Defense Date

10-26-2021

Graduation Date

Fall 12-17-2021

Availability

One-year Embargo

Submission Type

dissertation

Degree Name

PhD

Department

Pharmaceutics

School

School of Pharmacy

Committee Chair

Carl A. Anderson

Committee Member

James K. Drennen III

Committee Member

Wilson S. Meng

Committee Member

Alan W. Seadler

Committee Member

Stephanie A. Ketcham

Keywords

Capacitance Spectroscopy, Mammalian Cell Culture, Multivariate Data Analysis, Process Analytical Technology, Flow Cytometry, Cell Death

Abstract

Biologics, including the monoclonal antibody (mAb), has experienced rapid development in the last decade. However, the price of biologics is often prohibitively high because of the low process efficiency. Delaying the inevitable cell death improves the productivity of upstream bioprocessing, whose success relies on monitoring the cell death onset that indicates the timing for preventive actions.

This study proposes to develop a real-time monitoring model that quantifies the dying cell percentage in lab-scale bioreactors using capacitance spectroscopy. The capacitance spectroscopy contains cell death-related information due to various physical properties changes during the cell death process, e.g., cytoplasmic conductivity change. The partial least square (PLS) regression algorithm constructed the model between the normalized capacitance spectra and dying cell percentages measured by flow cytometry. Samples following an orthogonal calibration design were prepared to build an at-line model, which was then transferred to the in-line monitoring condition to achieve real-time monitoring. The global calibration method was applied during the calibration transfer process to alleviate the difference between the at-line and in-line monitoring conditions. Furthermore, orthogonalization preprocessed the capacitance spectra, improving the model performance and mitigating the undesired prediction fluctuation due to process operations. The resulted model had a low Root Mean Square Error of Prediction, suggesting a good prediction accuracy. Additionally, the trajectory described by the final model captured the cell death onset hours earlier than the traditional viability test, providing a time window for subsequent preventive actions.

Language

English

Additional Citations

Wu, S., Rish, A. J., Skomo, A., Zhao, Y., Drennen, J. K., & Anderson, C. A. (2021). Rapid serum‐free/suspension adaptation: Medium development using a definitive screening design for Chinese hamster ovary cells. Biotechnology Progress, e3154.

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