The encapsulation of catalytic active centers into polymer hydrogels represents a simple and effective strategy for enzyme mimicry. Current methods only enable the preparation of macroscopic enzyme carriers, which are far from natural enzymes in terms of their sizes, local chemical and physical properties, and catalytic activities. In this work, a nanogel strategy to immobilize hemin, a mimic of the active center for horseradish peroxidase (HRP), into a polyacrylamide (PAAm) matrix is demonstrated. Hemin was modified using N-(3-aminopropyl) methacrylamide hydrochloride (APMA) and the modified hemin together with excess APMA were covalently incorporated into PAAm nanogels. The resulting Hem@Gel shows enhanced catalytic activity and environmental tolerance compared with hemin and unmodified nanogel Hem/Gel, which has been demonstrated via the catalytic oxidation of various organic dyes. Further characterization and molecular simulations reveal the Fe–N coordination between the pendant groups and the enrichment of dye molecules and H₂O₂ in PAAm nanogels, which together enhance the local reaction rate and realize an overall improvement in catalytic efficiency.

中文翻译：

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通过共价固定在聚合物纳米凝胶中来增强血红素的过氧化物酶模拟活性

催化活性中心到聚合物水凝胶中的包封代表了一种简单有效的酶模拟策略。当前的方法仅能够制备宏观酶载体，就其大小，局部化学和物理性质以及催化活性而言，它们与天然酶相差甚远。在这项工作中，展示了一种纳米凝胶策略，可将血红素（辣根过氧化物酶（HRP）的活性中心的模拟物）固定到聚丙烯酰胺（PAAm）基质中。用N修饰Hemin将-（3-氨基丙基）甲基丙烯酰胺盐酸盐（APMA）和改性的血​​红素与过量的APMA共价结合到PAAm纳米凝胶中。与hemin和未修饰的纳米凝胶Hem / Gel相比，所得Hem @ Gel显示出增强的催化活性和环境耐受性，这已通过各种有机染料的催化氧化得到证实。进一步的表征和分子模拟揭示了悬垂基团之间的Fe–N配位以及PAAm纳米凝胶中染料分子和H ₂ O ₂的富集，它们共同提高了局部反应速率并实现了催化效率的整体提高。