CAREER: A portable nanosensor for ultrasensitive optical detection of airborne agents

可以部署在现实世界中的超灵敏平台可以同时检测数百种分子，这对环境可持续性、法医分析和人类健康至关重要。目前检测这些分子（称为挥发性有机化合物（VOC））的方法在很大程度上受到技术能力，成本和复杂性的限制。利用光来检测和解开VOC信号的复杂性的光学技术是有前途的，但仍在开发中。在这个CAREER项目中开发的平台具有新型纳米材料，可以用光激活，以选择性地捕获和检测空气中的VOC。这种新的检测器对未来的便携式或可穿戴设计具有很高的适应性，并有可能以新的方式加速VOCs的研究。该探测器的研制将为新型传感平台的设计奠定坚实的基础。该项目还将为从小学到研究生院的学生提供巨大的学习机会。主要活动包括开发以社区为重点的互动科学演示，制作K-12教育盒，为高中生开发光学暑期学校，以及创建和传播广泛的可访问虚拟光学资源，包括互动实验室。研究人员的长期愿景涉及将等离子体纳米材料直接转化为复杂基质中的传感应用，例如呼吸，生物流体和现实世界的环境场所。为了实现这一愿景，该CAREER项目旨在开发灵敏、准确的传感器，用于被动检测空气中的挥发性有机化合物（VOC），包括化学战剂、有毒工业化学品、城市野火污染物和呼出气体生物标志物。检测VOC的常用技术，包括质谱法，体积庞大，难以集成到便携式或可穿戴设备中进行连续监测。另一方面，目前检测VOC的便携式设备主要基于电化学检测，其严重缺乏特异性、灵敏度和易用性。多重检测是罕见的，因为需要为每个感兴趣的分子开发特定的系统。为了构建一种适用于实际部署的多路VOC检测的有效便携式设备，将集成两种互补技术：（1）金属有机框架（MOF）的多路复用阵列，用于差异富集目标VOC，嵌入有（2）金属纳米结构，通过表面增强拉曼散射（Sers）现象实现超灵敏的无标记读出。VOC的多路检测将用于通过对实验室中生成的气相样品进行训练来构建高级数据模型。该项目将为开发一种小型化的无源SERS-MOF传感器奠定基础，该传感器可以部署在呼吸传感或环境监测等使用点应用中，以便通过廉价的便携式拉曼光谱仪方便地读取。这种高风险/高回报的方法与便携式设备中常用的监测一组VOC浓度水平的竞争方法有着根本的不同，它将加速在真实的世界环境中对VOC的检测，对人类健康和安全产生巨大影响。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。

Ultrasensitive platforms that can be deployed in real-world situations to detect hundreds of molecules at once are central to environmental sustainability, forensic analysis, and human health. Current approaches to detect such molecules, known as volatile organic compounds (VOCs), are largely limited by technical capabilities, cost, and complexity. Optical techniques that utilize light to detect and untangle the complexity of VOC signals are promising but still under development. The platform developed in this CAREER project features novel nanomaterials that can be activated with light to selectively capture and detect airborne VOCs. This new detector has high adaptability to future portable or wearable designs and has the potential to accelerate the study of VOCs in new ways. The development of the proposed detector will lay a solid foundation for the design of new sensing platforms. This project will also provide tremendous learning opportunities for students from elementary to graduate school. Major activities include the development of community focused interactive scientific demos, production of K-12 educational boxes, development of an optical summer school for high school students, and the creation and dissemination of a wide array of accessible virtual optics resources, including interactive labs. The investigator’s long-term vision involves translating plasmonic nanomaterials to sensing applications directly in complex matrices, such as breath, biofluids, and real-world environmental sites. To realize this vision, this CAREER project seeks to develop sensitive, accurate sensors for passive detection of airborne volatile organic compounds (VOCs), including chemical warfare agents, toxic industrial chemicals, urban wildfire pollutants, and exhaled breath biomarkers. Common techniques to detect VOCs, including mass spectrometry, are bulky and difficult to integrate in portable or wearable devices for continuous monitoring. On the other hand, current portable devices to detect VOCs are largely based on electrochemical detection that greatly lack specificity, sensitivity, and ease. Multiplexed detection is rare, as specific systems need to be developed for each molecule of interest. To build an effective portable device for multiplexed VOC detection suitable for real-world deployment, two complementary technologies will be integrated: (1) a multiplexed array of metal organic frameworks (MOFs) tailored to differentially enrich target VOCs, embedded with (2) metal nanostructures that enable ultrasensitive label-free readout via the surface enhanced Raman scattering (SERS) phenomena. Multiplexed detection of VOCs will be used to build advanced data models by training on gas phase samples generated in the lab. This project will lay the groundwork towards developing a miniaturized passive SERS-MOF sensor that can be deployed in point-of-use applications like breath sensing or environmental monitoring, to be conveniently read out by inexpensive portable Raman spectrometers. This high-risk/high-reward approach is fundamentally different from competing approaches commonly employed in portable devices to monitor the concentration levels of a panel of VOCs and will accelerate their detection in real world settings with great impact on human health and safety.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.