Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan.
Analyst. 2011 Sep 21;136(18):3623-8. doi: 10.1039/c1an15258k. Epub 2011 Jul 21.
A simple strategy for the preparation of strongly fluorescent and stable DNA-Cu/Ag NCs from reduction of AgNO(3) and Cu(NO(3))(2) by NaBH(4) in the presence of DNA having a sequence 5'-CCCTTAATCCCC-3' has been demonstrated. Fluorescence, absorption, X-ray photoelectron spectroscopy (XPS), and electrospray ionization-mass spectrometry (ESI-MS) measurements have been applied to the characterization of the DNA-Cu/Ag NCs. The ESI-MS data reveal that each DNA-Cu/Ag NC contained 2 Ag and 1 Cu atoms. The interactions among DNA with the Ag and Cu atoms are further supported by the data of low-temperature fluorescence. In the presence of Cu(2+) ions, the reaction time is 1.5 h, which is much shorter than that (120 h) for the preparation of Ag-DNA NCs that are prepared in a mixture of AgNO(3), NaBH(4) and DNA without containing Cu(2+) ions. Relative to the DNA-Ag NCs, the DNA-Cu/Ag NCs have greater fluorescence (quantum yield 51.2% vs. 11.5%). The DNA-Cu/Ag NCs are highly sensitive and selective for the detection of single-stranded DNA binding protein (SSB), with a linear range 1-50 nM and a limit of detection 0.2 nM at a signal-to-ratio of 3.
已证明，通过在具有序列 5'-CCCTTAATCCCC-3' 的 DNA 存在下，用 NaBH4 将 AgNO3 和 Cu(NO3)2 还原，可制备强荧光且稳定的 DNA-Cu/Ag NCs 的简单策略。已应用荧光、吸收、X 射线光电子能谱 (XPS) 和电喷雾电离质谱 (ESI-MS) 测量对 DNA-Cu/Ag NCs 进行了表征。ESI-MS 数据表明，每个 DNA-Cu/Ag NC 含有 2 个 Ag 和 1 个 Cu 原子。低温荧光数据进一步支持了 DNA 与 Ag 和 Cu 原子之间的相互作用。在 Cu(2+) 离子存在下，反应时间为 1.5 小时，比在不含 Cu(2+) 离子的 AgNO3、NaBH4 和 DNA 的混合物中制备 Ag-DNA NCs 的反应时间（120 小时）短得多。与 DNA-Ag NCs 相比，DNA-Cu/Ag NCs 的荧光强度更大（量子产率为 51.2%，而 11.5%）。DNA-Cu/Ag NCs 对单链 DNA 结合蛋白 (SSB) 的检测具有高灵敏度和选择性，线性范围为 1-50 nM，检测限为 0.2 nM，信号与比值为 3。
