Abstract
We developed various novel synthetic polyampholytes via reversible addition fragmentation chain transfer (RAFT) polymerization for cryopreservation of cells. The polymers, in spite of being structurally analogous with each other, showed very different cryoprotective properties. Copolymer of methacrylic acid (MAA) and N, N-dimethylaminoethyl methacrylate (DMAEMA) showed excellent cryoprotective property and the hydrophobic modification of the copolymer enhanced the cell viability significantly. On the other hand, another polymer with similar structure, poly-carboxymethyl betaine (poly-CMB), a zwitterion-type polyampholyte, exhibited no cryoprotective property and the addition of hydrophobicity did not have much effect on the cell viability, whereas a similar zwitterion type polyampholyte, poly-sulfobetaine (poly-SPB), exhibited intermediate cryoprotective property. These findings suggest that cryoprotective property depends to a great extent on the polymer structure and the structural differences affect the interaction among polymer chains in solution.
