Cell-microcarrier adhesion to gas-liquid interfaces and foam

Area of Science:

• Biotechnology
• Cell Culture Engineering
• Bioprocess Engineering

Background:

• Microcarrier cultures are widely used for cell expansion in bioprocessing.
• Gas sparging is common in bioreactors but can cause cell damage.
• Understanding microcarrier-bubble interactions is crucial for optimizing cell culture conditions.

Purpose of the Study:

• To investigate the interaction between microcarriers (with and without cells) and gas bubbles.
• To evaluate protective additives for preventing microcarrier adhesion to bubbles and foam entrapment.
• To assess the impact of bubble rupture on cells attached to microcarriers.

Main Methods:

• Qualitative microscopic observation of microcarrier-bubble interactions.
• Quantitative measurement of microcarrier entrapment in foam layers.
• Quantitative assessment of bubble rupture effects on attached cells.
• Evaluation of ten "protective additives" for surface tension modification and adhesion prevention.

Main Results:

• Microcarriers, with or without cells, readily adhere to gas-medium interfaces.
• Cells attached to microcarriers are not damaged by bubble ruptures, unlike suspended cells.
• One surfactant reduced foam entrapment but proved toxic to cells.
• No correlation was found between surface tension changes and prevention of microcarrier adhesion to interfaces.

Conclusions:

• Cell damage in microcarrier cultures during sparging is likely due to cells detaching from microcarriers as bubbles rise.
• Hydrodynamic drag forces may dislodge bubble-attached cells from microcarriers.
• Further strategies are needed to mitigate cell damage during gas sparging in microcarrier systems.