How FlexiPro™ TFF Minimizes Shear Stress — Insights from VERDOT

In tangential flow filtration (TFF), product integrity is everything—especially for fragile biologics such as viral vectors, lipid nanoparticles (LNPs), and mRNA-based therapies. Because TFF requires repeated circulation of product through pumps, valves, and membranes, shear stress can pose a real risk to sensitive molecules over extended processing times.

To address this concern, VERDOT evaluated the shear impact of the FlexiPro™ TFF single-use system in a September 2024 study led by Lilou Saly (Polytech Clermont) and Sébastien Lefebvre (VERDOT).

A Worst-Case Test for Fragile Products

Rather than testing with actual viral vectors, the study used 100 nm liposomes as a worst-case model. Liposomes are more fragile than AAVs, lentiviruses, or typical LNPs, making them an ideal indicator of potential shear-induced damage.

The liposomes were circulated through the FlexiPro™ TFF system for five continuous hours, simulating real-world downstream processing. Depending on flow rate, the product passed through the system up to 850 times, far exceeding typical process conditions.

What Was Evaluated

The study examined product integrity across:

• Multiple flow rates (33%, 66%, and 100%)
• Transmembrane pressures (TMP) up to 1.4 bar
• Two single-use pump technologies
  (PSG Dover Quattroflow® and Levitronix® PuraLev®)
• Full operating range of the Low Flow Kit

Liposome integrity was monitored using particle size and polydispersity index (PDI) measured by two independent light-scattering instruments.

Key Results: No Detectable Degradation

Across all tested conditions. Even under the highest flow and TMP conditions—representing the most shear-intensive scenarios—the liposomes remained intact throughout the five-hour circulation period.

• No decrease in particle size
• No increase in PDI
• No evidence of liposome degradation

Why This Matters

These results demonstrate that FlexiPro™ TFF delivers exceptionally low shear stress, even under worst-case conditions. This makes the system well suited for both fragile and non-fragile therapeutics, including:

• AAV and lentiviral vectors
• Lipid nanoparticles (LNPs)
• mRNA vaccines
• Cell- and gene-therapy applications

Learn More

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Evaluation of Shear Stress on the FlexiPro™ TFF System