Shear Stress

Shear Stress describes mechanical forces generated when fluid layers move at different speeds, creating frictional stress that can affect cells, proteins, and formulations during manufacturing operations. In bioprocessing, shear arises from agitation, pumping, filtration, and mixing, and can influence cell viability and product quality.

The biopharmaceutical industry manages shear stress carefully during upstream cell culture and downstream purification. Excessive shear can damage fragile mammalian cells, reduce productivity, and increase release of host cell impurities, while protein therapeutics may undergo denaturation or aggregation under harsh shear conditions. Process development teams optimise impeller design, agitation rates, tubing dimensions, and flow paths to balance oxygen transfer and mixing efficiency against shear-related risks. Computational fluid dynamics modelling supports bioreactor design and scale-up by predicting shear distribution across vessel sizes. Single-use systems require careful evaluation of pump and connector designs to minimise protein damage during processing. As intensified processes increase throughput demands and shear sensitivity of complex biologics must be managed, shear stress characterisation remains essential for robust bioprocess design.