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RUI: Crystallography-Guided Synthesis of DNA-Encapsulated Silver Clusters Chromophores

RUI：晶体学引导合成 DNA 封装的银簇发色团

基本信息

批准号：
2002910
负责人：
Jeffrey Petty
金额：
$ 40万
依托单位：
Furman University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002910&HistoricalAwards=false
关键词：
RUI Crystallography Guided Synthesis DNA

项目摘要

The Macromolecular, Supramolecular, and Nanochemistry Program along with the Chemical Measurement and Imaging Program in the Chemistry Division supports Professor Jeffrey T. Petty at Furman University to control and fine-tune the colors and emissions of nanoscale metal chromophores (color-producing molecules) using DNA strands as scaffolds. This research impacts the burgeoning area of metal-linked DNA constructs that expand the genetic code of DNA for optical sensing and imaging applications. Metals are widely used in society due to their high conductivity, malleability, and reflectivity. As metal particles shrink to nanometer dimensions of 1000 times smaller than the thickness of a human hair, their electrons reorganize and new properties emerge. For example, although bulk silver is highly reflective, clusters of a few-atoms of silver have diverse colors that depend on the cluster size, shape, and charge. Through the combined expertise of Professor Petty at Furman University along with Professors Raquel Lieberman and Robert Dickson at the Georgia Institute of Technology, atomic-resolution structures of nanoscale DNA-silver clusters are measured with X-ray diffraction. The electronic organization of the nanoscale structures are probed over nano- to milli-second time scales with laser-precision. The educational broader impact of the project centers on the mentoring and training of undergraduate students at Furman University, a primarily undergraduate institution, through a comprehensive research experience. Furman undergraduate students spearhead their individual research projects through close collaboration with graduate students and faculty from major research universities such as the Georgia Institute of Technology and the University of Münster.With this support from the Macromolecular, Supramolecular, and Nanochemistry Program and the Chemical Measurement and Imaging Program, Professor Petty’s team at Furman University develops DNA-silver cluster chromophores using a structure-guided approach. Silver clusters with ~10 atoms are stabilized by DNA strands, and the spectra and photophysics of these adducts are encoded via the DNA nucleobases. To date, DNA-silver cluster chromophores have been empirically developed for specific sensing and imaging applications. A recent atomic-level structure of a DNA-silver cluster complex identifies three structural motifs that show how the silvers and DNA are organized. A DNA dimer with two A2C4 strands traps eight silver atoms that are arranged as in the Big Dipper asterism. A subset of five silver atoms mimics the dipper because they have a trapezoid shape. These are separated by metallic bond distances and are likely the chromophoric core of the green-emitting complex. The three other silver atoms resemble the dipper handle because they disperse between pairs of cytosines and join the DNA strands. These three bonding motifs are selectively modified by borrowing tools from chemistry and biochemistry. The modification tools are for chemically modifying nucleobase heteroatoms, enzymatically excising nucleobases, and synthetically linking DNA strands. The electronic environment of the resulting clusters is comprehensively characterized via steady-state, time-resolved, and chirooptical spectroscopies. DNA-cluster conjugates with distinctive spectra are characterized by mass spectrometry to determine the numbers and distributions of silver atoms within the complex. These species are then screened using a wide range of solution conditions to form crystals and analyzed by X-ray diffraction to establish the relationship between the DNA-silver bonding and silver cluster spectra.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

化学系的高分子、超分子和纳米化学项目以及化学测量和成像项目支持弗曼大学的 Jeffrey T. Petty 教授使用 DNA 链作为支架来控制和微调纳米级金属发色团（产生颜色的分子）的颜色和发射。这项研究影响了金属连接 DNA 结构的新兴领域，这些结构扩展了用于光学传感和成像应用的 DNA 遗传密码。金属因其高导电性、延展性和反射性而在社会中得到广泛应用。当金属颗粒缩小到比人类头发丝粗细 1000 倍的纳米尺寸时，它们的电子会重组并出现新的特性。例如，虽然块状银具有高反射性，但银的几个原子簇具有不同的颜色，具体取决于簇的大小、形状和电荷。通过弗曼大学 Petty 教授以及佐治亚理工学院 Raquel Lieberman 和 Robert Dickson 教授的综合专业知识，利用 X 射线衍射测量了纳米级 DNA 银簇的原子分辨率结构。纳米级结构的电子组织可以在纳秒到毫秒的时间尺度上以激光精度进行探测。该项目对教育的更广泛影响集中在通过全面的研究经验对弗曼大学（主要是本科院校）的本科生进行指导和培训。弗曼大学的本科生通过与佐治亚理工学院和明斯特大学等主要研究型大学的研究生和教师密切合作，带头开展个人研究项目。在高分子、超分子和纳米化学项目以及化学测量和成像项目的支持下，弗曼大学佩蒂教授的团队使用结构引导技术开发了 DNA-银簇发色团。方法。具有约 10 个原子的银簇由 DNA 链稳定，这些加合物的光谱和光物理学通过 DNA 核碱基进行编码。迄今为止，DNA-银簇生色团已根据经验开发用于特定的传感和成像应用。最近，DNA-银簇复合物的原子级结构确定了三个结构基序，显示了银和 DNA 的组织方式。具有两条 A2C4 链的 DNA 二聚体捕获了八个银原子，这些原子按照北斗七星的排列方式排列。五个银原子的子集模仿了北斗七星，因为它们具有梯形形状。它们由金属键距分开，很可能是发绿光复合物的发色核心。另外三个银原子类似于北斗柄，因为它们分散在胞嘧啶对之间并连接 DNA 链。通过借用化学和生物化学的工具来选择性地修改这三个键合基序。修饰工具用于化学修饰核碱基杂原子、酶切核碱基以及合成连接 DNA 链。通过稳态、时间分辨和手性光学光谱对所得团簇的电子环境进行了全面表征。通过质谱分析法对具有独特光谱的 DNA 簇缀合物进行表征，以确定复合物中银原子的数量和分布。然后使用各种溶液条件筛选这些物种以形成晶体，并通过 X 射线衍射进行分析，以确定 DNA-银键合和银簇光谱之间的关系。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。