In our recent experience, larger PEGs work similarly to smaller PEGs as far
as vitrification goes. Additionally, transferring crystals to a solution of
increased PEG concentration (as compared to mother liquor) can substantially
reduce the amount of cryo needed for freezing and can be more gen
We've been having a discussion in the lab about whether or not
middle-sized PEGs such as 4000 can be expected to serve as
cryoprotectants (and if not, why certain commercial kits are
formulated the way they are). Can anybody shed some light /
references on the question of the size of PEGs vs.
