【作者】 刘小荣； 邵娜；

【Author】 Xiaorong Liu;Na Shao;College of Chemistry, Beijing Normal University;

【机构】 北京师范大学化学学院；

【摘要】 以DNA为模板合成的Ag NCs具有优良的光学性质,因此受到人们的广泛关注,并已广泛应用于生物识别领域。然而,对于DNA-Ag NCs的发光机理至今仍不是很清楚。我们通过一系列光谱实现证明,DNA-Ag NCs的发光是由于发生了从配体DNA的富电子原子N到Ag NCs金属核的电荷转移。另外,DNA-Ag NCs的光谱呈现不均匀性——发射波长随激发波长变化而变化,我们通过理论公式计算和实验证明,这是因为DNA-Ag NCs中表面等离子体和激子之间发生耦合。我们设计的DNA的链包含两部分,一部分用于诱导Ag NCs的生成,另一部分是能够与溶菌酶特异性结合的核酸适配体,溶菌酶与其适配体结合可以增强Ag NCs的荧光,且(F-F0)/F0与溶菌酶浓度在一定范围内呈线性关系,从而可实现对溶菌酶的检测。该研究对进一步理解DNA-Ag NCs的发光具有重要的意义。更多还原

【Abstract】 DNA-templated silver nanoclusters(DNA-AgNCs) have now been thrust into the limelight, with their superior fluorescence properties and widely biological applications. However, the origin of photoluminescence of DNA-Ag NCs still remains unclear. From UV-visible and fluorescence spectra study, we deem that the luminescence could be attributed to ligand-to-metal charge transfer(LMCT) from electron-rich N atom in DNA to the Ag NCs metal core and subsequent radiative transitions of the complexes. In addition, it was demonstrated that a strong coupling between surface plasmon resonance and fluorescence emission occurred in DNA-Ag NCs, which induce the dependence of emission spectra on excitation wavelength. Moreover, the photoluminescence enhancement,(F-F0)/F0, of the DNA-AgNCs probes we used was sensitive to the variation of lysozyme concentration. This study has significance on understanding the photoluminescence mechanism of DNA-Ag NCs.更多还原