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Cryoprotective agents (CPAs) can be divided into two groups, intracellular and extracellular cryoprotectants. An intracellular CPA is a small molecule which can penetrate the cell membrane. DMSO, glycerol, ethylene glycol, propylene glycol and cell banker series belong to intracellular CPA. An extracellular CPA is a large molecule that is added to the cryoprotectant solution. Sucrose, dextrose, methylcellulose and polyvinylpyrrolidone (PVP) are examples (1).
DMSO has been successfully used for cryopreservation in a variety of cell types, including stem cells and dendritic cells which are used for cell therapy. According to the literature(2,3), many authors used freezing media containing FBS/HSA with 10% DMSO.
The use of PVP has been investigated as an alternative to cryopreservation with DMSO and fetal calf serum (FCS) in human adipose tissue-derived adult stem cells (4). The author observed that recovery of cells cryopreserved in 10% PVP with human serum was similar to cells cryopreserved in DMSO with animal serum. In addition, they used methylcellulose either alone or combined with reduced levels of DMSO which indicated that 1% methylcellulose produced comparable results with DMSO concentrations as low as 2% during an apoptosis assay.