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，组合文库中的小珠被标记为一系列有机分子，以方便其识别。基因组学项目依靠空间定义的平面阵列来监测数百或数千种不同的寡核苷酸的反应。在宏观世界中，复杂的系统通常通过条形码来简化，条形码是一种极大地简化了数据收集和识别的技术。本提案涉及纳米尺度的金属条形码。它的基础是基于最近发展的化学来生产独立的、圆柱形的胶体金属纳米颗粒（30 - 200纳米宽，0.4 - 4微米长），其中金属成分可以沿着长度交替（例如Pt-Au-Pt-Au-Pt），其中金属段既可以长度调整，也可以选择性地化学功能化。该提案进一步利用了反射率的内在差异的发现，允许单个杆中的金属段通过传统光学显微镜可见。这些创新将条形码（和条形码阅读器）的概念带入了与生物学相关的长度尺度。如果发展得当，这些新材料可能会对生命科学产生巨大影响，包括组合有机合成、基因表达分析、单核苷酸多态性和基因分型检测、高通量筛选、同时（多重）生物测定，甚至流式细胞术等领域：简而言之，在任何需要或需要识别和跟踪大量分子或分子组装的活动中。因此，本提案旨在发展和/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的效用。为此目的，拟议工作的具体研究里程碑包括以下内容：(i)使用最多六种不同的金属制造具有多达十二个可区分片段的金属条形码；（ii）可编程、自动合成纳米条形码的演示；（iii）使高分辨率条码识别（ID）适应窄视场、时变视场和宽视场、静态视场；（四）研制能够同时进行条形码识别和荧光生物测定读数的仪器；(v)展示一种新颖和高度通用的检测机制，该机制允许将许多不同的条形码混合在一起，每种条形码具有不同的化学性质，只有发生化学反应的条形码才能被可视化；（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.