Silver nanocluster emitters in nucleic acid assemblies

加州大学圣巴巴拉分校的Elisabeth Gwinn和Deborah Fygenson获得了大分子、超分子和纳米化学项目的一个奖项，该项目的研究旨在建立对荧光银簇的光谱特性、溶液结构和阵列潜力的理解，这些簇稳定在DNA链和链组装体中。串联HPLC-质谱与在线光学光谱将用于确定这种Ag：DNA的光学性质如何与复合物中所含的银原子和DNA链的数量相关。将开发双链DNA支柱构建体，以将单个银簇保持在限定的几何形状中，并支持纳米级接近的双簇。扩散常数的测量，结合结构建模，将探测是否合并的集群严重破坏设计的组件。单分子显微镜将被用来评估双银集群组件中的支柱为基础的建设和探测是否银集群过渡时刻的偏振签名是由底层的DNA组件。为了表征和使未来开发的定向光学相互作用的这种定向银簇矩，光谱和偏振成像研究将进行银簇阵列上形成的DNA纳米管。微小的发光银团簇被固定在合成DNA链中，开始出现在成像、分子逻辑和选择性传感的创新应用中。由于目前对簇的大小和形状以及它们如何与保持它们稳定的DNA相互作用缺乏了解，进一步的发展受到阻碍。这项工作将建立一个了解银：DNA的颜色和亮度如何取决于银簇的大小和DNA的环境。在DNA构建体上以纳米级接近的方式保持多个簇的策略的发展将使得能够测试簇的取向是否随着时间的推移足够稳定以用于阵列簇的定向相互作用。这样的Ag：DNA构建体可能会通过未来在化学、机械和电子事件中的信号传递、生物分子的新探针以及通过荧光识别太细微而无法用现有显微镜识别的结构扰动来影响技术。高中观众将通过UCSB的科学思想学院，在研究生研究人员开发和教授的迷你课程中接触到这一多学科的工作。本科生参与研究的重点将集中在吸引从加州社区学院转入UCSB的学生。

Elisabeth Gwinn and Deborah Fygenson of the University of California, Santa Barbara are supported by an award from the Macromolecular, Supramolecular and Nanochemistry program for research to build understanding of the spectral properties, solution structures and array potential of fluorescent silver clusters that are stabilized within DNA strands and strand assemblies. Tandem HPLC-mass spectrometry with in-line optical spectroscopy will be used to determine how the optical properties of such Ag:DNAs relate to the number of silver atoms and DNA strands contained in the complexes. Double-stranded DNA strut constructs will be developed to hold individual silver clusters in defined geometries, and to support dual clusters in nanoscale proximity. Measurement of diffusion constants, combined with structural modeling, will probe whether incorporation of the clusters grossly disrupts the designed assemblies. Single molecule microscopy will be used to evaluate polarization signatures of dual silver cluster assemblies held in strut-based constructs and to probe whether silver cluster transition moments are oriented by the underlying DNA assembly. To characterize and enable future exploitation of directional optical interactions of such oriented silver cluster moments, spectral and polarization imaging studies will be carried out on silver cluster arrays formed on DNA nanotubes. Tiny, light-emitting silver clusters that are held within synthetic DNA strands are beginning to emerge in innovative applications for imaging, molecular logic, and selective sensing. Further development is impeded by the current lack of understanding of the cluster sizes and shapes, and of how they interact with the DNA that keeps them stable. This work will build an understanding of how the color and brightness of Ag:DNAs depends on silver cluster sizes and on the DNA surroundings. The development of strategies to hold multiple clusters in nanoscale proximity on DNA constructs will enable tests of whether the orientation of the clusters is stable enough over time to be exploited in directional interactions of arrayed clusters. Such Ag:DNA constructs may impact technology through future use in signaling chemical, mechanical and electronic events; in new probes of biomolecules, and through fluorescence identification of structural perturbations too subtle to identify with existing microscopies. High-school audiences will be exposed to this multi-disciplinary work through UCSB's School for Scientific Thought, in mini-classes developed and taught by graduate student researchers. The emphasis on undergraduate participation in the research will focus on engaging students who transfer to UCSB from California Community Colleges.