Bioinspired Cryoprotectants of Glucose-Based Carbon Dots

In nature, antifreeze proteins (AFPs) present in plants, fish, and insects living in cold regions exhibit unique abilities to decrease the freezing temperature of water, inhibiting ice growth and recrystallization. However, AFPs suffer from difficult extraction, low stability, and potential immunogenicity, which limit their wide applications in cryopreservation. Thus, AFP-inspired cryoprotectants with low cytotoxicity, simple design, and large-scale production are highly desired. Herein, carbon dots (CDs) from glucose (G-CDs) are synthesized by hydrothermal carbonization. The adsorption on ice crystals provides the G-CDs with an ice-shaping effect while inhibiting ice growth and recrystallization. The high inhibition of ice recrystallization activity and low cytotoxicity of the G-CDs make them promising cryoprotectant materials. Thus, G-CDs without any organic solvent can significantly improve sheep red blood cell recovery to ca. 60%. The use of glucose as a starting material provides these G-CDs with low-cost, biocompatibility, commercial availability, and mass-production characteristics, paving the way for the synthesis of both cryopreservation material CDs from sugars.