Na-Complexed Dendritic Polyglycerols for Recovery of Frozen Cells and Their Network in Media.

In this study, a novel phenomenon is identified where precise control of topology and generation of polyglycerol induce the retention of Na ions in biological buffer systems, effectively inhibiting ice crystal growth during cryopreservation. Unlike linear and hyperbranched counterparts, densely-packed hydroxyl and ether groups in 4th-generation dendritic polyglycerol interact with the ions, activating the formation of hydrogen bonding at the ice interface. By inhibiting both intra- and extracellular ice growth and recrystallization, this biocompatible dendritic polyglycerol proves highly effective as a cryoprotectant; hence, achieving the cell recovery rates of ≈134-147%, relative to those of 10% dimethyl sulfoxide, which is a conventional cryoprotectant for human tongue squamous carcinoma (HSC-3) cell line and human umbilical vein endothelial (HUVEC) cells. Further, it successfully recovers the network-forming capabilities of HUVEC cells to ≈89% in tube formation after thawing. The Na ion retention-driven ice-growth inhibition activity in biological media highlights the unique properties of dendritic polyglycerol and introduces a new topological concept for cell-cryoprotectant development.