Nanoengineered capsules encapsulated with functional cargos (e.g., enzymes) are of interest for various applications including catalysis, bioreactions, sensing, and drug delivery. Herein, we report a facile strategy to engineer enzyme-encapsulated metal–phenolic network (MPN) capsules using enzyme-loaded zeolitic imidazolate framework nanoparticles (ZIF-8 NPs) as templates, which can be removed in a mild condition (e.g., ethylenediaminetetraacetic acid (EDTA) solution). The capsule size (from 250 nm to 1 μm) and thickness (from 9.8 to 33.7 nm) are well controlled via varying the template size and coating time, respectively. Importantly, MPN capsules encapsulated with enzymes (i.e., glucose oxidase) can trigger the intracellular cascade reaction via the exhaustion of glucose to produce H₂O₂ and subsequently generate toxic hydroxyl radicals (^•OH) based on the Fenton reaction via the reaction between H₂O₂ and iron ions in MPN coatings. The intracellular cascade reaction for the generation of ^•OH is efficient to inhibit cancer cell viability, which is promising for the application in chemodynamic therapy.

中文翻译：

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在金属-酚醛网络胶囊中封装酶以触发细胞内级联反应

用功能性货物（例如酶）封装的纳米工程胶囊在各种应用中受到关注，包括催化、生物反应、传感和药物输送。在此，我们报告了一种使用载酶沸石咪唑酯骨架纳米粒子（ZIF-8 NPs）作为模板设计酶包覆金属酚网络（MPN）胶囊的简便策略，该纳米粒子可以在温和条件下（例如乙二胺四乙酸）去除。 (EDTA) 溶液）。胶囊尺寸（从 250 nm 到 1 μm）和厚度（从 9.8 到 33.7 nm）分别通过改变模板尺寸和涂层时间来控制。重要的是，用酶（即葡萄糖氧化酶）封装的 MPN 胶囊可以通过耗尽葡萄糖产生 H ₂ O ₂来触发细胞内级联反应随后通过 H ₂ O ₂与 MPN 涂层中的铁离子之间的反应，基于芬顿反应生成有毒的羟基自由基 ( ^• OH) 。^• OH产生的细胞内级联反应可有效抑制癌细胞活力，有望应用于化学动力学治疗。