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

该项目将开发高度灵敏的方法，同时检测血液中的许多与疾病相关的分子，称为“生物标记物”。这些生物标记物将通过与发光纳米颗粒结合来检测，这种纳米颗粒被称为量子点(Qds)，充当一个明亮的标签。通过设计容易区分的量子点，研究团队设想了在单个血滴中检测多达45个不同生物标记物的能力。生物标志物的检测将在被称为“光子晶体”(PC)的工程表面上进行，这种表面能够将量子点的亮度放大数千倍，从而允许对量子点进行单独计数。PC还用于将QD光输出引导到特定的方向，测量这些方向以区分每种类型的QD之间的差异。此外，还将开发新的方法，将每个生物标记分子快速转化为PC表面的许多量子点。通过将个人电脑和量子点相结合，传感器可以简单、快速和廉价，使生物标记物测试能够在诊所和医院等场所进行。该团队将开发一个广泛适用的短期课程，名为“你的血液里有什么？”基因组测试与您“将通过Osher终身学习研究所提供。课程内容将根据伍斯基因组生物学研究所提供的面向公众的课程和大型科学博物馆每年举办的“基因组学世界”活动的互动展示进行调整。对复杂介质中的生物分子进行超声敏感、超选择性和高度多元化的检测是疾病诊断、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在走向前所未有的检测极限，但受到复杂程序、热循环和严格的样品制备的阻碍。在光子超材料表面大幅放大半导体量子点收集的光子输出能力方面的最新进展，使具有数字分子精度的分析与小型、低成本仪器兼容。通过应用具有光子晶体荧光放大的量子点标签，可以对目标分子进行数字计数，并通过其外耦合发射模式来区分量子点发射波长，从而执行多路复用。因此，可以实现一步、室温、无酶的microRNA检测方法，其检测下限为全摩尔水平，动态范围为6对数(10)阶，并有可能进一步扩展。在这个项目中，坎宁安和史密斯的实验室将设计和合成新型的QD标签，这些标签结合了工程设计的多光谱亮度、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，调节它们的寿命，并提取它们的发射，以区分多达45个不同的QD标记，用于分子复用。最后，该团队将引入生物分子检测的新范式，其中每个目标分子可以产生多个下游数字分辨率量子点检测事件，以简单快速的方法实现超灵敏的检测极限。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.