CFD-aided design and hydrodynamic characterization of a single-use perfusion bioreactor for high density cell culture

To address the challenges of high-density animal cell culture, this study developed a high-density culture system comprising a single-use bioreactor (SUB) with a nominal volume of 500 mL and a pulsed tangential flow filtration (ITF) unit. The reactor can be configured with two layers of 35 mm diameter impellers-either double Elephant Ear (EE-EE) or Elephant Ear combined with Ribbon (EE-RB). The flow field characteristics were rigorously characterized through CFD simulations (60-240 rpm; 90-480 mL) validated by experimental data. Engineering analysis revealed the system's robust culture environment: [Formula: see text] values ranging from 2 to 15 h^-1 (60-180 rpm; 200-400 mL; 30-150 mL/min aeration), [Formula: see text] values from 0.1 to 10 W/m³, and mixing times between 1 and 10 s. Crucially, the system maintains a mild shear environment with an average shear strain rate (SSR) below 25 s^-1, fully within the physiological tolerance range for mammalian cells. This low-shear, high-mass-transfer design was validated through perfusion cultures of CHO and HEK293 cells. The system achieved exceptionally high cell densities of 8.32 × 10⁷ cells/mL and 1.17 × 10⁸ cells/mL, respectively, with cell viability consistently exceeding 90%, demonstrating its suitability for high-intensity biopharmaceutical production.