Dual-Functionalized Zwitterionic Polymers for Cell Cryopreservation

Cryopreservation is an essential technique for the long-term preservation of cells. Some cells are challenging to cryopreserve, and novel cryoprotective agents are required. We previously reported a zwitterionic polymer (poly(ZI)) as a cryoprotectant that forms a polymer matrix surrounding the cells and partially prevents intracellular ice formation. In this study, we developed a novel zwitterionic copolymer (poly(ZI-C₁₆)) with an improved cryoprotective ability. Poly(ZI-C₁₆) contains long alkyl chains, which enable poly(ZI-C₁₆) to anchor to the cell surface and consequently strengthen the polymer matrix. In addition, because poly(ZI-C₁₆) is cationic, it enters cells and directly prevents intracellular ice formation. Due to its dual functions, poly(ZI-C₁₆) demonstrated a higher cryoprotective effect than the original poly(ZI). This molecular design for dual functionalization provides an efficient approach to cryopreservation.