Synthesis of Selenium-containing Polypeptides with Antioxidation and Ice-control Properties for Cryopreservation

Cryopreservation is essential for cell therapy and regenerative medicine, while macromolecular cryoprotectants play a crucial role in mitigating the freeze injuries caused by subzero temperatures. Physical damages induced by ice crystals and oxidative damages triggered by reactive oxygen species are two major types of injuries during cryopreservation. Herein, a series of selenium-containing block copolypeptides are synthesized from L-selenomethionine and N ′-Cbz-L-ornithine, which demonstrate ice-controlling properties in ice recrystallization inhibition, ice nucleation temperature, and ice crystal shaping. Owing to the significant antioxidant activities, these selenium-containing polypeptides can also effectively scavenge H 2 O 2 and alleviate the oxidative injury. In serum-free cryopreservation of L929 fibroblasts, the cryoprotectant consisting of selenium-containing polypeptides, 5% dimethyl sulfoxide (DMSO), and trehalose achieves over 80% post-thaw survival, maintaining normal proliferation superior to 10% DMSO and intact cellular integrity. This work provides a valuable insight into applications of selenium-containing polypeptides in cryopreservation of cells by reducing oxidative injuries and moderate ice-induced damages.