168 Cell and Material Interface
7.7 CRYOPROTECTIVE ADDITIVES
CPAs are additives provided to cells before freezing to enhance post-thaw survival.
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CPA can be divided into two different groups
29,30
:
1. Low-molecular-weight CPAs such as glycerol, ethylene (propylene) glycol,
and dimethyl sulfoxide (DMSO), which can penetrate the cell membrane.
2. Non-cell-membrane-penetrating CPAs that usually do not enter inside the
cells, like polymers such as polyvinyl propyliodone, hydroxyl ethyl starch
(HES), and various sugars.
7.8 HISTORY OF CPAs
Ever since the discovery of the role of glycerol in cryopreservation by Polge etal.
in 1949, the use of CPAs has become common practice. Lovelock and Bishop
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later
found that the protective property show