Department of Chemistry, The University of Texas at Austin, 105 East 24th Street STOP A5300, Austin, TX 78712 (USA), Fax: (+01) 512-471-0985.
Chemphyschem. 2014 Mar 17;15(4):784-93. doi: 10.1002/cphc.201300767. Epub 2013 Nov 20.
Triplet-state-mediated super-resolution imaging was used to map the positions of fluorescently labeled double-stranded DNA bound to the surface of gold nanorods. In order to isolate individual fluorophores bound to the nanorod surface, imaging conditions were optimized such that the majority of the fluorophores were forced into a triplet dark state, and fluorescence from approximately one molecule at a time was detected. The fluorescence from the emitting single molecule was then fit to a two-dimensional (2D) Gaussian to localize its position relative to the nanorod substrate. The reconstructed super-resolution images showed excellent agreement with the shape and orientation of the nanorods, although, based on correlated atomic force microscopy, they consistently under-estimated nanorod size. The apparent DNA ligand binding on the gold nanorod surface showed significant heterogeneity, with examples of preferential binding to nanorod ends, uniform binding across the nanorod surface, and site-specific binding to a single end of the nanorod. This heterogeneity would be hidden in a typical ensemble or diffraction-limited measurement, highlighting the need for single nanoparticle super-resolution imaging studies.
三重态介导的超分辨率成像技术被用于绘制与金纳米棒表面结合的荧光标记双链 DNA 的位置。为了分离结合在纳米棒表面的单个荧光团，优化了成像条件，使得大多数荧光团被迫进入三重态暗态，并且一次检测大约一个分子的荧光。然后，将发射单分子的荧光拟合到二维（2D）高斯函数，以确定其相对于纳米棒基底的位置。重建的超分辨率图像与纳米棒的形状和取向非常吻合，尽管根据相关原子力显微镜，它们始终低估了纳米棒的尺寸。金纳米棒表面上明显的 DNA 配体结合显示出显著的异质性，例如优先结合到纳米棒的末端、在纳米棒表面均匀结合以及特异性结合到纳米棒的一个末端。这种异质性在典型的集合或衍射限制测量中会被隐藏，这凸显了进行单个纳米粒子超分辨率成像研究的必要性。
