Protein hydrogels constructed from recombinant proteins have attracted increasing interests for fundamental biological studies as well as applications in biomedical engineering field. In such protein hydrogels, biochemical and physical properties of protein hydrogels are often coupled to each other, making it challenging to investigate the individual effect of chemical and physical cues on cells. Moreover, laborious engineering is often required to incorporate different protein ligands into such hydrogels. To address these challenges, functionalizing a blank slate protein hydrogel is an attractive approach. However, conjugating ligands to such a blank slate protein hydrogel is challenging, as existing bioconjugation methods developed in synthetic polymer hydrogels cannot be readily adapted for protein hydrogels, significantly impeding the use of this approach in the field. Here we report a facile, general, and robust method, which is based on the SpyCatcher-SpyTag chemistry, to covalently functionalize the “blank slate” of protein hydrogels using genetically encoded interacting partners. We demonstrate that this novel method enables covalent conjugation of a wide variety of ligands, including full-length intact folded proteins, to a blank slate protein hydrogel, and allows for the decoupling of biochemical and physical properties of hydrogels from each other and investigating the individual effect of biochemical and mechanical cues on cell behaviors. To our best knowledge, this is the first general approach enabling functionalization of protein hydrogels, and we anticipate that this novel approach will find a broad range of uses in protein-based biomaterials for applications in biomedical engineering.

中文翻译：

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装饰一个空白的板岩蛋白质水凝胶：一种功能强大的蛋白质水凝胶的通用和鲁棒的方法。

由重组蛋白质构建的蛋白质水凝胶对于基础生物学研究以及在生物医学工程领域中的应用引起了越来越多的兴趣。在这样的蛋白质水凝胶中，蛋白质水凝胶的生化和物理特性经常相互耦合，这使得研究化学和物理线索对细胞的个体作用变得困难。而且，经常需要费力的工程来将不同的蛋白质配体掺入这种水凝胶中。为了解决这些挑战，功能化空白板岩蛋白水凝胶是一种有吸引力的方法。但是，将配体与这种空白的板状蛋白质水凝胶缀合具有挑战性，因为在合成聚合物水凝胶中开发的现有生物缀合方法无法轻易地适用于蛋白质水凝胶，严重阻碍了该方法在现场的使用。在这里，我们报告一种基于SpyCatcher-SpyTag化学方法的简便，通用且可靠的方法，该方法使用遗传编码的相互作用伴侣将蛋白质水凝胶的“空白”共价功能化。我们证明了这种新方法能够使多种配体（包括全长完整折叠的蛋白质）共价缀合至空白的板状蛋白质水凝胶，并使水凝胶的生化和物理性质彼此脱钩并进行个体研究生化和机械线索对细胞行为的影响。据我们所知，这是第一个实现蛋白质水凝胶功能化的通用方法，