Computational fluid dynamics (CFD) was used to evaluate how impeller type and vertical arrangement influence mixing performance and hydrodynamic stress in a nominal 30,000 L stirred-tank bioreactor operated at a 20,000 L working volume. Eight configurations containing different combinations of pitched-blade and Smith turbine impellers were simulated in COMSOL Multiphysics (v6.2) using the standard k-ε turbulence model. Mixing time, flow patterns, shear stress, and energy dissipation rate (EDR) were compared, and mixing-time mesh sensitivity was assessed using three mesh resolutions. Configurations with more pitched-blade impellers generally produced stronger axial circulation, shorter mixing times, and higher volume-average shear stress and EDR. The all-pitched-blade configuration mixed fastest, whereas the all-Smith configuration mixed slowest. Local maximum shear stress and EDR depended more strongly on impeller arrangement, and not predicted by vessel-average behavior alone. Comparison with a 3,000 L small-scale vessel showed that matching the selected impeller configuration and power input per unit volume (P/V) did not provide hydrodynamic equivalence. These results highlight the importance of evaluating impeller type, placement, and vessel scale together when balancing mixing performance and hydrodynamic exposure.
Lentiviral vectors (LVVs) are broadly used in research and therapeutic development, yet substantial interlaboratory variability continues to hinder the comparison of vector quantity, potency, and impurity measurements, underscoring the need for standardized reference materials. To address this need, the Lentiviral Vector Reference Material (LVVRM) initiative was launched as a structured, multi‑phase effort, with earlier phases focused on large‑scale upstream production and downstream preparation of a GFP-encoding LVV. In the final phase of the LVVRM initiative described herein, bulk material produced during prior large‑scale manufacturing runs was thawed, pooled, subjected to sterile filtration, and dispensed into single‑use vials under controlled conditions designed to maintain stability and consistency. Each lot then underwent comprehensive quality control testing. Sterility, identity, purity, physical and functional titers, and safety attributes were assessed using established characterization frameworks appropriate for lentiviral vector reference materials. The resulting LVVRM (ATCC® VR-3382™) met quality standards and release criteria, providing a well‑characterized reagent suitable for assay calibration, method qualification, and longitudinal performance monitoring across laboratories.
M&As continue at a dizzying pace even while so many organizations are just trying to hang on. Apparently some of the biggest firms still have excess money or access to cheap money, and they would rather spend it acquiring than building or solidifying what they have. But if they have so much money, why are they laying so many people off? At a biotech business meeting I recently attended in DC, I kept hearing that “companies have a lot of money.” But when I followed-up on this point with a panelist, I was told that much of this money could not be used for operations. Apparently because of the off-shore location, or other locations where it’s hiding, it can only be used to buy stock...
As biologics continue to advance at a dizzying pace, I want to take this opportunity to outline what I see as the major successes, as well as the primary challenges facing the industry. First, the science of antibody production appears to be quite settled. Significant value can be gained by finding ways to limit production batches to volumes that can be accommodated by single-use bioreactor systems...
