Defective flow space limits the scaling up of turbulence bioreactors for platelet generation

Abstract

To complement donor-dependent platelets supplies, we previously developed an ex vivo manufacturing system using induced pluripotent stem cell (iPSC)-derived expandable immortalized megakaryocyte progenitor cell lines (imMKCLs), and a turbulent flow bioreactor to generate iPSC-derived platelets products (iPSC-PLTs). However, the tank size of the bioreactor was limited to 10 L. Here we examined the feasibility of scaling up to 50 L with reciprocal motion by two impellers. Under optimized turbulence parameters corresponding to 10 L bioreactor, 50 L bioreactor elicited iPSC-PLTs with intact in vivo hemostatic function but with less production efficiency. This insufficiency was caused by increased defective turbulent flow space. A computer simulation proposed that designing 50 L turbulent flow bioreactor with three impellers or a new bioreactor with a modified rotating impeller and unique structure reduces this space. These findings indicate that large-scale iPSC-PLTs manufacturing from cultured imMKCLs requires optimization of the tank structure in addition to optimal turbulent energy and shear stress.