Large-Scale Cell Production Based on GMP-Grade Dissolvable Porous Microcarriers

Researchers in the cell and gene therapy (CGT) industry have long faced a formidable challenge in the efficient and large-scale expansion of cells. To address the primary shortcomings of the two-dimensional (2D) planar culturing system, we innovatively developed an automated closed industrial scale cell production (ACISCP) platform based on a GMP-grade, dissolvable, and porous microcarrier for the 3D culture of adherent cells, including human mesenchymal stem/stromal cells (hMSCs), HEK293T cells, and Vero cells. To achieve large-scale expansion, a two-stage expansion was conducted with 5 L and 15 L stirred-tank bioreactors to yield 1.1 x 1010 hMSCs with an overall 128-fold expansion within 9 days. The cells were harvested by completely dissolving the microcarriers, concentrated, washed and formulated with a continuous-flow centrifuge-based cell processing system, and then aliquoted with a cell filling system. Compared with 2D planar culture, there are no significant differences in the quality of hMSCs harvested from 3D culture. We have also applied these dissolvable porous microcarriers to other popular cell types in the CGT sector; specifically, HEK293T cells and Vero cells have been cultivated to peak cell densities of 1.68 x 107 cells/mL and 1.08 x 107 cells/mL, respectively. This study provides a protocol for using a bioprocess engineering platform harnessing the characteristics of GMP-grade dissolvable microcarriers and advanced closed equipment to achieve the industrial-scale manufacturing of adherent cells.