Catalytic applications of DNA duplexes containing Ag⁺-mediated cytosine–cytosine base pairs (C-Ag⁺-C) have not been well investigated. In this study, we demonstrate a novel approach for forming highly active DNA-capped Ag nanoparticle (DNA-AgNP) catalysts for the reduction of 4-nitrophenol (4-NP) using sodium borohydride (NaBH₄). This approach is based on the in situ generation of DNA-AgNPs from DNA duplexes containing C-Ag⁺-C (DNA duplex-Ag⁺). UV–vis spectroscopic analysis suggests that the DNA duplex-Ag⁺ complex acts as an excellent catalyst precursor for 4-NP reduction with NaBH₄. Transmission electron microscopy observations of the reaction solution after the 4-NP reduction reaction using DNA duplex-Ag⁺ provided detailed experimental insights into the mechanism of the catalytic activity of DNA duplex-Ag⁺ for 4-NP reduction. In the reaction solution, DNA-AgNPs were initially formed (DNA duplex-Ag⁺ + NaBH₄ → DNA-AgNPs) and then served as water-soluble catalysts for 4-NP reduction. Notably, the catalytic properties of the DNA-AgNPs generated in situ were affected by the DNA strand length and sequence. The properties of DNA duplex-Ag⁺ may provide a new application of DNA molecules containing metallobase pairs as water-soluble catalyst precursors.

中文翻译：

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含有 Ag+ 介导的胞嘧啶-胞嘧啶碱基对的 DNA 双链体作为 NaBH4 减少 4-硝基苯酚的催化剂前体


含有 Ag⁺ 介导的胞嘧啶-胞嘧啶碱基对 （C-Ag⁺-C） 的 DNA 双链体的催化应用尚未得到很好的研究。在这项研究中，我们展示了一种形成高活性 DNA 加帽的 Ag 纳米颗粒 （DNA-AgNP） 催化剂的新方法，用于使用硼氢化钠 （NaBH₄） 还原 4-硝基苯酚 （4-NP）。该方法基于从含有 C-Ag⁺-C （DNA duplex-Ag⁺） 的 DNA 双链体原位生成 DNA-AgNP。紫外-可见光谱分析表明，DNA 双链体-Ag⁺ 复合物是用 NaBH₄ 还原 4-NP 的极好催化剂前体。使用 DNA 双链体-Ag⁺ 对 4-NP 还原反应后反应液的透射电子显微镜观察为 DNA 双链体-Ag⁺ 对 4-NP 还原的催化活性机制提供了详细的实验见解。在反应溶液中，最初形成 DNA-AgNPs（DNA 双链体-Ag⁺ + NaBH₄ → DNA-AgNPs），然后用作 4-NP 还原的水溶性催化剂。值得注意的是，原位生成的 DNA-AgNPs 的催化性质受 DNA 链长度和序列的影响。DNA 双链体-Ag⁺ 的特性可能为含有金属碱基对的 DNA 分子作为水溶性催化剂前体提供了新的应用。