Biofunctional hydrogels prepared by a peroxidase, especially horseradish peroxidase (HRP), serve as an excellent class of materials or platform for the development of cellular scaffolds because their biocompatibility and mild and tunable reaction conditions provide them with desirable properties. In this focus review, we summarize our decade of research into HRP-mediated fabrication of biofunctional hydrogels and their applications, in particular cell culture scaffolds. A brief overview of potential substrates employed in HRP and improvement of the HRP hydrogelation system from the initial step until the hydrogen peroxide removal stage in an effort to meet environmental standards is discussed. We highlight our system and describe its biocompatibility and ability to functionalize molecules to support biofabrication by increasing cellular adhesiveness, retaining growth factor affinity, and finally accelerating the formation of two- and three-dimensional multicellular architectures. In the last section, we outline the adoption of hydrogelation as a self-standing, compartmentalized reaction system, i.e., the use of hydrogel marble to conduct cell-free biosynthesis. We believe that this HRP-mediated hydrogel system offers great potential not only as a cell culture scaffold but also for various biomedical applications. Biofunctional hydrogels were formed by horseradish peroxidase (HRP)-catalyzed cross-linking reaction. Poly(ethylene glycol) (PEG) incorporated with phenol or thiol group was used as a base polymer to form irreversible or redox responsive cross-links, respectively. Thiolated PEGs showed slower hydrogelation kinetics than phenolated ones; however, in the presence of phenolic small compounds, the cross-linking reaction was promoted without the aid of exogenous hydrogen peroxide. Moreover, in situ incorporation of bioactive entities, such as proteins, realized biofunctionalization of hydrogels for potential applications for bioengineering and biomedical applications.

中文翻译：

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过氧化物酶催化交联反应介导的基于聚乙二醇的生物功能水凝胶

由过氧化物酶，尤其是辣根过氧化物酶 (HRP) 制备的生物功能水凝胶可作为一类优秀的材料或平台用于开发细胞支架，因为它们的生物相容性和温和可调的反应条件为它们提供了理想的特性。在这篇重点综述中，我们总结了我们十年来对 HRP 介导的生物功能水凝胶制造及其应用的研究，特别是细胞培养支架。简要概述了 HRP 中使用的潜在底物以及从初始步骤到过氧化氢去除阶段的 HRP 水凝胶系统的改进，以达到环境标准。我们强调了我们的系统，并描述了它的生物相容性和功能化分子的能力，通过增加细胞粘附性、保持生长因子亲和力并最终加速二维和三维多细胞结构的形成来支持生物制造。在最后一节中，我们概述了采用水凝胶作为独立的、分隔的反应系统，即使用水凝胶大理石进行无细胞生物合成。我们相信，这种 HRP 介导的水凝胶系统不仅作为细胞培养支架，而且在各种生物医学应用方面都具有巨大的潜力。生物功能水凝胶是由辣根过氧化物酶 (HRP) 催化的交联反应形成的。与苯酚或硫醇基团结合的聚（乙二醇）（PEG）用作基础聚合物，分别形成不可逆或氧化还原响应交联。硫醇化 PEG 的水凝胶化动力学比酚化 PEG 慢；然而，在酚类小化合物的存在下，交联反应在没有外源性过氧化氢的帮助下被促进。此外，生物活性实体（如蛋白质）的原位掺入实现了水凝胶的生物功能化，以用于生物工程和生物医学应用的潜在应用。