Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, Zhejiang, People's Republic of China.
Nanotechnology. 2013 Jan 11;24(1):015503. doi: 10.1088/0957-4484/24/1/015503. Epub 2012 Dec 5.
Various DNAs were employed as hosts to investigate the sequence-dependent formation of fluorescent Au nanoclusters (Au NCs) in aqueous solution. By comparison among hairpin DNAs (HP-DNAs) with a pristine stem segment and varied loop sequences, we found that the emission behavior of the HP-DNA-hosted Au NCs is dependent on the loop sequences. The most efficient host to produce fluorescent Au NCs is the cytosine loop. However, relative to the cytosine and guanine loops, the loop composed of thymine as well as adenine produces Au NCs with a much weaker emission. Additionally, the emission behavior of Au NCs hosted by the single-stranded DNAs (ss-DNAs) with an identical base composition to the corresponding HP-DNAs still exhibits a cytosine-rich dependence. The fully matched DNAs seem to be less efficient than the corresponding loop and ss-DNA structures. Furthermore, the emission properties of HP-DNA-hosted Au NCs can be modulated by the loop length. The sequence-dependent formation of fluorescent Au NCs is believed to be caused by differences in binding nucleophilicity of the DNA heterocyclic nitrogen and exocyclic keto groups to the hydrolyzed Au(III) species. This work demonstrates the role of sequence in producing Au NCs that could serve as promising fluorescent nanoprobes in biosensing and DNA-hosted Au nanomaterials.
多种 DNA 被用作宿主，以研究在水溶液中荧光金纳米团簇（Au NCs）的序列依赖性形成。通过比较具有原始茎段和不同环序列的发夹 DNA（HP-DNAs），我们发现 HP-DNA 宿主 Au NCs 的发射行为取决于环序列。产生荧光 Au NCs 的最有效宿主是胞嘧啶环。然而，与胞嘧啶和鸟嘌呤环相比，由胸腺嘧啶和腺嘌呤组成的环产生的 Au NCs 的发射强度要弱得多。此外，与相应的 HP-DNAs 具有相同碱基组成的单链 DNA（ss-DNAs）所承载的 Au NCs 的发射行为仍然表现出富含胞嘧啶的依赖性。完全匹配的 DNA 似乎不如相应的环和 ss-DNA 结构有效。此外，HP-DNA 承载的 Au NCs 的发射特性可以通过环长度进行调节。荧光 Au NCs 的序列依赖性形成被认为是由 DNA 杂环氮和外环酮基对水解的 Au(III)物种的亲核性差异引起的。这项工作证明了序列在产生 Au NCs 中的作用，这些 Au NCs 可以作为生物传感和 DNA 承载金纳米材料中有前途的荧光纳米探针。
