Technische Universität Braunschweig, Physical and Theoretical Chemistry—NanoBioScience, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany.
J Biomed Opt. 2013 Jun;18(6):65001. doi: 10.1117/1.JBO.18.6.065001.
The dynamic concentration range is one of the major limitations of single-molecule fluorescence techniques. We show how bottom-up nanoantennas enhance the fluorescence intensity in a reduced hotspot, ready for biological applications. We use self-assembled DNA origami structures as a breadboard where gold nanoparticle (NP) dimers are positioned with nanometer precision. A maximum of almost 100-fold intensity enhancement is obtained using 100-nm gold NPs within a gap of 23 nm between the particles. The results obtained are in good agreement with numerical simulations. Due to the intensity enhancement introduced by the nanoantenna, we are able to perform single-molecule measurements at concentrations as high as 500 nM, which represents an increment of 2 orders of magnitude compared to conventional measurements. The combination of metallic NPs with DNA origami structures with docking points for biological assays paves the way for the development of bottom-up inexpensive enhancement chambers for single-molecule measurements at high concentrations where processes like DNA sequencing occur.
动态浓度范围是单分子荧光技术的主要限制因素之一。我们展示了自下而上的纳米天线如何在缩小的热点中增强荧光强度，从而为生物应用做好准备。我们使用自组装 DNA 折纸结构作为基板，在纳米精度上定位金纳米粒子 (NP) 二聚体。使用 100nm 金 NP，在粒子之间的间隙为 23nm 时，可获得近 100 倍的强度增强。得到的结果与数值模拟吻合较好。由于纳米天线引入的强度增强，我们能够在高达 500nM 的浓度下进行单分子测量，与传统测量相比，这增加了两个数量级。金属 NP 与具有用于生物分析对接点的 DNA 折纸结构的结合，为开发低成本的自下而上增强室铺平了道路，可用于在发生 DNA 测序等过程的高浓度下进行单分子测量。
