Fig. 1

Cryopreservation and storage stability of MSC overexpressing CD::UPRT::GFP. (A) Cell images and transfection efficiency FACS profile of MSC overexpressing CD::UPRT::GFP before cryopreservation. Briefly, cells were plated and left overnight before addition of polyplex. 24 h post transfection, cells from multiple dishes were harvested and combined to obtain sufficient cells for storage and analysis. Flow cytometry (FACS) analysis was performed using CytoFLEX LX equipped with a FITC channel for GFP detection. Representative images are displayed. (B) Cell viability percentage was assessed using dye-exclusion assay (AO/DAPI, Chemometec) and transfection efficiency (flow cytometry analysis) for cryopreserved MSC overexpressing CD::UPRT::GFP at 5 months, 8 months and 11 months post cryopreservation. Significant differences in transfection efficiencies between modified MSCs before and post cryopreservation were calculated using two-tailed Student’s t test. **P < 0.005, ***P < 0.001. (C) MSC overexpressing CD::UPRT::GFP was stocked at 1 M, 20 M and 30 M/mL, and cell viability was measured 5 months post cryopreservation. (D) Post-thaw modified cells were spun down to remove CPA and resuspended in hypothermic storage solution HTS-FRS to assess stability at room temperature and 4 °C. Data of biological triplicates (n = 3) were expressed as mean ± SD