Microfluidic-Printed Microcarrier for In Vitro Expansion of Adherent Stem Cells in 3D Culture Platform.

Microcarrier-based stem cell expansion cultures can increase the dimensions of in vitro stem cell cultures from 2D to 3D. The culture handling process then becomes more efficient compared with conventional 2D cultures. However, the use of spherical plastic microcarriers complicates the monitoring of cell culture. To facilitate monitoring, transparent disc-shaped microcarriers are manufactured using a light-initiated microfluidic printing system and the obtained microcarriers are named as 2.5D microcarrier. The 2.5D microcarriers (diameter/height ≈ 5) enable us to use conventional monitoring tools in 2D-based platform during the in vitro expansion on a 3D culture platform. Surface modification via a 1 h-long poly-dopamine (PDA) reaction can maintain the transparent nature of the microcarriers while optimizing the cell attachment. The surface marker expression and differentiation potential of the 2.5D microcarrier-expanded stem cells reveal that the characteristics and functionalities preserved during expansion. The 2.5D microcarrier is readily integrated into an on-bead assay to conserve reagents and permit a high number (n = 9) of repeated measurements with reliable results. These results demonstrate that the 2.5D microcarrier-based scale-up culture provides a valuable tool for the in vitro expansion of adherent stem cells, especially if repetitive monitoring is required.