Imec, Kapeldreef 75, Leuven, Belgium.
Anal Chem. 2011 Feb 15;83(4):1307-14. doi: 10.1021/ac102463c. Epub 2011 Jan 24.
We investigated fluorescence quenching and enhancement near gold nanoparticles (GNP) of various sizes using fluorescently labeled hairpin DNA probes of different lengths. A closed hairpin caused intimate contact between the fluorophore and the gold, resulting in an efficient energy transfer (quenching). Upon hybridization with complementary DNA, the DNA probes were stretched yielding a strong increase in fluorescence signal. By carefully quantifying the amount of bound fluorescent probes and the GNP concentrations, we were able to determine the quenching and enhancement efficiencies. We also studied the size and distance dependence theoretically, using both FDTD simulations and the Gersten-Nitzan model and obtained a good agreement between experiments and theory. On the basis of experimental and theoretical studies, we report over 96.8% quenching efficiency for all particle sizes tested and a maximal signal increase of 1.23 after DNA hybridization. The described results also demonstrate the potential of gold nanoparticles for label free DNA sensing.
我们使用不同长度的荧光标记发夹 DNA 探针研究了不同尺寸的金纳米粒子 (GNP) 附近的荧光猝灭和增强。闭合的发夹使荧光团与金紧密接触，导致有效的能量转移（猝灭）。与互补 DNA 杂交后，DNA 探针被拉伸，荧光信号大大增强。通过仔细定量结合的荧光探针和 GNP 浓度，我们能够确定猝灭和增强效率。我们还使用 FDTD 模拟和 Gersten-Nitzan 模型从理论上研究了尺寸和距离的依赖性，并在实验和理论之间获得了很好的一致性。基于实验和理论研究，我们报告了所有测试粒子尺寸的猝灭效率超过 96.8%，并且 DNA 杂交后信号最大增加 1.23。所描述的结果还证明了金纳米粒子在无标记 DNA 传感方面的潜力。
