Silk is a natural fiber that surpasses most man-made polymers in its combination of strength and toughness. Silk fibroin, the primary protein component of silk, can be synthetically mimicked by a linear copolymer with alternating rigid and soft segments. Strategies for chemical synthesis of such silk-like polymers have persistently resulted in poor sequence control, long reaction times, and low molecular weights. Here, we present a two-stage approach for rapidly synthesizing silk-like polymers with precisely defined rigid blocks. This approach utilizes solid-phase peptide synthesis to create uniform oligoalanine “prepolymers”, followed by microwave-assisted step-growth polymerization with bifunctional poly(ethylene glycol). Multiple coupling chemistries and reaction conditions were explored, with microwave-assisted click chemistry yielding polymers with M_w ∼ 14 kg/mol in less than 20 min. These polymers formed antiparallel β-sheets and nanofibers, which is consistent with the structure of natural silk fibroin. Thus, our strategy demonstrates a promising modular approach for synthesizing silk-like polymers.

中文翻译：

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微波辐射和点击化学促进了类似丝绸的聚合物的快速合成。

丝绸是一种天然纤维，在强度和韧性方面都超过了大多数人造聚合物。丝素蛋白是丝绸的主要蛋白质成分，可以通过具有交替的刚性和软链段的线性共聚物进行合成模拟。此类丝状聚合物的化学合成策略一直导致不良的序列控制，较长的反应时间和较低的分子量。在这里，我们提出了一种采用两步法快速合成具有精确定义的刚性嵌段的丝状聚合物。这种方法利用固相肽合成来生成均匀的低聚丙氨酸“预聚物”，然后与双功能聚乙二醇进行微波辅助的逐步生长聚合。探索了多种偶联化学和反应条件，在不到20分钟的时间内M _w〜14 kg / mol。这些聚合物形成反平行的β-折叠和纳米纤维，这与天然丝素蛋白的结构一致。因此，我们的策略证明了一种有希望的用于合成丝状聚合物的模块化方法。