Nucleic acids are considered not only extraordinary carriers of genetic information but also are perceived as the perfect elemental materials of molecular recognition and signal transduction/amplification for assembling programmable artificial reaction networks or circuits, which are similar to conventional electronic logic devices. Among these sophisticated DNA-based reaction networks, catalytic hairpin assembly (CHA), hybridization chain reaction (HCR), and DNAzyme represent the typical nonenzymatic amplification methods with high robustness and efficiency. Furthermore, their extensive hierarchically cascade integration into multi-layered autonomous DNA circuits establishes novel paradigms for constructing more different catalytic DNA nanostructures and for regenerating or replicating diverse molecular components with specific functions. Various DNA and inorganic nanoscaffolds have been used to realize the surface-confined DNA reaction networks with significant biomolecular sensing and signal-regulating functions in living cells. Especially, the specific aptamers and metal-ion-bridged duplex DNA nanostructures could extend their paradigms for detecting small molecules and proteins in even living entities. Herein, the varied enzyme-free DNA circuits are introduced in general with an extensive explanation of their underlying molecular reaction mechanisms. Challenges and outlook of the autonomous enzyme-free DNA circuits will also be discussed at the end of this chapter.

中文翻译：

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基于自主的无酶DNA电路的高性能生物传感。

核酸不仅被认为是遗传信息的特殊载体，而且被认为是用于组装可编程人工反应网络或电路的分子识别和信号转导/扩增的理想基本材料，类似于常规电子逻辑设备。在这些基于DNA的复杂反应网络中，催化发夹装配（CHA），杂交链反应（HCR）和DNAzyme代表了具有高鲁棒性和效率的典型非酶扩增方法。此外，它们广泛的分层级联到多层自主DNA回路中，建立了新颖的范例，可用于构建更多不同的催化DNA纳米结构，以及再生或复制具有特定功能的各种分子成分。各种DNA和无机纳米支架已被用于实现在活细胞中具有显着生物分子传感和信号调节功能的表面受限的DNA反应网络。特别是，特定的适体和金属离子桥连的双链DNA纳米结构可以扩展其用于检测甚至是活实体中的小分子和蛋白质的范例。在本文中，通常引入各种无酶的DNA回路，并对其潜在的分子反应机理进行广泛的解释。本章末尾还将讨论自主无酶DNA电路的挑战和前景。特定的适体和金属离子桥接的双链DNA纳米结构可以扩展其用于检测甚至是活实体中的小分子和蛋白质的范例。在本文中，通常引入各种无酶的DNA回路，并对其潜在的分子反应机理进行广泛的解释。本章末尾还将讨论自主无酶DNA电路的挑战和前景。特定的适体和金属离子桥接的双链DNA纳米结构可以扩展其用于检测甚至是活实体中的小分子和蛋白质的范例。在本文中，通常引入各种无酶的DNA回路，并对其潜在的分子反应机理进行广泛的解释。本章末尾还将讨论自主无酶DNA电路的挑战和前景。