The binding reaction of reduced graphene oxide-silver nanocomposites (rGO-AgNCs) with calf thymus single-stranded DNA (ssDNA) was studied by ultraviolet-visible absorption, fluorescence spectroscopy and circular dichroism (CD), using berberine hemisulphate (BR) dye as a fluorescence probe. The absorbance of ssDNA increases, but the fluorescence intensity is quenched with the addition of rGO-AgNCs. The binding of rGO-AgNCs with ssDNA was able to increase the quenching effects of BR and ssDNA, and induce the changes in CD spectra. All of the evidence indicated that there was a relatively strong interaction between ssDNA and rGO-AgNCs. The data obtained from fluorescence experiments revealed that the quenching process of ssDNA caused by rGO-AgNCs is primarily due to complex formation, i.e. static quenching. The increasing trend of the binding equilibrium constant (Ka) with rising temperature indicated that the binding process was an endothermic reaction. The calculated thermodynamic parameters showed that the binding process was thermodynamically spontaneous, and hydrophobic association played predominant roles in the binding of ssDNA to the surface of rGO-AgNCs.

中文翻译：

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单链DNA与还原氧化石墨烯-银纳米复合材料结合的研究。


以小檗碱半硫酸盐（BR）染料为染料，通过紫外-可见吸收、荧光光谱和圆二色性（CD）研究了还原氧化石墨烯-银纳米复合材料（rGO-AgNCs）与小牛胸腺单链DNA（ssDNA）的结合反应。荧光探针。 ssDNA 的吸光度增加，但荧光强度随着 rGO-AgNC 的添加而猝灭。 rGO-AgNCs与ssDNA的结合能够增强BR和ssDNA的猝灭效应，并引起CD光谱的变化。所有证据表明ssDNA和rGO-AgNCs之间存在相对较强的相互作用。荧光实验数据表明，rGO-AgNCs引起的ssDNA猝灭过程主要是由于复合物的形成，即静态猝灭。结合平衡常数（Ka）随着温度的升高呈增加趋势，表明结合过程是吸热反应。计算的热力学参数表明，结合过程是热力学自发的，疏水缔合在ssDNA与rGO-AgNCs表面的结合中起主导作用。