Preparation of ice-nucleating glycopolymers from poly(methyl vinyl ether-alt-maleic anhydride) by modification with saccharides

Abstract

Ice formation can cause a serious of cryoinjuries to cells, and development of biocompatible cryoprotectants for ice control is of great importance. Herein, ice-nucleating glycopolymers are synthesized from the alternating copolymer, poly(methyl vinyl ether-alt-maleic anhydride) (PMVEA), by modification with small saccharides via one-step esterification. The prepared water-soluble glycopolymers can trigger ice nucleation at −14 to −12 °C, significantly higher than deionized water, linear poly(vinyl alcohol), and poly(ethylene glycol) (PEG). The structural differences in monosaccharide, disaccharide and trisaccharide-grafted glycopolymers have positive impacts on the chemically induced ice nucleation and the ice crystal morphology, but all of them have weak activity to inhibit ice recrystallization, similar like PEG. Analyses of differential scanning calorimetry and low field nuclear magnetic resonance suggest that the PMVEA-based glycopolymers, which can be self-associated in nanoscale by the alternating structure of hydrophobic methoxyl and hydrophilic saccharide/carboxyl groups, could have strong interactions with water molecules, thus initiating ice nucleation. Particularly, incorporation of trehalose-modified PMVEA in alginate hydrogel can enhance cryosurvival of Lactobacillus rhamnosus after cryopreservation at −20 °C in comparison with cryostorage at −80 °C. This work provides a feasible approach for preparation of ice-nucleating macromolecules for ice control during cryopreservation of cells.