As a nanozyme, gold nanoparticles have some advantages compared with natural enzymes, such as stable structure, adjustable catalytic activity, multifunctionality, and recyclability. Due to their special dimension, they are easy to aggregate rapidly and lose their catalytic performance when exposed to normal saline or special pH environment. To avoid such a situation, Au@PNIPAm nanozymes with core–shell structure are constructed and their mimic peroxidase and glucose oxidase enzymatic activities are investigated. Kinetic examinations manifest that Au@PNIPAm nanozymes exhibited a high affinity for 3,3,5,5-tetramethylbenzidine (TMB), hydrogen peroxide (H₂O₂), and glucose. These predominant peroxidase-like and glucose-like oxidase Au@PNIPAm catalytic activities are successfully used in the detection of H₂O₂ or glucose (LOD is 2.43 mM or 5.07 mM). Otherwise, the potential Au@PNIPAm nanozymes are provided with a clear ability for decomposing the intracellular H₂O₂ in living cells. And it could protect cells from oxidative stress damage with inducing by H₂O₂. Therefore, it is easy to consider that Au@PNIPAm nanozymes show a certain possibility to retard cell senescence and increase the production of the hydroxyl radical which could prevent carcinogenesis of the cell.

中文翻译：

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用于葡萄糖检测和细胞内 H2O2 调节的双活性 Au@PNIPAm 纳米酶

作为一种纳米酶，金纳米粒子与天然酶相比具有结构稳定、催化活性可调、多功能、可循环利用等优点。由于其特殊的尺寸，当暴露于生理盐水或特殊pH环境时，它们很容易迅速聚集并失去催化性能。为了避免这种情况，我们构建了具有核壳结构的 Au@PNIPAm 纳米酶，并研究了它们的模拟过氧化物酶和葡萄糖氧化酶的酶活性。动力学检查表明，Au@PNIPAm 纳米酶对 3,3,5,5-四甲基联苯胺 (TMB)、过氧化氢 (H ₂ O ₂) 和葡萄糖。这些主要的过氧化物酶样和葡萄糖样氧化酶 Au@PNIPAm 催化活性成功地用于检测 H ₂ O ₂或葡萄糖（LOD 为 2.43 mM 或 5.07 mM）。否则，潜在的 Au@PNIPAm 纳米酶具有分解活细胞中细胞内 H ₂ O _{2的明显能力。在H 2} O ₂的诱导下，它可以保护细胞免受氧化应激损伤。因此，很容易认为Au@PNIPAm纳米酶具有一定的延缓细胞衰老和增加羟基自由基产生的可能性，从而防止细胞的癌变。