Silk fibroin is a semicrystalline protein used as a renewable polymer source and as a biomaterial platform, but existing methods to synthetically modify fibroin suffer from low efficiencies that can limit the protein's utility. This work reports on a mild synthesis that results in a 2-fold increase in carboxylation through the disruption of noncovalent interactions during the reaction. Importantly, silk fibroin maintains its ability to form β-sheets that are critical for tailoring mechanical and degradation properties, as well as for rendering solid constructs (e.g., films and scaffolds) insoluble in water. Increasing carboxyl functionalization affords control over protein charge, which permits tailoring the loading and release of small molecules using electrostatic interactions. Disruption of noncovalent interactions during aqueous carbodiimide coupling also significantly enhances conjugation efficiency of molecules containing primary amine groups, thus enabling high degrees of functionalization with biological molecules, such as proteins and peptides, for biomaterial applications.

中文翻译：

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通过破坏非共价相互作用提高丝素蛋白的羧化效率。

丝素蛋白是一种半结晶蛋白，可用作可再生的聚合物来源和生物材料平台，但是现有的合成修饰丝蛋白的方法效率低，这可能会限制该蛋白的用途。这项工作报道了温和的合成，通过破坏反应过程中的非共价相互作用，导致羧化反应增加了2倍。重要的是，丝素蛋白保持其形成β片的能力，这对于调节机械和降解性能以及使固体结构（例如薄膜和支架）不溶于水至关重要。羧基功能化程度的提高提供了对蛋白质电荷的控制，从而允许使用静电相互作用调整小分子的负载和释放。