Cell freezing:
Sterility, mycoplasma and endotoxin tests were performed on the cell supernatant. 1ml of washing solution (PBS / 5% FBS) was added to 1×107 cells. The cells were then placed on ice for 10 min and then they were added to the freezing solution (20% DMSO, 40% HSA, 40% PBS) and placed in liquid nitrogen.