Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Anal Chem. 2022 Jun 7;94(22):8041-8049. doi: 10.1021/acs.analchem.2c01354. Epub 2022 May 26.
It is intriguing to modulate the fluorescence emission of DNA-scaffolded silver nanoclusters (AgNCs) via confined strand displacement and transient concatenate ligation for amplifiable biosensing of a DNA segment related to SARS-CoV-2 (DNA). Herein, three stem-loop structural hairpins for signaling, recognizing, and assisting are designed to assemble a variant three-way DNA device (3WDD) with the aid of two linkers, in which orange-emitting AgNC (AgNC) is stably clustered and populated in the closed loop of a hairpin reporter. The presence of DNA initiates the toehold-mediated strand displacement that is confined in this 3WDD for repeatable recycling amplification, outputting numerous hybrid DNA-duplex conformers that are implemented for a transient "head-tail-head" tandem ligation one by one. As a result, the AgNC-hosted hairpin loops are quickly opened in loose coil motifs, bringing a significant fluorescence decay of multiple clusters dependent on DNA. Demonstrations and understanding of the tunable spectral performance of a hairpin loop-wrapped AgNC via switching 3WDD conformation would be highly beneficial to open a new avenue for applicable biosensing, bioanalysis, or clinical diagnostics.
通过受限的链置换和瞬时连接的方式来调节 DNA 支架银纳米团簇（AgNCs）的荧光发射，这对于扩增与 SARS-CoV-2（DNA）相关的 DNA 片段的可扩增生物传感是很有趣的。在此，设计了三个用于信号转导、识别和辅助的茎环结构发夹，借助两个接头组装了一种变体三链 DNA 器件（3WDD），其中橙色发射的 AgNC（AgNC）稳定地聚集在发夹报告器的闭环中。DNA 的存在会引发引发链置换，这种链置换在 3WDD 中受到限制，可以进行可重复的循环扩增，输出大量的杂交 DNA-双链体构象，这些构象一个接一个地进行瞬时“头-尾-头”串联连接。结果，AgNC 宿主发夹环迅速以松散的线圈模式打开，导致多个簇的荧光显著衰减，这取决于 DNA。通过切换 3WDD 构象来调节发夹环包裹的 AgNC 的可调谐光谱性能的演示和理解，将非常有利于为应用生物传感、生物分析或临床诊断开辟新途径。
