Shear-Sensitive Pumping with Peristaltic Pumps

Factors Impacting Shear Sensitivity

Peristaltic pumps have become the gold standard for shear-sensitive pumping applications where damage to cells or agitation of a suspension or colloidal mixture may interfere with the science being performed. Shear sensitivity concerns are especially common in live cell circulation within a bioreactor or food and beverage suspensions in manufacturing applications. Inherently, peristaltic pump technology provides gentle pumping action at low speeds, especially when compared to other positive displacement pumps which use tightly machined gears or high-speed impellers to move liquids. However, when it comes to providing the maximum protection to sensitive fluids not all peristaltic pumps are designed equally.

Many methods are available to compare shear forces within pumps. In this case, hemolysis of blood cells was used to evaluate the sensitivity of several pump designs for live cell circulation. In vitro testing was completed using citrated bovine blood circulated through several peristaltic pump systems and settings to establish optimal conditions. All testing was completed in accordance with ASTM F756-13 (Standard Practice for Assessment of Hemolytic Properties of Materials) and FDA 21 CFR Part 58 (Good Laboratory Practice for Nonclinical Laboratory Studies) by an ANSI-ASQ National Accreditation Board (ANAB)- accredited laboratory.

The performance of each pump system was evaluated against its Average Hemolytic Index (a measure of the percentage of hemolysis of the blood cells) for 180 minutes.