Structural Insights into Ice Recrystallization Activity of Helical Disubstituted Polypeptoids.

Area of Science:

• Biomaterials Science
• Cryobiology
• Polymer Chemistry

Background:

• Ice recrystallization during freeze-thaw cycles is a major challenge in cryopreservation.
• Natural helical antifreeze proteins (AF(G)Ps) offer a model for ice recrystallization inhibition (IRI).
• Developing synthetic analogs with tunable properties is crucial for effective cryoprotective agents.

Purpose of the Study:

• To synthesize helical disubstituted polypeptoids inspired by natural AF(G)Ps.
• To investigate the structure-activity relationship between polypeptoid structure and IRI activity.
• To evaluate the efficacy of these polypeptoids in cryopreservation of blood cells.

Main Methods:

• Efficient synthesis of helical disubstituted polypeptoids via ring-opening polymerization and thiol-ene click reactions.
• Characterization of polypeptoid structure, including helical stability and domain segregation.
• Assessment of ice-binding interactions and IRI activity.
• Preliminary cryopreservation studies using blood cells and hydroxyethyl starch (HES) as a control.

Main Results:

• Helical polypeptoids with segregated hydrophilic and hydrophobic domains were successfully synthesized.
• Increased hydrophobic domains correlated with stronger ice-binding and higher IRI activity.
• Polypeptoids demonstrated superior post-thaw recovery rates for blood cells compared to HES.
• The synthesized materials exhibited facile synthesis, helical stability, tunability, and biocompatibility.

Conclusions:

• Disubstituted polypeptoids represent a promising, tunable platform for developing advanced cryopreservation materials.
• The structure-IRI activity insights facilitate the rational design of novel cryoprotective agents.
• These findings advance the field of cryobiology and biomaterials for cell preservation.