Rational design of self-assembled DNA nanostructures has become one of the fastest-growing research areas in molecular science. Particular attention is focused on the development of dynamic DNA nanodevices whose configuration and function are regulated by specific chemical inputs. Herein, we demonstrate the concept of metal-mediated base-pair switching to induce inter- and intramolecular DNA strand displacement in a metal-responsive manner. The 5-hydroxyuracil (U^OH) nucleobase is employed as a metal-responsive unit, forming both a hydrogen-bonded U^OH–A base pair and a metal-mediated U^OH–Gd^III–U^OH base pair. Metal-mediated strand displacement reactions are demonstrated under isothermal conditions based on the base-pair switching between U^OH–A and U^OH–Gd^III–U^OH. Furthermore, metal-responsive DNA tweezers and allosteric DNAzymes are developed as typical models for DNA nanodevices simply by incorporating U^OH bases into the sequence. The metal-mediated base-pair switching will become a versatile strategy for constructing stimuli-responsive DNA nanostructures, expanding the scope of dynamic DNA nanotechnology.

自组装DNA纳米结构的合理设计已成为分子科学中发展最快的研究领域之一。特别关注的是动态 DNA 纳米器件的开发，其配置和功能由特定的化学输入调节。在此，我们演示了金属介导的碱基对转换的概念，以金属响应的方式诱导分子间和分子内 DNA 链置换。5-羟基尿嘧啶 ( U ^OH ) 核碱基用作金属响应单元，形成氢键U ^OH –A 碱基对和金属介导的U ^OH –Gd ^III – U ^OH碱基对。基于U ^OH –A 和U ^OH –Gd ^III – U ^OH之间的碱基对转换，在等温条件下证明了金属介导的链置换反应。此外，只需将U ^OH碱基合并到序列中，即可将金属响应 DNA 镊子和变构 DNAzyme 开发为 DNA 纳米器件的典型模型。金属介导的碱基对转换将成为构建刺激响应DNA纳米结构的通用策略，扩大动态DNA纳米技术的范围。