Efficient Manufacturing of Adherent Cells: Mesenchymal Stem Cells and Microcarriers in Alginate Tubes

A method is described for the culture of adherent cells to high densities in the protective environment of alginate tubes. Microcarriers (MCs) are co-extruded with 0.8 million cells/mL in submillimeter alginate tubes to create internal surfaces of ~100 cm2/mL. At 30% (v/v) MCs in the lumen, the final cell density was 79.5 million cells/mL. The cell viability was 94% and a 100-fold expansion was attained. The extrusion process is automated, which makes the extrusion process straightforward. Culturing cells in alginate tubes addresses three problems which plague their production in stirred tank reactors: (1) cells are shielded from shear stress, (2) uncontrolled cluster growth is prevented because cluster size is limited to the inner tube diameter, and (3) the micro-environment within the tubes affects cell fate and this micro-environment can be replicated independently of reactor size. Thus, this method allows scaling up to become significantly easier.