Cell-based shear stress sensor for bioprocessing.

Area of Science:

• Biotechnology and Bioprocessing
• Cell Culture Engineering
• Bioreactor Design and Optimization

Background:

• Shear stress in bioreactors significantly impacts mammalian cell health, growth, and fate, crucial for next-generation cell therapies.
• Existing methods like computational fluid dynamics modeling and PCR assays for shear stress assessment have limitations in complexity and practicality.
• A need exists for a rapid, straightforward method to quantify shear stress in various bioreactor conditions.

Purpose of the Study:

• To develop and validate a simple, cell-based sensor for measuring shear stress in bioreactors.
• To enable optimization of bioprocess parameters for improved cell growth and yield.
• To facilitate the design of bioreactor vessels with reduced shear stress profiles.

Main Methods:

• Engineered Chinese Hamster Ovary (CHO-DG44) cells with the early growth response-1 (EGR-1) stress-sensitive promoter controlling Green Fluorescent Protein (GFP) expression.
• Quantified GFP levels in stressed CHO cells using a cell analysis instrument over 24 hours.
• Characterized sensor performance with chemical and fluid shear stress, and tested in Ambr® 250 bioreactor vessels with varying designs.

Main Results:

• The engineered CHO cells exhibited increased GFP expression correlating with higher shear stress magnitude and exposure time.
• Sensor characterization confirmed its sensitivity and stability under different stress conditions.
• Successful application in Ambr® 250 bioreactors demonstrated the sensor's utility in assessing bioreactor-imposed shear stress.

Conclusions:

• The developed CHO cell-based shear stress sensor provides a simple and effective tool for assessing bioreactor conditions.
• This sensor can facilitate process optimization and the design of low-shear bioreactor systems for sensitive cell cultures.
• It offers a practical alternative to complex modeling or laborious assay methods for shear stress evaluation.