Nanozymes are nanomaterials with enzyme-like activities. Compared to natural enzymes, nanozymes are more stable and cost-effective, and they have unique properties due to their nanoscale size and surface chemistry. In this review, we summarize ‘signal-on’ nanozyme-based sensors for detecting metal ions, anions, small molecules and proteins. Since protein-based enzymes are already highly active, they were used to detect their inhibitors, resulting in ‘signal-off’ sensors. On the other hand, for nanozymes, target molecules were detected either as a promotor of nanozyme activity or for its ability to selectively remove nanozyme inhibitors. In both cases, ‘signal-on’ detection was achieved. We classify the commonly used nanozymes based on their composition such as metal oxide, gold nanoparticles and other nanomaterials, most of which belong to the oxidase, peroxidase and catalase mimics. The nanozymes can catalyze the oxidation of colorless or non-fluorescent substrates to produce a visual or fluorescent signal. Based on this, this article presents some typical ‘turn-on’ and ‘turn-off–on’ sensors, and we critically review their design principles. At the end, further perspectives for the nanozyme-based sensors are outlined.

中文翻译：

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通过调节纳米酶活性设计信号传感器

纳米酶是具有酶样活性的纳米材料。与天然酶相比，纳米酶更稳定且更具成本效益，并且由于其纳米级尺寸和表面化学性质，它们具有独特的特性。在这篇综述中，我们总结了基于“信号”纳米酶的传感器，用于检测金属离子，阴离子，小分子和蛋白质。由于基于蛋白质的酶已经具有很高的活性，因此可用于检测其抑制剂，从而产生“信号关闭”传感器。另一方面，对于纳米酶，检测到靶分子或者作为纳米酶活性的促进剂，或者其选择性去除纳米酶抑制剂的能力。在这两种情况下，都实现了“信号接通”检测。我们根据其组成对常用的纳米酶进行分类，例如金属氧化物，金纳米颗粒和其他纳米材料，其中大多数属于氧化酶，过氧化物酶和过氧化氢酶模拟物。纳米酶可以催化无色或非荧光底物的氧化以产生视觉或荧光信号。基于此，本文介绍了一些典型的“开启”和“关闭”传感器，我们将严格审查它们的设计原理。最后，概述了基于纳米酶的传感器的其他观点。