Engineering Quantum Dots and Photonic Metamaterials for Ultrasensitive and Multiplexed Digital Resolution Biomolecule Detection

该项目将开发高灵敏度的方法，用于同时检测血液中许多与疾病相关的分子，称为“生物标志物”。这些生物标志物将通过结合到称为量子点（QD）的发光纳米颗粒上来检测，这些纳米颗粒可作为明亮的标签。通过设计易于区分的量子点，研究小组设想能够在单个血滴中检测多达45种不同的生物标志物。生物标志物检测将在被称为“光子晶体”（PC）的工程表面上进行，这些表面能够将QD亮度放大数千倍，从而允许单独计数QD。PC还用于在特定方向上引导QD光输出，所述特定方向被测量以区分每种类型的QD之间的差异。此外，将开发新的方法，可以快速将每个生物标志物分子转化为PC表面上的许多QD。通过结合PC和QD，传感器可以简单，快速，廉价，使生物标志物测试能够在诊所和医院等场所进行。该小组将开发一个广泛接受的短期课程，题为“你的血液中有什么？基因组学测试和你，”将通过Osher终身学习研究所提供。 该课程的各个方面将适用于通过Woese基因组生物学研究所提供的面向公众的项目，以及每年在大型科学博物馆举办的“基因组学世界”活动中的互动展示。对复杂介质中生物分子的超灵敏、超选择性和高度多重检测是疾病诊断、生命科学研究和环境监测的核心组成部分。 新的“数字分辨率”生物分子检测方法正朝着前所未有的检测极限发展，但受到复杂程序、热循环和严格样品制备的阻碍。光子超材料表面基本上放大从半导体量子点收集的光子输出的能力的最新进展使得具有与小型低成本仪器兼容的数字分子精度的测定。应用具有光子晶体荧光放大的QD标签使得可以对目标分子进行数字计数，并通过其外耦合发射模式区分QD发射波长的能力来执行多路复用。因此，可以实现具有阿摩尔水平检测限和6 log（10）数量级动态范围的microRNA的单步、室温、无酶测定，并且具有进一步扩展的潜力。在这个项目中，坎宁安和史密斯实验室将设计和合成新的量子点标签，将工程多光谱亮度，可编码的发射饱和度，和可编码的PC增强因子。量子点将专门与光子超材料表面耦合，以增强它们的激发，调制它们的寿命，并提取它们的发射，以区分多达45个不同的量子点标签，用于分子复用。最后，该团队将介绍一种新的生物分子检测模式，其中每个目标分子都可以产生多个下游数字分辨率QD检测事件，从而通过简单快速的方法实现超灵敏的检测限。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will develop highly sensitive approaches for detecting many disease-related molecules, called “biomarkers,” in blood at the same time. These biomarkers will be detected by binding to light-emitting nanoparticles, called Quantum Dots (QDs), that serve as a bright tag. By designing QDs to be easily distinguished from each other, the research team envisions the capability to detect as many as 45 different biomarkers in a single blood droplet. Biomarker detection will be performed on engineered surfaces called “photonic crystals” (PCs) that are able to amplify the QD brightness by several thousand-fold, allowing QDs to be counted individually. The PCs also serve to direct the QD light output in specific directions that are measured to tell the difference between each type of QD. In addition, new approaches will be developed that can rapidly convert each biomarker molecule into many QDs on the PC surface. By combining PCs and QDs, the sensor can be simple, fast, and inexpensive, enabling biomarker tests to be performed in places like clinics and hospitals. The Team will develop a broadly accessible short course entitled “What’s in Your Blood? Genomics Testing and You,” to be offered through the Osher Lifelong Learning Institute. Aspects of the course will be adapted for public-facing programs offered through the Woese Institute for Genomic Biology and an interactive display at “World of Genomics” events that are offered annually at large science museums.Ultrasensitive, ultraselective, and highly multiplexed detection of biomolecules within complex media is a central component of disease diagnostics, life science research, and environmental monitoring. New “digital resolution” biomolecular detection methods are leading toward unprecedented detection limits, but are hindered by complex procedures, thermal cycling, and stringent sample preparation. Recent advances in the capability for photonic metamaterial surfaces to substantially amplify the collected photon output from semiconductor quantum dots are making assays with digital molecule precision compatible with small, low cost instruments. Applying QD tags with photonic crystal fluorescence amplification makes it possible to digitally count target molecules and to perform multiplexing through the ability to distinguish QD emission wavelengths by their outcoupled emission pattern. As a result, single-step, room temperature, enzyme-free assays for microRNA with attomolar-level detection limits and 6 log(10) orders of dynamic range can be achieved, with the potential to extend even further. In this project, the Cunningham and Smith labs will design and synthesize novel QD tags that incorporate engineered multispectral brightness, encodable emission saturation, and encodable PC enhancement factor. The QDs will specifically couple with photonic metamaterial surfaces to enhance their excitation, to modulate their lifetime, and to extract their emission to differentiate up to 45 distinct QD labels for molecular multiplexing. Finally, the team will introduce a new paradigm for biomolecule detection in which each target molecule can generate multiple downstream digital-resolution QD detection events to achieve ultrasensitive detection limits with simple and rapid methods.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.