Antifreeze, ice binding and ice nucleating proteins modulate the formation and growth of ice in biological systems, enabling extremophiles to survive in sub-zero temperatures. A common feature is their rigidity, and segregated hydrophobic and hydrophilic domains. It has been demonstrated that increased hydrophobicity in rigid, facially amphipathic, synthetic polymers enhances ice recrystallisation inhibition (IRI) activity, but has not been evaluated in flexible systems. Here photochemical RAFT/MADIX polymerisation is used to obtain well-defined poly(N-vinyl pyrrolidone), PVP, copolymers to probe the impact of hydrophobicity on ice recrystallisation inhibition in a fully flexible polymer system, to increase the understanding on how to mimic antifreeze proteins. It is observed that PVP homopolymers have only very weak, molecular weight dependent, IRI and that hydrophobic co-monomers give very modest changes in IRI, demonstrating that the spacial segregation of ‘philicities’ is crucial, and not just the overall hydrophobic content of the polymer. These results will help design the next generation of IRI active polymers for cryopreservation applications as well as aid our understanding of how biomacromolecules can inhibit ice growth.

中文翻译：

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疏水改性聚（乙烯基吡咯烷酮）共聚物的光聚合和冰重结晶抑制研究

防冻剂、冰结合蛋白和冰成核蛋白调节生物系统中冰的形成和生长，使极端微生物能够在低于零的温度下生存。一个共同的特征是它们的刚性，以及分离的疏水和亲水域。已经证明，刚性、表面两亲性合成聚合物的疏水性增加可增强冰重结晶抑制 (IRI) 活性，但尚未在柔性系统中进行评估。在这里，光化学 RAFT/MADIX 聚合用于获得明确定义的聚（N-乙烯基吡咯烷酮）、PVP、共聚物，以探测疏水性对完全柔性聚合物系统中冰重结晶抑制的影响，以增加对如何模拟防冻剂的理解蛋白质。据观察，PVP 均聚物仅具有非常弱的、依赖于分子量的、IRI 和疏水性共聚单体在 IRI 中产生非常温和的变化，表明“亲和性”的空间分离是至关重要的，而不仅仅是聚合物的整体疏水性含量。这些结果将有助于设计用于低温保存应用的下一代 IRI 活性聚合物，并有助于我们了解生物大分子如何抑制冰生长。