Single cell derived spheres of umbilical cord mesenchymal stem cells enhance cell stemness properties, survival ability and therapeutic potential on liver failure.

Umbilical cord mesenchymal stem cells (UCMSCs) have shown great potentials in regenerative medicine for their extensive sources, multilineage differentiation potential, low immunogenicity and self-renewal ability. However, the clinical application of UCMSCs still confronts many challenges including the requirement of large quantity of cells, low survival ability in vivo and the loss of main original characteristics due to two-dimensional (2D) culture. The traditional three-dimensional (3D)-spheroid culture can mimic in vivo conditions, but still has limitations in clinical application due to large size of spheroid against direct injection and inner cell death. Based on self-renewal tenet, we produced single cell derived sphere (SCDS) of UCMSCs through combining single cell pattern on chip with 3D culture. Compared with the 2D and traditional 3D culture, SCDS culture has many advantages to meet clinical requirements, including small size, higher abilities of survival and migration, and stronger hypoxia resistance and stemness maintenance. Furthermore, SCDS culture promotes angiogenesis in UCMSCs-xenografts and displays greater therapeutic potential on acute liver failure (ALF) in vivo. Our results suggest that SCDS culture may serve as a simple and effective strategy for UCMSCs optimization to meet clinical demand.