The effects of β-tricalcium phosphate 3D scaffold in-situ cryopreservation on the migration rate and osteogenic ability of mesenchymal stem cells

To readily supply seed cells for tissue engineering and ensure their constant availability for experiments, it is imperative to establish an in-situ cryopreservation method for cell storage. We investigated the effects of a β-tricalcium phosphate (β-TCP) 3D scaffold in-situ cryopreservation method on the migration rate and osteogenic ability of mesenchymal stem cells (MSCs). Compared to using a 2D plate culture and trypsinized cryopreservation, MSCs on β-TCP 3D scaffolds demonstrated a higher amplification rate, and the harvest and survival rates (HSR) increased from 55.9 to 81.3% when the 3D in-situ cryopreservation method was applied. The cell migration rate and alkaline phosphatase (ALP) activity were unaffected after in-situ cryopreservation, and unexpectedly, the Specific ALP activity of migrating cells was higher than that of non-cryopreserved cells, suggesting that the cell-scaffold combination could be cryopreserved using the present protocol without loss of proliferative or osteogenic potential. These findings highlight a methodology for 3D scaffold in-situ cryopreservation and passage for MSC production in bone tissue engineering, and present the possibility of designing a perfusion cells/scaffold factory for scale-up production.