Chitosan, known for its appealing biological properties in packaging and biomedical applications, faces challenges in achieving a well-organized crystalline structure for mechanical excellence under mild conditions. Herein, we propose a facile and mild bioengineering approach to induce organized assembly of amorphous chitosan into mechanically strong bio-composite via incorporating a genetically engineered insect structural protein, the cuticular protein hypothetical-1 from the (CPH-1). CPH-1 exhibits high binding affinity to chitosan via hydrogen-bonding interactions. Simply mixing a small proportion (0.5 w/w%) of bioengineered CPH-1 protein with acidic chitosan precursor induces the amorphous chitosan chains to form fibrous networks with hydrated chitosan crystals, accompanied with a solution-to-gel transition. We deduce that the water shell destruction driven by strong protein-chitosan interactions, triggers the formation of well-organized crystalline chitosan, which therefore offers the chitosan with significantly enhanced swelling resistance, and strength and modulus that outperforms that of most reported chitosan-based materials as well as petroleum-based plastics. Moreover, the composite exhibits a stretch-strengthening behavior similar to the training living muscles on cyclic load. Our work provides a route for harnessing the CPH-1-chitosan interaction in order to form a high-performance, sustainably sourced bio-composite.

中文翻译：

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通过引入重组昆虫结构蛋白OfCPH-1将壳聚糖组织组装成机械强度高的生物复合材料

壳聚糖以其在包装和生物医学应用中具有吸引力的生物特性而闻名，但在温和条件下实现组织良好的晶体结构以实现卓越的机械性能面临着挑战。在此，我们提出了一种简便温和的生物工程方法，通过掺入基因工程昆虫结构蛋白（来自（CPH-1）的角质蛋白假设-1），诱导无定形壳聚糖有组织地组装成机械强度高的生物复合材料。 CPH-1 通过氢键相互作用表现出与壳聚糖的高结合亲和力。只需将一小部分 (0.5 w/w%) 生物工程 CPH-1 蛋白与酸性壳聚糖前体混合，即可诱导无定形壳聚糖链与水合壳聚糖晶体形成纤维网络，并伴随溶液到凝胶的转变。我们推断，由强蛋白质-壳聚糖相互作用驱动的水壳破坏，触发了组织良好的结晶壳聚糖的形成，因此使壳聚糖具有显着增强的抗溶胀性以及优于大多数报道的基于壳聚糖的材料的强度和模量以及石油基塑料。此外，该复合材料表现出类似于在循环负荷下训练活体肌肉的拉伸强化行为。我们的工作提供了一种利用 CPH-1-壳聚糖相互作用形成高性能、可持续来源的生物复合材料的途径。