The distribution of cryoprotective agents into lipid interfaces

Capillary rise measurements indicate that the cryoprotective agents dimethyl sulfoxido, glycerol, sucrose, hydroxy ethyl starch, polyvinyl pyrrolidone, and dextran are surface active, suggesting the possibility that they distribute into the lipids of the cell membrane. However, Langmuir trough experiments and surface pressure-temperature measurements using aliphatic alcohols and cephalin show that these more efficient surfactants exclude the glycerol and DMSO from the interface. We conclude that DMSO and glycerol must exert their influence on the aqueous side of the monolayer. In contrast, the data for PVP indicate that it enters the lipid monolayer, but can easily be excluded by surface pressure.