL, Wang XY, et al. Factors Affecting Recombinant Protein Expression in CHO Cells. Front. Bioeng. Biotechnol., 2022, 10, 880155.