SELF BAR-CODED COLLOIDAL METAL NANOPARTICLES

当今生命科学研究的一个共同主线是需要组织和获取复杂分子系统中固有的大量潜在信息。在药物发现中，组合文库中的珠子被标记上一系列有机分子，以便于识别。基因组学项目依靠空间定义的平面阵列来监测成百上千种不同寡核苷酸的反应。在宏观世界中，复杂的系统往往通过条形码得到简化，条形码是一种极大地简化数据收集和识别的技术。该提案涉及纳米级金属条形码。它的基础是最新发展的化学，以生产自由站立的圆柱形胶体金属纳米颗粒(30-200 nm宽，0.4-4微米长)，其中金属成分可以沿长度变化(例如铂-金-铂-金-铂)，其中金属片段可以长度调节和选择性的化学官能化。该提议进一步利用了这一发现，即反射率的内在差异允许用传统的光学显微镜观察单个棒中的金属段。这些创新将条形码(和条形码阅读器)的概念带到了与生物相关的长度秤上。如果开发得当，这些新材料将在生命科学领域产生巨大影响，包括组合有机合成、基因表达分析、单核苷酸多态检测和基因分型、高通量筛选、同步(多路)生物检测，甚至流式细胞术：简而言之，在任何需要或希望识别和跟踪大量分子或分子组合的活动中。因此，本建议旨在发展和/或改进条形码合成、条形码读出、生物测定读出和条形码表面化学，以最大限度地发挥其潜在用途。为此，拟议工作的具体研究里程碑包括：(1)使用最多6种不同的金属制作具有多达12个可区分区段的金属条形码；(2)演示纳米尺度条形码的可编程自动合成；(3)使高分辨率条形码识别适应狭窄、时变和宽静态视野；(4)开发能够同时读出条形码ID和荧光生物测定的仪器；(V)展示一种新颖和高度通用的检测机制，使许多不同的条形码混合在一起，每个条形码具有不同的化学成分，只有那些正在进行化学反应的条形码才能被可视化；和(Vi)在一个条形码上同时定量三种不同的分析物。

A common thread in life science research today is the need to organize and access the vast array of potential information inherent in complex molecular systems. In drug discovery, the beads in combinatorial libraries are tagged with series of organic molecules to facilitate their identification. Genomics projects rely on spatially-defined planar arrays to monitor reactions of hundreds or thousands of different oligonucleotides. In the macroscopic world, complex systems are often simplified by bar coding, a technology that tremendously streamlines data collection and identification. This proposal relates to nanometer-scale metallic bar codes. Its foundation rests on very recently-developed chemistry to produce free-standing, cylindrically-shaped colloidal metal nanoparticles (30 - 200 nm in width, 0.4 - 4 mum length) in which the metal composition can be alternated (e.g. Pt-Au-Pt-Au-Pt) along the length, and in which the metal segments can be both length-tuned and selectively chemically functionalized. The proposal further exploits the finding that intrinsic differences in reflectivity, permit metal segments in individual rods to be visualized by conventional optical microscopy. These innovations have brought the notion of the bar code (and the bar code reader) to biologically-relevant length scales. If properly developed, these novel materials could have an enormous impact in life science, in areas as diverse as combinatorial organic synthesis, analysis of gene expression, detection of single nucleotide polymorphisms and genotyping, high throughput screening, simultaneous (multipexed) bioassays, and even flow cytometry: in short, in any activity in which identifying and tracking a large number of molecules or molecular assemblies is necessary or desirable. Accordingly, this proposal aims to develop and/or improve bar code synthesis, bar code readout, bioassay readout, and bar code surface chemistry, so as to maximize their potential utility. To that end, specific research milestones for the proposed work include the following: (i) fabrication of metallic bar codes with up to twelve distinguishable segments, using up to six different metals; (ii) demonstration of programmable, automated synthesis of nanoscale bar codes; (iii) adaptation of high-resolution bar code identification (ID) to both narrow, time-varying and wide, static fields of view; (iv) development of instrumentation capable of simultaneous bar code ID and fluorescence bioassay readout; (v) demonstration of a novel and highly general detection mechanism that allows in a mixture of many different barcodes, each with different chemistry, only those undergoing a chemical reaction to be visualized; and (vi) simultaneous quantitation of three different analytes on a single bar code.