Application of bacterial-derived long cellulose nanofiber to suspension culture of mammalian cells as a shear protectant.

Nanofibrillated bacterial cellulose (NFBC) is a bio-compatible long-fiber nanocellulose produced by cellulose-synthesizing bacteria. It forms an entangled network structure in the suspension state, thereby imparting greater viscosity than conventional media additives. In this study, we examined its application as a shear protectant in the suspension culture of mammalian cells to mitigate hydrodynamic stress imposed on the cells. The media supplemented with hydroxypropyl cellulose-adsorbed NFBC (HP-NFBC) exhibited an increase in shear viscosity according to rheometric analysis, similar to FP003, a commercially available medium additive. Suspension culture of Chinese hamster ovary cells in HP-NFBC-containing media under a high stirring rate (120 rpm) demonstrated higher cell growth and lower cell death compared to those in the medium without additives and in FP003. A 0.10 (w/v)% concentration of HP-NFBC showed the highest viable cell number among the tested concentrations. Computational fluid dynamics simulation revealed a decrease in shear rate and flow velocity within the spinner flask owing to the addition of HP-NFBC or FP003. It is suggested that the decline of these parameters in high-viscosity media suppresses the hydrodynamic stress on cells. This study highlights the potential of HP-NFBC as a shear protectant in mammalian cell suspension culture.