Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India.
Phys Chem Chem Phys. 2014 Aug 28;16(32):17272-83. doi: 10.1039/c4cp02563f. Epub 2014 Jul 14.
This paper describes the intermolecular interactions of gold nanoclusters (Au NCs) with cyanine dyes, namely HITC P, DTTC I, and IR 144. All the cyanine dyes quenched the fluorescence of Au NCs effectively. Steady-state and time-resolved measurements were performed to understand the competition between electron transfer and energy transfer in the Au NCs and cyanine dye system. A significant spectral overlap between the emission spectrum of the Au NCs and the absorption spectrum of cyanine dyes was observed, making both ideal for studying FRET interactions. However, after careful inspection of the steady state spectra and time resolved decays we concluded that photoinduced electron transfer (PET) could be the major pathway to quench the fluorescence intensity of Au NCs. To elucidate the interaction mechanism between Au NCs and cyanine dyes, docking studies were also performed. The docking studies reveal that the quencher molecules, i.e. cyanine dyes, come in close proximity with the 34-cysteine (Cys) in BSA where the Au clusters are located to enable the electron transfer process.
本文描述了金纳米团簇（Au NCs）与花青染料（即 HITC P、DTTC I 和 IR 144）的分子间相互作用。所有花青染料都能有效地猝灭 Au NCs 的荧光。通过稳态和时间分辨测量来理解 Au NCs 和花青染料体系中电子转移和能量转移之间的竞争。Au NCs 的发射光谱与花青染料的吸收光谱之间存在显著的光谱重叠，这使得它们都非常适合研究 FRET 相互作用。然而，在仔细检查稳态光谱和时间分辨衰减后，我们得出结论，光诱导电子转移（PET）可能是猝灭 Au NCs 荧光强度的主要途径。为了阐明 Au NCs 和花青染料之间的相互作用机制，还进行了对接研究。对接研究表明，猝灭剂分子，即花青染料，与 Au 团簇所在的 BSA 中的 34-半胱氨酸（Cys）接近，从而使电子转移过程得以进行。
