Capacitance spectroscopy enables real‐time monitoring of early cell death in mammalian cell culture. Issue 3 (22nd December 2022)

• Record Type: Journal Article
• Authors: Wu, Suyang; Ketcham, Stephanie A; Corredor, Claudia C.; Both, Douglas; Drennen, James K.; Anderson, Carl A.
• Is Part Of: Biotechnology journal. Volume 18:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-22
• Subjects: bioprocess engineering -- (BIO) capacitance spectroscopy -- cell Culture -- cell Death Monitoring -- CHO Cells -- industrial biotechnology -- process analytical technology (PAT); Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.202200231
• Languages: English
• ISSNs: 1860-6768

Abstract

Abstract: Background/Aims: Previous work developed a quantitative model using capacitance spectroscopy in an at‐line setup to predict the dying cell percentage measured from a flow cytometer. This work aimed to transfer the at‐line model to monitor lab‐scale bioreactors in real‐time, waiving the need for frequent sampling and enabling precise controls. Methods and Results: Due to the difference between the at‐line and in‐line capacitance probes, direct application of the at‐line model resulted in poor accuracy and high prediction bias. A new model with a variable range and offering similar spectral shape across all probes was first constructed, improving prediction accuracy. Moreover, the global calibration method included the variance of different probes and scales in the model, reducing prediction bias. External parameter orthogonalization, a preprocessing method, also mitigated the interference from feeding, which further improved model performance. The root‐mean‐square error of prediction of the final model was 6.56% (8.42% of the prediction range) with an R 2 of 92.4%. Conclusion: The culture evolution trajectory predicted by the in‐line model captured the cell death and alarmed cell death onset earlier than the trypan blue exclusion test. Additionally, the incorporation of at‐line spectra following orthogonal design into the calibration set was shown to generate calibration models that are more robust than the calibration models constructed using the in‐line spectra only. This is advantageous, as at‐line spectral collection is easier, faster, and more material‐sparing than in‐line spectra collection. Graphical Abstract and Lay Summary: A multivariate model monitoring early cell death was constructed by incorporating capacitance spectra, collected from a small at‐line device and in‐situ bioreactor data, into the calibration set. The model yielded accurate real‐time predictions when used in 5‐L bioreactors, compared to the offline reference method, flow cytometer. The prediction fluctuations due to process operation were mitigated using the external parameter orthogonalization.