Evaluation of single-use optical and electrochemical pH sensors in upstream bioprocessing

• Published in: Heliyon 2024-02, Vol.10 (3), p.e25512-e25512, Article e25512
• Main Authors: Fratz-Berilla, Erica J., Kohnhorst, Casey, Trunfio, Nicholas, Bush, Xin, Gyorgypal, Aron, Agarabi, Cyrus
• Format: Article
• Language: English
• Subjects: Biomanufacturing; Bioprocessing; Bioreactors; Chinese hamster ovary cells; CHO; Monoclonal antibodies; pH control; pH sensor; Process control; Single-use technology
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e25512

Culture pH is a critical process parameter during CHO cell bioreactor operations that is key for proper cell growth, protein production, and maintaining the critical quality attributes of a monoclonal antibody drug substance. The traditional means of measuring pH in bioreactors is with an electrochemical probe that can withstand and maintain accuracy through repeated sterilization cycles. An alternative technique for measuring pH is an optical sensor composed of a fluorescent dye that is sensitive to the hydrogen ion concentration. In this work we explore single-use electrochemical and single-use optical pH sensors in stirred-tank and rocking bioreactors, respectively, to understand how their overall performance compares to traditional electrochemical probes in benchtop glass stirred tank bioreactors. We found that the single-use optical pH sensors were generally less accurate than the electrochemical probes, especially in detecting large pH drifts from the setpoint. The single-use electrochemical probes were increasingly accurate as pH was increased from