Microplate-Based Cryopreservation of Adherent-Cultured Human Cell Lines Using Amino Acids and Proteins.

With the progression of regenerative medicine and cell therapy, the importance of cryopreservation techniques for cultured cells continues to rise. Traditional cryoprotectants, such as dimethyl sulfoxide and glycerol, are effective in cryopreserving suspended cells, but they do not demonstrate sufficient efficacy for two-dimensional (2D)-cultured cells. In the past decade, small molecules and polymers have been studied as cryoprotectants.

Protein-Stabilizing Effect of Amphiphilic Block Copolymers with a Tertiary Sulfonium-Containing Zwitterionic Segment.

Tertiary sulfonium-containing zwitterionic block copolymers consisting of -acryloyl-l-methionine methyl sulfonium salt (A-Met(S)-OH) and -butyl acrylate (BA) were newly synthesized to develop a novel protein stabilizer. The zwitterionic block copolymers were prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization of BA using a hydrophilic macro-chain-transfer agent (CTA) obtained from -acryloyl-l-methionine (A-Met-OH) and subsequent postmodification. RAFT polymerization of A-Met-OH using poly(BA) macro-CTA, followed by postmodification, also afforded the target poly(A-Met(S)-OH)--poly(BA).

Synthesis of Zwitterionic Polymers Containing a Tertiary Sulfonium Group for Protein Stabilization.

The present study demonstrates the controlled synthesis and biological potential of poly( N-acryloyl-l-methionine methyl sulfonium salt)s (poly(A-Met(S)-OH)s), which mimic dimethylsulfoniopropionate (DMSP), a compound produced by marine algae to protect their proteins. The novel sulfonium-containing zwitterionic polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of the amino acid-based monomer N-acryloyl-l-methionine (A-Met-OH) followed by a postmodification process in which the sulfide groups were reacted with iodomethane. The DMSP-mimic zwitterionic macromolecules were shown for the first time to exhibit low cytotoxicity and the ability to stabilize proteins.